BD83A24MUF-M (开发中)

Datasheet

4 ch Current Driver Integrated, Built-in MOS for Boost, Boost DC/DC Converter

White LED Driver for Automotive

BD83A24MUF-M

General Description

Key Specifications

This IC is a white LED driver for LCD backlight.

It has MOS for boost and 4 ch current drivers for LED drive,

making it ideal for high brightness LED drive. LED pin

maximum voltage is 50 V, making it suitable for driving

medium LCD panels.

The dimming is controlled by the PWM signal and can be

set up to 20,000: 1@100 Hz. It also supports analog

dimming and can accommodate even higher brightness

ranges by combining with PWM dimming. DC/DC

converters can be controlled for boost applications, and the

input operating voltage range is 4.5 V to 48.0 V.

◼ Input Operating Voltage Range:

◼ Output LED Current Absolute Accuracy:

4.5 V to 48.0 V

±5.0 %@80.1 mA

Ta = -40 °C to +125 °C

200 kHz to 2420 kHz

-40 °C to +125 °C

120 mA/ ch

◼ DC/DC Oscillation Frequency:

◼ Operating Temperature:

◼ LED Maximum Current:

◼ LED Maximum Dimming Ratio:

◼ LED1 to LED4 Pin Maximum Voltage:

20,000: 1@100 Hz

50 V

Package

W (Typ) x D (Typ) x H (Max)

VQFN24FV4040

4.0 mm x 4.0 mm x 1.0 mm

Features

◼ AEC-Q100 Qualified^{(Note 1)}

◼ Functional Safety Supportive Automotive Products

◼ Built-in 4 ch Current Driver for LED Driver

◼ Built-in MOS for Boost

◼ Current Mode Boost DC/DC Converter

◼ Load Switch (M1) Control Pin

◼ DC Dimming Function by Pulse Input

◼ PWM Dimming

Applications

(20,000: 1@100 Hz, 100 Hz to 25 kHz)

◼ Spread Spectrum Function

◼ Automotive CID (Center Information Display) Panel

◼ Navigation

◼ DC/DC Oscillation Frequency External Synchronization

Function

◼ Cluster Panel

◼ HUD (Head Up Display)

◼ LSI Protect Functions (UVLO, OVP, TSD, OCP)

◼ LED Anode/Cathode Short Circuit Protection Function

◼ Other Small and Medium Sized LCD Panel for

Automotive

◼ LED Open/Short Protection Function

(Note 1) Grade 1

Typical Application Circuit

VREG

VCC

CVCC

EN

RCSH

M1

PWM

SYNC

ADIM_P

COMP

RT

LDSW

N.C.

PWM

D2

L1

VOUT

SYNC

D1

COUT

CIN

ADIM_P

SW

ROVP2

ROVP1

EXP-PAD

C^COMPRCOMP

PGND

RRT

PLSET

FAIL

CPLSET

RFAIL

RISET

VREG

VFAIL

ISET

Figure 1. Boost Application Circuit Diagram

〇Product structure : Silicon integrated circuit 〇This product has no designed protection against radioactive rays.

○This product is protected by U.S. Patent No.7,235,954, No.7,541,785 and No.7,944,189.

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Contents

General Description........................................................................................................................................................................1

Features..........................................................................................................................................................................................1

Key Specifications ..........................................................................................................................................................................1

Package..........................................................................................................................................................................................1

Applications ....................................................................................................................................................................................1

Typical Application Circuit ...............................................................................................................................................................1

Contents .........................................................................................................................................................................................2

Pin Configuration ............................................................................................................................................................................3

Pin Descriptions..............................................................................................................................................................................3

Block Diagram ................................................................................................................................................................................5

Description of Blocks ......................................................................................................................................................................6

Absolute Maximum Ratings ..........................................................................................................................................................10

Thermal Resistance......................................................................................................................................................................10

Recommended Operating Conditions...........................................................................................................................................11

Operating Conditions (External Constant Range).........................................................................................................................11

Electrical Characteristics...............................................................................................................................................................12

Typical Performance Curves.........................................................................................................................................................15

Function Descriptions ...................................................................................................................................................................17

PCB Application Circuit Diagram ..................................................................................................................................................28

List of External Components.........................................................................................................................................................29

Selection of Components Externally Connected...........................................................................................................................31

Precautions for PCB Layout..........................................................................................................................................................37

Power Consumption Calculation Example....................................................................................................................................38

Application Circuit Example ..........................................................................................................................................................40

I/O Equivalence Circuit .................................................................................................................................................................41

Operational Notes.........................................................................................................................................................................42

Ordering Information.....................................................................................................................................................................44

Marking Diagram ..........................................................................................................................................................................44

Physical Dimension and Packing Information...............................................................................................................................45

Revision History............................................................................................................................................................................46

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Pin Configuration

(TOP VIEW)

24

23

22

21

20

19

1

2

3

4

5

6

18

17

16

15

14

13

PWM

SYNC

ADIM_P

COMP

RT

LDSW

N.C.

SW

EXP-PAD

PGND

PLSET

FAIL

ISET

7

8

9

10

11

12

Pin Descriptions

Signal Type

Pin No. Pin Name

Function

(Note 1)

PWM dimming signal: The LED current can be controlled according to On Duty of the input

PWM signal.

1

2

PWM

I

External synchronization frequency input / SSCG setting: The internal oscillation

frequency can be externally synchronized by inputting an external clock signal to the SYNC

pin before the Self Diagnosis is completed. When using spread spectrum mode (SSCG),

short the SYNC pin and the REG pin beforehand.

SYNC

I

DC dimming setting: The ISET pin voltage can be changed by On Duty of the pulse signal

input to the ADIM_P pin. When using only PWM dimming, short the ADIM_P pin with the

REG pin.

3

4

ADIM_P

COMP

I

Phase compensating capacitor connection: The reference voltage and LED pin voltage

generated by REF Voltage block are compared and output by Error AMP. Connect a filter for

phase compensation.

A

Resistor connection for oscillation frequency setting: DC/DC oscillation frequency (f_OSC

can be set by connecting a resistor (R_RT) between the RT pin and the GND pin.

)

5

6

RT

A

P

Resistor connection for LED current setting: LED current (I_LED) can be set by connecting

a resistor (R_ISET) between the ISET pin and the GND pin.

ISET

LGND

LED1

LED2

LED3

LED4

Large current ground 1: GND of the current driver (the LED1, LED2, LED3, and LED4

pins).

7

LED cathode connection 1: Open drain output of the current driver ch 1 for LED drive.

Connect to the LED cathode.

8

LED cathode connection 2: Open drain output of the current driver ch 2 for LED drive.

Connect to the LED cathode.

9

LED cathode connection 3: Open drain output of the current driver ch 3 for LED drive.

Connect to the LED cathode.

10

11

LED cathode connection 4: Open drain output of the current driver ch 4 for LED drive.

Connect to the LED cathode.

Overvoltage protection and short circuit protection detection : When OVP pin voltage

rises to 1.21 V or more, the overvoltage protection (OVP) is activated, and DC/DC converters

are switched OFF. If OVP pin voltage is 0.1 V or less for 3.56 ms, Short Circuit Protection

(SCP) is activated, and both DC/DC converter and the current driver are turned OFF.

12

13

OVP

FAIL

A

Error output flag: Outputs the status of protective operation from the FAIL pin. Since this pin

is an open drain output, use a resistor to pull it up to the REG pin, etc.

O

(Note 1) A: Sensitive signal such as detect and reference, I: Input signal from other units, O: Output signal to other units, P: Large current signal susceptible to

impedance, including transient current.

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Pin Descriptions – continued

Signal Type

Pin No. Pin Name

Function

(Note 1)

Switching pulse number setting: Pulse addition function is provided to stabilize DC/DC

converter output voltage even when PWM Duty is low. The number of switching pulses to be

added can be set by the capacitance value connected between the PLSET pin and the GND

pin.

14

PLSET

A

15

16

17

PGND

SW

Large current ground 2: GND of DC/DC converter. Use it for C_OUTground.

P

-

FET drain signal for boost: Switching signal output of DC/DC converter. Connect the SW

pin to the node between the inductor and the rectifier diode.

N.C.

Not connected internally.

Output for driving the load switch gate: The signal output for driving the gate of the load

switch. When the input overcurrent protection is activated, the load switch is turned OFF as

LDSW pin voltage = VCC pin voltage.

18

19

LDSW

CSH

P

A

Input current detection input: The input current is converted to voltage by the input current

detection resistor (R_CSH) connected between the VCC-CSH pin and detected by the CSH pin.

Turns the load switch OFF when the input overcurrent protection is activated.

Power supply voltage input: The input operating voltage range is 4.5 V to 48.0 V, but when

the IC is started, start it with VCC ≥ 5.5 V. The decoupling capacitor (C_VCC) between the VCC

pin and the GND pin should be as close to the IC pin as possible.

20

21

22

VCC

N.C.

REG

P

-

Not connected internally.

Internal reference voltage: Used as the reference voltage for the internal circuit. 5 V is

generated and output by setting the EN pin to High. Connect a capacitance of 2.2 μF for

phase compensation.

A

Small signal ground: Use this for the ground of external components connected to the

REG, RT, COMP, ADIM_P, ISET, PLSET, OVP, and VCC pins.

23

GND

EN

A

Enable input: The EN pin is turned High to activate the internal circuit. The internal circuit

stops and the standby state is set by setting to Low.

24

-

I

EXP-

PAD

-

The EXP-PAD should be connected to the board ground.

(Note 1) A: Sensitive signal such as detect and reference, I: Input signal from other units, O: Output signal to other units, P: Large current signal susceptible to

impedance, including transient current.

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Block Diagram

VCC

CSH

LDSW

EN

LDSW

Driver

VREF

PROTECT

REG

Low side FET /

Pre Driver

PROTECT

Additional

Pulse

PLSET

RT

DC/DC

Control

LOGIC

SW

REG

OSC

SLOPE

+

－

SSCG

PWM

COMP

PGND

CS

AMP

SYNC

COMP

Error

AMP

－

+

LED1

LED2

LED3

LED4

Soft

Start

LDSW

Driver

Minimum

Channel

Selector

PROTECT

UVLO

DC/DC

Control

LOGIC

ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀFAIL

TSD

SCP

OCPH

ISET SCP

FAIL

OCPL

OVP

OPEN Det

SHORT Det

OVP

Current

Driver

Internal

CLK

REF

Voltage

Dimming

Control

PWM

REG

PULSE

-DC

ADIM_P

ISET

CH1 CH2 CH3 CH4

Current Driver

GND

LGND

Figure 2. Internal Block Diagram

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Description of Blocks

Unless otherwise stated, the value in the sentence is the typical value.

1 VREF

Internal reference voltage circuit. By setting the EN pin to High, 5 V is generated and output to the REG pin. REG voltage

is used as the power supply for the internal circuit. Also, this is used to fix each input pin to High voltage outside the IC.

Connect REG capacitance (C_REG= 2.2 μF) to the REG pin for the phase compensation. Note that if C_REGis not connected,

unstable operation such as oscillation will occur.

2 LDSW Driver

Input overcurrent protection circuit. If the voltage between the VCC-CSH pin is 0.1 V or more and continues for 10 μs or

more, the input overcurrent protection is activated, and the load switch (M1) is latched OFF as LDSW pin voltage = VCC

pin voltage. When the input overcurrent protection is detected, the FAIL pin goes Low. A 3 MΩ resistor is connected inside

the IC between the VCC-LDSW pin. Do not connect a resistor between the VCC-LDSW pin because connecting a resistor

between the VCC-LDSW pin outside the IC may prevent the load switch from being turned ON.

When the VCC pin voltage is turned ON setting the EN pin to Low, the voltage between the VCC-LDSW pin may open

momentarily and an inrush current may flow depending on the VCC startup speed and the type of load switch used. Be

sure to check with the actual application.

3 OSC (Oscillator)

Oscillation frequency generator. DC/DC oscillation frequency (f_OSC) can be set by connecting a resistor for oscillation

frequency setting (R_RT) between the RT pin and ground. In addition, DC/DC oscillation frequency can be externally

synchronized by inputting the external synchronization frequency (f_SYNC) to the SYNC pin.

4 SSCG (Spread Spectrum Clock Generator)

Spread spectrum circuit. The spread spectrum function (SSCG) is activated by shorting the SYNC pin and the REG pin.

Noise peaks can be reduced by periodically changing the oscillation frequency by SSCG. The fluctuation range of the

frequency due to SSCG is from 100 % to 92 % of the set oscillation frequency. The oscillation frequency fluctuation period

is 2.3 kHz.

5 SLOPE

This circuit generates a saw wave that serves as the source of the switching pulse of DC/DC converter. SLOPE output

signal and COMP pin voltage are compared, and a switching pulse is generated.

6 Minimum Channel Selector

Selector circuit for detecting LED pin voltages. Selects the lowest pin voltage among LED1 to LED4 pin voltages and inputs

it in Error AMP.

7 Error AMP (Error Amplifier)

This is an error amplifier that takes LED control voltage and the smallest value of the LED1 to LED4 pin voltages as input.

Phase compensation can be set by connecting a resistor and a capacitor to the COMP pin.

8 Soft Start

Soft start circuit for DC/DC converters. This function is used to suppress a steep increase in the inductor current at startup

and an overshoot in the output voltage. Controls the change in switching Duty by limiting the rising edge of the output of

Error AMP (COMP pin voltage) with the soft start function.

9 PWM COMP (PWM Comparator)

This comparator compares COMP pin voltage, which is the output of Error AMP, with SLOPE output signal. Controls the

Duty of the switching pulse of DC/DC converter.

10 Additional Pulse

This circuit adds switching pulses of DC/DC converter. With the pulse addition function, the LED current can be supplied

stably even when the PWM dimming ratio decreases.

11 DC/DC Control LOGIC

This circuit generates the logic of the built-in Low side FET for boost output from the SW pin.

12 Low side FET / Pre Driver

Built-in Low side FET for boost output from the SW pin and its driving circuit.

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Description of Blocks - continued

13 Internal CLK

This circuit generates the internal reference clock. It is a clock of 2.3 MHz and used as a counter.

14 Dimming Control

This circuit controls the dimming rate during PWM dimming.

15 Current Driver / ISET

Current driver circuit for lighting LED. LED current can be set by connecting a resistor to the ISET pin.

In addition, the LED current can be set by the On Duty input signal of the ADIM_P pin.

16 PULSE-DC

This block smoothes the pulse input to the ADIM_P pin and outputs the DC voltage to the ISET block.

The DC voltage level can be set by the On Duty input signal of the ADIM_P pin.

17 PROTECT

Outputs the status of protective operation from the FAIL pin. Since this pin is an open drain output, connect it to the REG

pin with a resistor. If the status of protective operation is not monitored, turn the FAIL pin to OPEN or connect to the GND

pin.

17.1 UVLO (Under Voltage Lock Out)

Under Voltage Lock Out. When VCC pin voltage is 4.10 V or less or REG pin voltage is 3.95 V or less, Under

Voltage Lockout (UVLO) is activated, and the load switch (M1), DC/DC switching, and current driver turn OFF.

When VCC pin voltage is 4.25 V or more and REG pin voltage is 4.10 V or more, UVLO is released and the IC

restarts from Self Diagnosis. When UVLO is detected, output of the FAIL pin does not change. When the FAIL pin

is pulled up to the REG pin, FAIL pin voltage will also drop as REG pin voltage is decreased.

17.2 TSDLED (Thermal Shutdown for Current Driver)

This is a temperature protection circuit that monitors the vicinity of the current driver on the chip. Prevents chip

temperature from rising due to output current fault. When the chip temperature rises to 175 °C or more, the

temperature protection circuit (TSDLED) is activated, the load switch (M1), DC/DC switching, and current driver

are turned OFF. When TSDLED is detected, the FAIL pin goes Low. When the chip temperature falls 150 °C or

less, TSDLED is released, the IC restarts from Self Diagnosis.

17.3 TSDREG (Thermal Shutdown for REG)

This is a temperature protection circuit that monitors the vicinity of the REG pin on the chip. Prevents chip

temperature from rising due to the REG pin failure. When the chip temperature rises to 175 °C or more, the

temperature protection circuit (TSDREG) is activated, and REG pin voltage, load switch (M1), DC/DC switching,

and current driver turn OFF. When TSDREG is detected, the FAIL pin goes Low. When the chip temperature falls

150 °C or less, TSDREG is released and the IC restarts from Self Diagnosis.

17.4 OCPL (Over Current Protection for Low side)

When the current flowing through Low side FET (the SW pin) becomes 3.6 A or more, the overcurrent protection

(OCPL) is activated and only DC/DC switching is stopped. If the current is less than 3.6 A, the overcurrent

protection is released, and switching is resumed. When OCPL is detected, output of the FAIL pin does not change.

17.5 OVP (Over Voltage Protection)

Output overvoltage protection circuit. When OVP pin voltage (resistor division of DC/DC converter output voltage)

becomes to 1.21 V or more, the overvoltage protection circuit (OVP) activates and only DC/DC switching is

stopped. When OVP pin voltage falls 1.16 V or less, OVP is released. When OVP is detected, output of the FAIL

pin goes Low.

17.6 OPEN Det (LED Open Detection)

LED open protection circuit. When any of LED1 to LED4 pin voltages is 0.3 V or less and OVP pin voltage is 1.21

V or more, LED open protection (OPEN Det) is activated, and the current driver is latched OFF only for the LED

row that is open. OPEN Det is released when V_EN= Low or UVLO is detected. When OPEN Det is detected, the

FAIL pin goes Low.

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17 PROTECT – continued

17.7 SHORT Det (LED Short Detection)

LED short protection circuit. When LED pin voltage is 5 V or more for 3.56 ms (counter), LED short protection

(SHORT Det) is activated, and the current driver is latched OFF only for the corresponding LED row. However,

the counter is reset when LED pin voltage does not satisfy the detection condition prior to SHORT Det being

activated. SHORT Det is released when V_EN= Low or UVLO is detected. Since the 3.56 ms counter is counted up

only when PWM = High, the time until SHORT Det is detected varies depending on PWM Duty. When SHORT

Det is detected, the FAIL pin goes Low. SHORT Det can be detected when the PWM pulse width is 20 μs (Min) or

more.

17.8 SCP (Short Circuit Protection)

Short Circuit Protection circuit. If any of the LED1 to LED4 pin voltages are 0.3 V or less or OVP pin voltage is 0.1

V or less for 3.56 ms (counter), the Short Circuit Protection (SCP) is activated, and the load switch (M1), DC/DC

switching, and current driver turn OFF. However, the counter is reset when each pin voltage does not satisfy the

condition prior to SCP being activated. The SCP is released when V_EN= Low or UVLO is detected. When SCP is

detected, the FAIL pin goes Low.

17.9 OCPH (Over Current Protection for High side) / LDSW Driver

Input overcurrent protection circuit. If a condition in which the voltage between the VCC-CSH pin is 0.1 V or more

continues for 10 μs or more, the input overcurrent protection (OCPH) is activated. It becomes LDSW pin voltage

= VCC pin voltage and the load switch (M1), DC/DC switching, and current driver turn OFF. The OCPH is released

when V_EN= Low or UVLO is detected. When OCPH is detected, the FAIL pin goes Low.

17.10 ISET Pin Fault (ISET-GND Short Protection)

ISET pin fault protection circuit. When the resistance value connected to the ISET pin falls 3.5 kΩ or less (when

ADIM_P pin voltage = REG pin voltage), ISET pin fault protection is activated, and the load switch (M1), DC/DC

switching, and current driver are turned OFF. If the resistance value connected to the ISET pin is more than 3.5

kΩ (when ADIM_P pin voltage = REG pin voltage), ISET pin fault protection is released, and the load switch,

DC/DC switching, and current driver are turned ON. When ISET pin fault is detected, the FAIL pin goes Low.

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Description of Blocks – continued

Detect Conditions and Operation at Detection of Each Protection Function (All values in the table are Typ values)

Operation at Detection

Detect Condition

Protection Function

(Block Name)

No.

1

Load

DC/DC

Current

Driver

FAIL

[Detect]

[Release]

Switch Switching

Under Voltage

Lockout

VCC ≤ 4.10 V

or

VCC ≥ 4.25 V

and

High

(Note 4)

OFF

(UVLO)

V_REG≤ 3.95 V

V_REG≥ 4.10 V

Thermal Shutdown

LED

2

3

Tj ≥ 175 °C

Tj ≤ 150 °C

OFF

Low

(TSDLED)

Thermal Shutdown

REG

OFF

ON

(TSDREG)

Overcurrent

Protection

(OCPL)

High

(Note 4)

4

5

I_SW≥ 3.6 A

I_SW< 3.6 A

ON

OFF

Overvoltage

Protection

(OVP)

V_OVP≥ 1.21 V

V_OVP≤ 1.16 V

ON

Low

Only

LED Open

Protection

(OPEN Det)

V_LEDn^{(Note 1)}≤ 0.3 V

and

V_EN= Low^{(Note 5)}

or

detection Latch

6

7

ON

LED pin

is OFF

Only

Low

V_OVP≥ 1.21 V

Detects UVLO

LED Short

Protection

Detects

V_EN= Low^{(Note 5)}

or

detection Latch

V_LEDn^{(Note 1)}≥ 5.0 V

for 3.56 ms or more^{(Note 2)}

LED pin

is OFF

Low

(SHORT Det)

Detects UVLO

Detects

V_LEDn^{(Note 1)}≤ 0.3 V

or

Short Circuit

Protection

(SCP)^{(Note 3)}

V_EN= Low^{(Note 5)}

or

Latch

Low

8

9

OFF

V_OVP≤ 0.1 V

Detects UVLO

for 3.56 ms or more

Detects

Input

V_EN= Low^{(Note 5)}

or

Overcurrent

Protection

(OCPH)^{(Note 3)}

ISET-GND

voltage between the

VCC-CSH pin ≥ 0.1 V

for 10 μs or more

Latch

Low

OFF

Detects UVLO

ISET resistor ≤ 3.5 kΩ

ISET resistor > 3.5 kΩ

10 Short Protection

(ISET Pin Fault)

Low

(when V_{ADIM_P}= V_REG

)

(when V_{ADIM_P}= V_REG)

(Note 1) LEDn indicates one of the LED1 to LED4 pins.

(Note 2) LED pin voltage of at least 1 channel shall be less than V_LEDCTL(MIN)x 1.2. When LED pin voltages of all channels are 2.4 V or more, the LED short protection

does not operate. Since the 3.56 ms counter is counted up only when PWM = High, the time until SHORT Det is detected varies depending on PWM Duty.

(Note 3) When Short Circuit Protection (SCP) and Input Overcurrent Protection (OCPH) are detected at the same time, the operation of Input Overcurrent Protection

takes precedence.

(Note 4) When pulled up to any voltage, it becomes High output.

(Note 5) The Low width of EN need 10 µs or more.

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Absolute Maximum Ratings (Ta = 25 °C)

Parameter

Symbol

Rating

Unit

V

VCC, LDSW, CSH, SW Pin Voltage

VCC, V_LDSW, V_CSH, V_SW

VCC-V_LDSW, VCC-V_CSH

V_LED1, V_LED2, V_LED3, V_LED4,V_OVP

V_RT, V_COMP, V_ISET, V_PLSET

-0.3 to +50.0

-0.3 to +7.0

-0.3 to +50.0

-0.3 to V_REG

-0.3 to +7.0

-55 to +150

150

Voltage Between VCC-LDSW, VCC-CSH Pin

V

LED1, LED2, LED3, LED4, OVP Pin Voltage

RT, COMP, ISET, PLSET, Pin Voltage

V

EN, REG, SYNC, PWM, ADIM_P, FAIL Pin Voltage V_EN, V_REG, V_SYNC, V_PWM, V_{ADIM_P}, V_FAIL

V

Storage Temperature Range

Tstg

°C

Maximum Junction Temperature

Tjmax

°C

Caution 1: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit

between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is

operated over the absolute maximum ratings.

Caution 2: Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in deterioration of the

properties of the chip. In case of exceeding this absolute maximum rating, design a PCB with thermal resistance taken into consideration by increasing

board size and copper area so as not to exceed the maximum junction temperature rating.

Thermal Resistance^{(Note 1)}

Thermal Resistance (Typ)

Parameter

Symbol

Unit

1s^{(Note 3)}

2s2p^{(Note 4)}

VQFN24FV4040

Junction to Ambient

Junction to Top Characterization Parameter^{(Note 2)}

θ_JA

112.2

26.0

33.8

12.0

°C/W

Ψ_JT

(Note 1) Based on JESD51-2A (Still-Air). The BD83A24MUF-M chip is used.

(Note 2) The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside

surface of the component package.

(Note 3) Using a PCB board based on JESD51-3.

(Note 4) Using a PCB board based on JESD51-5, 7.

Layer Number of

Measurement Board

Material

FR-4

Board Size

Single

114.3 mm x 76.2 mm x 1.57 mmt

Top

Copper Pattern

Thickness

70 μm

Footprints and Traces

Layer Number of

Measurement Board

Thermal Via^{(Note 5)}

Material

FR-4

Board Size

114.3 mm x 76.2 mm x 1.6 mmt

2 Internal Layers

Pitch

Diameter

4 Layers

1.20 mm

Φ0.30 mm

Top

Copper Pattern

Bottom

Thickness

70 μm

Copper Pattern

Thickness

Copper Pattern

Thickness

70 μm

Footprints and Traces

74.2 mm x 74.2 mm

35 μm

74.2 mm x 74.2 mm

(Note 5) This thermal via connect with the copper pattern of layers 1,2, and 4. The placement and dimensions obey a land pattern.

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BD83A24MUF-M

Recommended Operating Conditions

Operating Range

Max

Parameter

Symbol

Unit

Min

4.5

Power Supply Voltage^{(Note 1)}

VCC

f_OSC

48.0

V

DC/DC Oscillation Frequency Range

(SSCG = OFF)

200

2420

kHz

PWM Frequency Range^{(Note 2)}

f_PWM

0.1

40

18

25.0

400

100

kHz

%

ADIM_P Pin Input Frequency Range^{(Note 3)}

ADIM_P Pin Input On Duty Range^{(Note 3)}

f_{ADIM_P}

D_{ADIM_P}

Higher of

Lower of

External Synchronized Frequency Range^{(Note 4)}

f_SYNC

kHz

200 or f_OSCx 0.9

700 or f_OSCx 1.1

External Synchronized Pulse Duty Range^{(Note 5)}

LED Current Setting Range^{(Note 6)}

Operating Temperature

D_SYNC

I_LED

40

20

60

%

mA

°C

120

Topr

-40

+125

(Note 1) When IC is started, the voltage must be UVLO release voltage or more. Therefore, consider the power supply drop caused by the parasitic resistor

and start the IC at VCC ≥ 5.5 V.

VCC(Min) = 4.5 V is the minimum value of VCC that can operate the IC alone. The minimum value of power supply voltage that can be set depends on

the connected LED load and external components.

(Note 2) Generally, flickering of LEDs is easier to see when the dimming frequency is set lower than 100 Hz. Set after confirming with the actual device evaluation.

(Note 3) If you input a frequency outside the operating range to the ADIM_P pin, the LED flicker will be more visible. Set after confirming with the actual device

evaluation.

(Note 4) When the external synchronization function is not used, connect the SYNC pin to V_REG(SSCG = ON) or GND (SSCG = OFF).

(Note 5) When using the external synchronization function, switching from the external synchronization state to the internal oscillation frequency is not possible

during stable operation.

(Note 6) The amount of current per channel that can be set by the resistor (R_ISET) connected to the ISET pin ( D_{ADIM_P}= 100 % ). Set the LED current so that the

maximum junction temperature (Tjmax) is not exceeded.

Operating Conditions (External Constant Range)

Operating Range

Parameter

Symbol

Unit

Min

1.0^{(Note 7)}

11.0

Typ

Max

4.7

53.0

45.0

10

REG Capacitance

C_REG

R_ISET

R_RT

2.2

μF

kΩ

nF

μF

Resistor for LED Current Setting

Resistor for Oscillation Frequency Setting

PLSET Capacitance

-

3.8

C_PLSET

C_VCC

-

Input Capacitance 1

1^{(Note 7)}

10^{(Note 7)}

20^{(Note 7)}

-

(Note 8)

Input Capacitance 2

C_INVCC

-

Output Capacitance

C_OUT

100

(Note 7) Set the capacitance so that it does not fall below the minimum value in consideration of temperature characteristics, DC bias characteristics, etc.

(Note 8) C_INVCCmeans the total capacitance of C_INand C_VCC

.

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BD83A24MUF-M

Electrical Characteristics

(Unless otherwise specified, VCC = 12 V, Ta = -40 °C to +125 °C)

Standard Value

Unit

mA

Conditions

Parameter

Symbol

Min

Typ

Max

10

V_EN= 5 V, V_SYNC= 0 V,

V_PWM= 0 V, C_IN= 10 μF,

RT = OPEN, ISET = OPEN,

Circuit Current

I_CC

-

V_{ADIM_P}= V_REG

,

Resistor between

V_LEDn-GND = 10 kΩ

Standby Current

[VREF]

I_ST

-

0

10

μA

V

V_EN= Low

REG Output Voltage

[DC/DC Converter]

SW Pin ON Resistor

V_REG

4.7

5.0

5.3

I_REG= -5 mA, C_REG= 2.2 μF

R_{ON_SW}

V_LEDCTL

-

0.2

0.4

Ω

V

I_SW= 50 mA

R_ISET= 15.1 kΩ,

V_{ADIM_P}= V_REG

R_ISET= 15.1 kΩ,

V_COMP= 1.0 V,

V_LED= 1.5 V,

LED Control Voltage

0.67

0.77

0.87

COMP Sink Current

I_COMPSINK

150

220

290

μA

V_{ADIM_P}= V_REG

R_ISET= 15.1 kΩ,

V_COMP= 1.0 V,

V_LED= 0 V,

COMP Source Current

I_COMPSOURCE

-290

-220

-150

V_{ADIM_P}= V_REG

Oscillation Frequency 1

Max Duty 1

f_OSC1

D_{UTY_MAX1}

f_OSC2

270

95

300

-

330

-

kHz

%

R_RT= 33.3 kΩ

R_RT= 3.8 kΩ

V_PLSET= 0 V

Oscillation Frequency 2

PLSET Charge Current

PLSET Set Voltage

1980

35

2200

50

2420

65

kHz

μA

V

I_PLSET

V_PLSET

0.4

0.5

0.6

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BD83A24MUF-M

Electrical Characteristics – continued

(Unless otherwise specified, VCC = 12 V, Ta = -40 °C to +125 °C)

Standard Value

Parameter

[Current Driver]

Symbol

Unit

Conditions

Min

Typ

Max

R_ISET= 15.1 kΩ,

mA

%

LED Current Absolute Variation

I_LEDn

76.1

0

80.1

84.1

V_{ADIM_P}= V_REG

R_ISET= 15.1 kΩ,

V_{ADIM_P}= V_REG

LED Current Relative Variation

(Note 1)

I_LEDREL

R_ISETLIM

t_PWMMIN

-

3.5

-

5

-

ISET-GND Short Protection

Resistor

-

kΩ

μs

V_{ADIM_P}= V_REG

PWM Dimming Minimum Pulse

Width

f_PWM= 100 Hz to 25 kHz,

I_LED= 80.1 mA

0.5

-

PWM Dimming Frequency

PWM Low Section Detect Time

[Logic Input (EN)]

f_PWM

0.1

-

25.0

35.6

kHz

ms

t_PWML

21.4

28.5

Input High Voltage

V_INH1

V_INL1

R_IN1

2.1

-

V

Input Low Voltage

0.5

150

Input Resistor

50

100

kΩ

V_EN= 5 V

[Logic Input (PWM, SYNC, ADIM_P)]

Input High Voltage

Input Low Voltage

Input Resistor

V_INH2

2.1

-

V

V_INL2

R_IN2

0.5

150

50

100

kΩ

V_PWM= V_SYNC= V_{ADIM_P}= 5 V

(Note 1) I_LEDREL= (I_LEDn(MAX)– I_LEDn(MIN)) / I_LEDn(AVE)x 100

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BD83A24MUF-M

Electrical Characteristics – continued

(Unless otherwise specified, VCC = 12 V, Ta = -40 °C to +125 °C)

Standard Value

Parameter

[PROTECT]

Symbol

Unit

Conditions

Min

Typ

Max

VCCUVLO Detect Voltage

VCCUVLO Release Voltage

REGUVLO Detect Voltage

REGUVLO Release Voltage

OVP Detect Voltage

V_UVLOVCC1

V_UVLOVCC2

V_UVLOREG1

V_UVLOREG2

V_OVPDET

3.90

4.05

3.75

3.90

1.173

4.10

4.25

3.95

4.10

1.210

4.30

4.45

4.15

4.30

1.247

V

VCC = Sweep down

VCC = Sweep up

V_REG= Sweep down

V_REG= Sweep up

V_OVP= Sweep up

OVP Detect Voltage

Hysteresis Width

V_OVPHYS

-

50

-

mV

V_OVP= Sweep down

Input OCP Detect Voltage

V_OCPH

V_LDSW

I_CSH

80

4.4

100

5.4

120

6.4

mV

V

VCC-V_CSH= Sweep up

V_CSH= VCC

VCC-V_LDSW

LDSW Operation Voltage

at Input OCP Release

CSH Pin Input Current

V_CSH= 12 V

-0.8

3.14

0.0

+0.8

4.06

μA

A

OCPL Detect Current

I_OCPL

3.60

V_LED= Sweep down

V_OVP≥ V_OVPDET

LED Open Protection Detect Voltage

V_OPEN

0.25

0.30

0.35

V

LED Anode SCP Detect Voltage

LED Cathode SCP Detect Voltage

V_SCP1

V_SCP2

t_SCP1

t_SCP2

V_SHORT

t_INICK

0.05

0.25

0.10

0.30

0.15

0.35

V

V_OVP= Sweep down

V_LED= Sweep down

LED Anode SCP Detect

Delay Time

2.67

3.56

4.45

ms

LED Cathode SCP Detect

Delay Time

LED Short Protection Detect Voltage

Initial Check Time

4.7

5.34

-

5.0

7.12

1.0

5.3

8.90

2.0

V

V_LED= Sweep up

ms

kΩ

FAIL Pin ON Resistor

R_FAIL

I_FAIL= 1 mA

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BD83A24MUF-M

Typical Performance Curves

(Reference data, unless otherwise specified VCC = 12 V)

10

8

5.3

5.2

5.1

5.0

4.9

4.8

4.7

6

4

2

0

4

15

26

37

48

-40 -20

0

20 40 60 80 100 120

Temperture : Ta [°C]

Power Supply Voltage : VCC [V]

Figure 3. Circuit Current vs Power Supply Voltage

Figure 4. REG Output Voltage vs Temperature

330

320

310

300

290

280

270

2420

2376

2332

2288

2244

2200

2156

2112

2068

2024

1980

-40 -20

0

20 40 60 80 100 120

-40 -20

0

20 40 60 80 100 120

Temperature : Ta [°C]

Figure 5. Oscillation Frequency 1 vs Temperature

(R_RT= 33.3 kΩ)

Figure 6. Oscillation Frequency 2 vs Temperature

(R_RT= 3.8 kΩ)

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BD83A24MUF-M

Typical Performance Curves – continued

(Reference data)

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

84

83

82

81

80

79

78

77

76

0.0

20 30 40 50 60 70 80 90 100 110 120

-40 -20

0

20 40 60 80 100 120

Temperture : Ta [°C]

LED Current : I_LED[mA]

Figure 7. LED Control Voltage vs LED Current

Figure 8. LED Current vs Temperature

100

90

80

70

60

50

100

90

80

70

60

50

8

10

12

14

16

8

10

12

14

16

Power Supply Voltage : VCC [V]

Figure 9. Efficiency 1 vs Power Supply Voltage

(R_RT= 33.3 kΩ, R_ISET= 15.1 kΩ,

Figure 10. Efficiency 2 vs Power Supply Voltage

(R_RT= 3.8 kΩ, R_ISET= 15.1 kΩ,

Number of LED Series = 10, Number of LED Parallels = 4)

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BD83A24MUF-M

Function Descriptions

Unless otherwise stated, the value in the sentence is the Typ value.

1 Current Driver

This model has a built-in 4 ch current driver. The LED current setting range per channel is 20 mA to 120 mA, and the LED

current can be adjusted by the resistance value between the ISET pin and GND.

1.1 How to Set LED Current

1.4 PWM Low Section Detect Function

1.2 When Using Analog PWM Dimming (ADIM_P)

1.3 When Using PWM Dimming

1.5 LED Pin Handling of Unused Channels

1.6 When Setting the LED Current Above 120 mA

1.1 How to Set LED Current

The LED current I_LEDcan be calculated using the following equation.

푉

푅

¹⁰× ꢂꢃ⁶

[mA]

ꢀ푆ꢁ푇

퐼_퐿퐸퐷

=

×

Resistance Value Setting Example (V_{ADIM_P}= V_REG

)

9

ꢀ푆ꢁ푇

ISET Resistor [kΩ]

LED Current [mA]

퐼_퐿퐸퐷: Output current per channel (LED current)

(Recommended operating condition:

20 mA to 120 mA)

53.0

30.0

15.1

11.0

22.8

40.3

80.1

110

ꢄ_ꢅꢆ퐸ꢇ: ISET pin voltage 1.089 V

(When ADIM_P pin voltage V_{ADIM_P}= V_REG

ꢈ_ꢅꢆ퐸ꢇ: Resistor for LED current setting

(Recommended operating condition:

11 kΩ to 53 kΩ)

)

When R_ISET≤ 3.5 kΩ, ISET pin short protection detect is

activated, and output of the LED current is stopped.

120

110

100

90

80

70

60

50

40

30

20

11

17

23

29

35

41

47

53

R_ISET[kΩ]

Figure 11. I_LEDvs R_ISET(V_{ADIM_P}= V_REG

)

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BD83A24MUF-M

1 Current Driver – continued

1.2 When Using Analog PWM Dimming (ADIM_P)

ISET pin voltage can be adjusted according to the input Duty to the ADIM_P pin. The LED current I_LEDcan be calculated

from the following equation as described above.

퐼_퐿퐸퐷: Output current per channel (LED current)

(Recommended operating condition:

20 mA to 120 mA)

푉

푅

¹⁰× ꢂꢃ⁶

[mA]

ꢀ푆ꢁ푇

퐼_퐿퐸퐷

=

×

9

ꢀ푆ꢁ푇

ꢄ

_ꢅꢆ퐸ꢇ: ISET pin voltage 1.089 V

However, V_ISETcan be adjusted according to ADIM_P

pin input On Duty D_{ADIM_P}as follows:

ꢈ_ꢅꢆ퐸ꢇ: Resistor for LED current setting

(Recommended operating condition:

11 kΩ to 53 kΩ)

ꢊ_{퐴퐷ꢅ푀_푃}: ADIM_P pin input On Duty

(Recommended operating condition:

18 % to 100 %)

ꢄ

= ꢂ.ꢃ8ꢉ [V]

ꢅꢆ퐸ꢇ

(90 % ≤ D_{ADIM_P}≤ 100 %)

ꢄ

= ꢂ.ꢃ8ꢉ × ¹⁰× ꢊ_{퐴퐷ꢅ푀_푃}[V]

ꢅꢆ퐸ꢇ

(18 % < D_{ADIM_P}< 90 %)

9

Note : Note that the LED current set by R_ISETand the ADIM_P pin cannot be set below 10 mA.

100

90

80

70

60

50

40

30

20

10

0

18

28

39

49

59

69

80

90

100

D_{ADIM_P}[%]

Figure 12. I_LEDvs D_{ADIM_P}(R_ISET= 15.1 kΩ)

1.3 When Using PWM Dimming

The LED current can be controlled according to On Duty of the PWM signal input to the PWM pin. However, in the region

where the ON time of the LED current is less than 0.5 μs or the OFF time is less than 0.5 μs, the pulse time is shorter than

PWM dimming minimum pulse width, so it cannot be used regularly. It is okay to use this region transiently, so it is also

possible to set PWM Duty = 0 % and 100 %.

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BD83A24MUF-M

1 Current Driver – continued

1.4 PWM Low Section Detect Function

Counting starts when PWM = High is switched to Low in the V_EN= High state. When PWM Low section reaches 28.5 ms,

the operation is regarded as OFF state. After that, when PWM input is turned High, switching operation (pre-boost) is

restarted.

1.5 LED Pin Handling of Unused Channels

VOUT

This model has four built-in constant current circuits.

The current can be supplied to the LED by setting the

PWM pin to High, and the LED current can be set by

inserting a resistor between the ISET pin and GND. The

LED current that can be supplied per row is 20 mA to

120 mA.

Pull down the LED pin of the unused channel to GND

with 10 kΩ.

10 kΩ

LED4

LED3

LED2

LED1

Figure 13. When Setting LED4 Unused

1.6 When Setting the LED Current Above 120 mA

The LED1 to LED4 pins can be used in bundles.

For example, as shown in the figure on the right, if

LED1, LED2, LED3, and LED4 are shorted, 4 times the

current set by the ISET pin can be passed.

VOUT

When using only 2 channels in a bundle, mount the

pulled-down resistor for each LED pin for unused

channels (2 channels).

When connected to multiple LED pins with a resistor,

the voltage value may be out of the set range and may

not be recognized as an unused channel. In this case,

the unintentional protection function may be activated,

so perform the LED pin handling correctly.

LED4

LED3

LED2

LED1

Figure 14. Application Example When LED Pins Are Shorted

VOUT

10 kΩ

LED4

10 kΩ

LED3

LED2

LED1

LED3

LED2

LED1

Figure 15. Correct LED Pin Handling When Multiple

Channels Are Unused

Figure 16. Wrong LED Pin Handling When Multiple

Channels Are Unused

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BD83A24MUF-M

Function Descriptions – continued

Unless otherwise stated, the value in the sentence is the Typ value.

2 DC/DC Converter

Detects the lowest voltage among LED1 to LED4 pin voltages (LED cathode voltages) in Minimum Channel Selector block

and inputs it to Error AMP. The reference voltage of Error AMP is generated in REF Voltage block based on R_ISETresistance

value, which becomes LED pin control voltage. The output of Error AMP is compared with the output of SLOPE block by

PWM COMP block, and a switching signal is output to the SW pin through DC/DC Control LOGIC.

2.1 LED Control Voltage V_LEDCTL

2.5 DC/DC Oscillation Frequency f_OSC

2.6 Pulse Addition Function

2.7 External Synchronization / Spread Spectrum

Function (SSCG)

2.2 VCC Input Voltage and Number of LED Series

2.3 LED Variation and Series Number

2.4 Overvoltage Protection Function OVP

2.8 LSDET Function

2.1 LED Control Voltage V_LEDCTL

DC/DC converter operates so that the lowest voltage among LED1 to LED4 pin voltages (LED cathode voltages) is equal

to the LED control voltage (V_LEDCTL). Power dissipation can be minimized by optimizing the LED control voltage (V_LEDCTL

)

according to the LED current (I_LED).

LED Control Voltage Reference Value (V_{ADIM_P}= V_REG

LED Control

)

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

ISET Resistor

R_ISET[kΩ]

LED Current

I_LED[mA]

Voltage

V_LEDCTL[V]

53.0

30.0

15.1

11.0

22.8

40.3

80.1

110.0

0.53

0.60

0.77

0.90

20 30 40 50 60 70 80 90 100 110 120

I_LED[mA]

Figure 17. V_LEDCTLvs I_LED

2.2 VCC Input Voltage and Number of LED Series

To drive the boost DC/DC converter, the LED must be selected so that the output voltage (VOUT) is higher than the input

voltage (VCC).

ꢄ퐶퐶₍

< ꢄ푂푈ꢋ

< ꢄ푓

)

푀퐴푋

(푀ꢅ푁)

ꢄ퐶퐶

: Input voltage

ꢄ푂푈ꢋ : DC/DC converter output voltage

ꢌ

× ꢌ + ꢄ

)

푀퐴푋

(푀ꢅ푁)

퐿퐸퐷ꢍꢇ퐿(푀ꢅ푁)

: Number of LED series

: LED Vf voltage

: LED control voltage

Select the number of LED series and Vf characteristics that satisfy

the above equation.

ꢄ푓

ꢄ

퐿퐸퐷ꢍꢇ퐿

2.3 LED Variation and Series Number

When operating multiple LED outputs, the LED anode voltages in each row are commonly connected to DC/DC converter

output VOUT. LED pin voltage (LED cathode voltage) in the row where the Vf voltage of the LED is the highest is the lowest,

and this is controlled to be V_LEDCTL. Therefore, the voltage of other LED pin outputs will be higher by the amount of Vf

variation. Select the number of LED series and Vf characteristics so that the LED short protection (V_LEDn≥ 5.0 V) does not

operate.

ꢌ × ꢎꢄ푓

₎− ꢄ푓

₎ꢏ < ꢄ

₎− ꢄ

(

푀퐴푋

푀ꢅ푁

ꢆ퐻ꢐ푅ꢇ 푀ꢅ푁 퐿퐸퐷ꢍꢇ퐿 (푀퐴푋)

ꢄ

ꢆ퐻ꢐ푅ꢇ

: LED short protection voltage

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BD83A24MUF-M

2 DC/DC Converter – continued

VOUT

2.4 Overvoltage Protection Function OVP

Inputs the resistor division of the output voltage VOUT

in the OVP pin. When OVP pin voltage rises the

overvoltage protection detect voltage V_OVP(1.21 V) or

more, the overvoltage protection is activated, and the

switching of DC/DC converter is turned OFF. After that

when OVP pin voltage drops to 1.16 V, OVP is released.

R_OVP2

OVP

+

ꢀ

R_OVP1

1.21 V /

1.16 V

Figure 18. OVP Pin Voltage Setting Sample

{(

)

}

ꢄ푂푈ꢋ_ꢐ푉푃= ꢈ_ꢐ푉푃1+ ꢈ_ꢐ푉푃2∕ ꢈ_ꢐ푉푃1× ꢄ_ꢐ푉푃[V]

ꢄ푂푈ꢋ_ꢐ푉푃

ꢄ_ꢐ푉푃

: DC/DC converter output voltage (VOUT) during overvoltage protection operation

: Overvoltage protection detect voltage

2.5 DC/DC Oscillation Frequency f_OSC

DC/DC oscillation frequency (f_OSC) can be set by connecting R_RTbetween the RT pin and GND. DC/DC oscillation frequency

(f_OSC) is generated in the OSC block. Set the resistor of R_RTreferring to the data and theoretical formula below.

7

푓

: DC/DC oscillation frequency

: Constants determined inside the circuit

: RT pin connecting resistor

: Correction factor

ꢐꢆꢍ

(

)

푓

ꢐꢆꢍ

= ꢂꢃ ∕ ꢈ_푅ꢇ× 훼 [kHz]

ꢂꢃ⁷

ꢈ_푅ꢇ

훼

α is the correction factor. For the relation between f_OSCand R_RTincluding the correction factor, refer to f_OSCvs R_RTbelow.

Note that operation cannot be guaranteed if f_OSCsetting value exceeds the recommended range of 200 kHz to 2420 kHz.

Determine f_OSCsetting value in consideration of the variation in electrical characteristics, variation in R_RT, and ON/OFF of

spread spectrum.

2400

Example of Resistance Value for f_OSCSetting

2200

2000

R_RT[kΩ]

45.0

α

1800

1600

1400

1200

1000

800

1.008

1.000

0.982

0.944

0.837

33.3

20.0

10.0

600

3.8

400

200

4

14

24

34

44

R_RT[kΩ]

Figure 19. f_OSCvs R_RT

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2 DC/DC Converter – continued

2.6 Pulse Addition Function

A pulse addition function is provided to output a stable DC/DC converter output voltage and LED current even when PWM

Duty is low. The output voltage can be held by outputting additional switching of several pulses after the falling edge of the

PWM input signal, and the LED can be turned on normally. When the pulse addition function is not used, set the PLSET

pin to OPEN

V_PWM

0.5 V

V_PLSET

Additional

Pulse Time

t_PLSET

V_SW

VOUT

VOUT Hold

Stable LED Current

I_LED

Figure 20. Pulse Addition Function

The number of additional switching pulses is set in the capacitance value C_PLSETconnected to the PLSET pin. The additional

pulse time t_PLSETis calculated as follows:

푡_{푃퐿ꢆ퐸ꢇ}= ꢂꢃ¹⁰× 퐶_{푃퐿ꢆ퐸ꢇ}[µs]

푡_{푃퐿ꢆ퐸ꢇ}

퐶_{푃퐿ꢆ퐸ꢇ}

: Additional pulse time

: PLSET pin capacitance

1000

100

10

1

0

0.1

1.0

10.0

PLSET Pin Capacitance : C_PLSET[nF]

Figure 21. t_PLSETVS C_PLSET

The additional pulse time required to hold the output voltage VOUT varies depending on various factors such as PWM

frequency, output voltage, output capacitance, LED current, as well as the minimum value of PWM Duty used for dimming.

Contact your sales representative when you request design verification of the required additional pulse time for your usage

conditions.

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2 DC/DC Converter – continued

2.7 External Synchronization / Spread Spectrum Function (SSCG)

Three switching modes can be selected

according to the voltage input to the

SYNC pin.

Mode

1

V_SYNC

Low

DC/DC Switching Frequency

Fixed Frequency Mode Determined by R_RT

Spread Spectrum Mode of the Frequency

Determined by R_RT

2

3

High (= V_REG

Pulse Input

)

Mode to Synchronize with the Frequency Input to

the SYNC Pin

Mode 1:

When the SYNC pin is fixed Low, DC/DC converter switches at a fixed frequency determined by R_RT

.

Mode 2:

By shorting the SYNC pin and the REG pin, operation in spread spectrum mode (SSCG) is enabled. With SSCG, noise

peaks can be reduced by periodically changing the oscillation frequency. The fluctuation range (Δf) of the frequency due to

SSCG is -8 % of the set oscillation frequency from the set oscillation frequency. The oscillation frequency fluctuation period

is 2.3 kHz.

VCC

Δｆ = f_OSCx 0.08

V_EN

V_SYNC

V_PWM

Noise

reduction

1.21 V

Self Diagnosis

Pre-boost

V_OVP

V_SW

Δf = -8 %

f_OSC

f_SSCG= 2.3 kHz

f_OSCx 0.92

f_OSCFrequency

Band

Figure 22. Spread Spectrum Function Timing Chart

Figure 23. Spread Spectrum Function

훥푓

푓

ꢐꢆꢍ

: Fluctuation range of the oscillation frequency by SSCG

: DC/DC oscillation frequency

훥푓 = 푓 × ꢃ.ꢃ8

ꢐꢆꢍ

푓

ꢆꢆꢍ퐺

: The oscillation frequency fluctuation period by SSCG

푓

ꢆꢆꢍ퐺

= ꢑ.3 [kHz]

When not using SSCG function, short the SYNC pin and the GND pin.

SSCG function cannot be turned ON/OFF during operation.

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2.7 External Synchronization / Spread Spectrum Function (SSCG) – continued

Mode 3:

By inputting an external clock signal to the SYNC pin, the internal oscillation frequency can be externally synchronized.

However, note the following points.

·Since Mode is judged during Self Diagnosis (Initial Check), input the clock signal to the SYNC pin prior to turning the EN

pin to High.

·After the clock signal is input to the SYNC pin and the EN pin is turned High, it is not possible to switch between internal

oscillation and external synchronization. Operation may become unstable. After setting to external synchronization (Mode

3), it is possible to change the external synchronization frequency during operation. However, evaluate the LED flickering

due to fluctuations of the output voltage.

·When using external synchronization, SSCG cannot be used.

·For the external synchronization frequency, input a frequency within ±10 % of the theoretical value of the DC/DC oscillation

frequency f_OSCset by the RT pin.

Internal SYNC

4.0 V

1.0 V

V_EN

V_REG

V_SYNC

REG

MODE

Selector

SYNC

SSCG: ON, SYNC: OFF

4.0 V

1.0 V

Internal

V_SYNC

SSCG: OFF, SYNC: ON

SSCG: OFF, SYNC: OFF

7.12 ms

SSCG block

To OSC

Initial Check

Figure 24. Synchronous Signal (V_SYNC) Input and

Mode Check (Initial Check) Timing

Figure 25. SYNC Pin Equivalence Circuit

2.8 LSDET Function

LSDET

OFF

LSDET

ON

LSDET

OFF

When the lowest LED pin voltage among LED pins is 2.4 V

or more, DC/DC converter is turned OFF, and COMP pin

voltage is held. DC/DC converter resumes switching when

the lowest LED pin voltage is less than V_LEDCTLx 1.2.

LSDET function is intended to reduce the voltage quickly

when the output is over boosted. It also prevents the LEDs

from flickering by resuming the switching of DC/DC converter

just before returning to normal operation.

V_PWM

ꢇ

V_SW

ꢄ

①

The LED4 pin becomes open and LED4 pin voltage

becomes 0.3 V or less (Ⓐ).

V_COMP

ꢁ

DC/DC converter output begins boosting further to raise

LED4 pin voltage. In conjunction with this, OVP pin

voltage also rises (Ⓑ).

1.21 V

ꢅ

ꢂ

V_OVP

②

When OVP pin voltage reaches 1.21 V (Ⓒ) due to the

boost of DC/DC converter, the LED open protection is

activated.

When the LED open protection is activated, the LED4

pin that was open is pulled up to REG pin voltage V_REG

inside the IC (Ⓓ).

V_LED1to

V_LED3

ꢆ

V_LEDCTL

V_LEDCTLx 1.2

LSDET function operates because LED4 pin voltage,

which is the lowest LED pin voltage in the LED pins, is

2.4 V or more (Ⓓ).

LSDET function turns OFF DC/DC converters and holds

COMP pin voltage (Ⓔ).

REG Pull Up (V_REG

)

ꢃ

V_LED4

V_LEDCTL

2.4 V

0.3 V

ꢀ

③

④

DC/DC converter turns OFF, the output voltage drops,

and OVP pin voltage also drops (Ⓕ).

LED4

Open

LED4

Open

Detection

When the lowest LED pin voltage is less than V_LEDCTL

x

1.2 (Ⓖ), DC/DC converter resumes switching (Ⓗ).

I_LED1

to

I_LED3

I_LED4

Figure 26. LSDET Function When LEDs are Open

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Function Descriptions – continued

Unless otherwise stated, the value in the sentence is the Typ value.

3 Starting Sequence and Effective Section of Each Protection Function

The timing chart at startup and the effective section of each protection function are shown in the figure below.

①

Power ON

: Input EN pin voltage after the VCC pin voltage is input.

Input the ADIM_P pin voltage at the same time as the EN pin voltage at the latest after inputting

the VCC pin voltage.

②

Self Diagnosis

(Initial check)

: After inputting EN pin voltage, this IC becomes the Self Diagnosis status, determines the channel

to be used, and sets the external synchronization / spread spectrum function, etc. Self Diagnosis is

completed after 7.12 ms, and the diagnostic status is latched.

③

④

Pre-boost

: After Self Diagnosis, pre-boost starts at V_PWM= High, and after 7.12 ms, pre-boost is completed.

Stable operation : The LED current flows according to On Duty of the PWM signal input to the PWM pin. The output

transition section voltage of DC/DC converter with switching turned OFF drops according to the load current.

⑤

Stable state

: When LED pin voltage (the lowest voltage in LED1 to LED4) drops to LED control voltage x 1.2,

DC/DC converter switches again.

VCC

5.5V

V_{ADIM_P}

V_EN

V_REG

V_PWM

4.1 V

(UVLO Release)

ꢋ

After Self Diagnosis

pre-boost starts with V_PWM= High

ꢈ Self Diagnosis

7.12 ms

・Determination of CH to use

・Setting external

synchronization

・Setting spread spectrum

・OVP pin fault detection

・ISET pin fault detection

ꢊ Stable Operation

ꢉ Pre-boost

ꢌ Stable State

7.12 ms

Transition Section

1.21 V

V_OVP

V_SW

I_LED

LED Setting Current Output Section

LED Control Voltage ｘ 1.2

V_LED

LED Control Voltage

During Self Diagnosis

FAIL is Low

V_FAIL

DC/DC Converter Operating Section

Current Driver Operating Section

Under Voltage Lockout（UVLO） Effective when EN = High

Thermal Shutdown REG（TSDREG） Effective when EN = High

Thermal Shutdown LED（TSDLED） Effective when EN = High

Overcurrent Protection（OCPL） Effective when UVLO is released

Overvoltage Protection（OVP） Effective when UVLO is released

Overvoltage Protection（OVP）/ FAIL Flag Effective when LSDET is OFF

Input Overcurrent Protection（OCPH）/ FAIL Flag Effective when UVLO is released

ISET-GND Short Protection / FAIL Flag Effective when Self Diagnosis is completed

LED Open Protection / FAIL Flag Effective when pre-boost is completed

LED Short Protection / FAIL Flag Effective when pre-boost is completed

Short Circuit Protection（SCP） / FAIL Flag Effective when pre-boost is completed

Figure 27. Timing Chart at Startup and Effective Section of Each Protection Function

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3 Starting Sequence and Effective Section of Each Protection Function – continued

Unless otherwise stated, the value in the sentence is the Typ value.

3.1 Self Diagnosis (Initial Check)

The contents of Self Diagnosis are as follows.

3.1.1 LED Pin Used/Unused Check

It is possible to check whether the LED pin is used or not by LED pin voltage at the end of Self Diagnosis. If LED pin

voltage is 0.3 V or more and 2.0 V or less during Self Diagnosis, the LED pin is diagnosed as unused. If it is diagnosed

as unused, the LED pin does not operate and is pulled up to REG pin voltage V_REGinside the IC. To select unused

channels correctly, the capacitance value to be connected to the LED pin should be 470 pF or less.

3.1.2 SYNC Pin Setting Check

ON/OFF of the external synchronization or spread spectrum function can be set by SYNC pin voltage at the end of Self

Diagnosis.

3.1.3 FAIL Pin Connection Check

During Self Diagnosis, the FAIL pin can check the connection between the monitor pin of MCU and the FAIL pin by

turning ON the open drain output (ON resistor = 1 kΩ). Determine the pull up voltage and pull up resistor according to

FAIL detection voltage on the MCU.

3.1.4 ISET-GND Short Check

In Self Diagnosis, ISET-GND Short Check is done under the same conditions as ISET pin fault (ISET-GND short

protection). When ISET-GND short is confirmed, the load switch, DC/DC switching, and current driver are latched OFF.

It is reset when V_EN= Low or UVLO is detected.

3.1.5 OVP Pin Setting Check

Self Diagnosis checks OVP pin setting. The OVP pin during Self Diagnosis is pulled down with IC built-in resistor of 1

MΩ. When an open failure of the OVP pin occurs, OVP pin voltage falls to 0.1 V or less, and the load switch, DC/DC

switching, and the current driver latch OFF. It is reset when V_EN= Low or UVLO is detected.

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Function Descriptions – continued

4 Stopping Sequence and Effective Section of Each Protection Function

The figure below shows the timing chart when stopping and the effective section of each protection function.

⑤

Stable state

: When LED pin voltage (the lowest voltage in LED1 to LED4) drops to the LED control voltage x 1.2,

DC/DC converter is switched again.

⑥

Standby state : Decrease EN pin voltage and ADIM_P pin voltage prior to the VCC pin voltage falling.

Internal circuit is stopped by falling EN pin voltage, and IC is in standby state.

VCC

V_{ADIM_P}

V_EN

V_REG

REG output

function is OFF

when EN = Low

V_PWM

ꢍ Standby State

ꢌ Stable State

V_OVP

V_SW

I_LED

DCDC converter operation is OFF

when EN = Low

Current driver operation is OFF

when EN = Low

V_LED

LED Control Voltage

V_FAIL

DC/DC Converter Operating Section

Current Driver Operating Section

Under Voltage Lockout（UVLO） Effective when EN = High

Thermal Shutdown REG（TSDREG） Effective when EN = High

Thermal Shutdown LED（TSDLED） Effective when EN = High

Overcurrent Protection（OCPL） Effective when UVLO is released

Overvoltage Protection（OVP） Effective when UVLO is released

Overvoltage Protection（OVP）/ FAIL Flag Effective when LSDET is OFF

Input Overcurrent Protection（OCPH）/ FAIL Flag Effective when UVLO is released

ISET-GND Short Protection / FAIL Flag Effective when Self Diagnosis is completed

LED Open Protection / FAIL Flag Effective when pre-boost is completed

LED Short Protection / FAIL Flag Effective when pre-boost is completed

Short Circuit Protection（SCP） / FAIL Flag Effective when pre-boost is completed

By setting EN = Low,

the state is set to standby

and all functions are stopped

Figure 28. Timing Chart at Stopping and Effective Section of Each Protection Function

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PCB Application Circuit Diagram

ꢋ

L1

B+

B-

CM

C_VCC3

C_B2

C_B1

C_CSH

R_CSH3

C_VCC2C_VCC1

R_CSH2R_CSH1

REG

ꢉ

C_REG

C_LDSW

REG

M1

L2

D2

VOUT

EN

R_SYNCU

C_IN1

C_IN2

D1

C_OUT1C_OUT2C_OUT3

C_OUT4

SYNC

REG

R_SYNCD

PWM

LDSW

N.C.

PWM

R_OVP2

R_{ADIM_P}

SYNC

ADIM_P

SW

R_OVP1

EXP-PAD

COMP

RT

PGND

PLSET

C_COMP2

R_COMP1

R_FAIL

ISET

R_RT1

FAIL

REG

FAIL

C_PLSET1C_PLSET2

C_COMP1

VOUT

C_LED1UC_LED2UC_LED3UC_LED4U

R_RT2

R_ISET1

R_ISET2

LED4

LED3

LED2

LED1

R_LED1R_LED2R_LED3R_LED4

C_OVP

C_LED1DC_LED2DC_LED3DC_LED4D

Figure 29. PCB Application Circuit Diagram

①

Place the Input overcurrent detect resistors R_CSH1, R_CSH2,VCC pin capacitors C_VCC1, C_VCC2, and the load switch M1 so that

they are shortest. Also, place the input filters R_CSH3, C_CSHfor detecting the input current close to the CSH pin. They can be

placed on the opposite side of the IC and connected with a via.

②

③

Place the input capacitors C_IN1, C_IN2and the Diode D1 so that they are as short as the components of both the inductor L2

and the load switch M1. Connect the ground of C_IN1, C_IN2, D1 to the PGND pin via EXP-PAD on the surface layer.

To reduce high frequency noises, the wires of the boost "Loop" must be as short as possible. Do not widen the wiring width

more than necessary.

·Place the SW pin, the inductor L2 and the anodes of the diode D2 so that they are the shortest.

·Place the cathode of D2 and the output decoupling capacitors C_OUT1, C_OUT2, C_OUT3, and C_OUT4so that they are the

shortest.

·Place the output decoupling capacitors C_OUT1, C_OUT2, C_OUT3, C_OUT4and the PGND pin so that they are the

shortest.

·Place the IC and each component on the same surface layer of the board and make connections in the same layer.

④

⑤

Place the ground plane on the layer closest to the surface layer where the IC is placed.

Connect the EXP-PAD to the board ground. Wire the ground pattern connected from the EXP-PAD as wide as possible to

improve heat dissipation and connect it to the ground plane with many vias. To ensure heat dissipation according to power

loss, place the required number of thermal vias directly under the EXP-PAD and connect them to the ground plane.

There is no problem if the GND pin, the LGND pin and the PGND pin are connected via the EXP-PAD. However, the power

system ground such as the ground of the output decoupling capacitor and the PGND pin contains the noise component of

the switching frequency. To reduce this noise component, it is recommended to connect to the ground plane using many

vias in the ground pattern around the power system ground.

⑥

⑦

⑧

Place the bypass capacitor (C_REG) between the REG pin and the GND pin as close to pin as possible.

The connection from VOUT to the anode of the LED panel and the connection from the cathode of the LED panel to the

LED1, LED2, LED3, LED4 pins should be as short as possible. Depending on the parasitic inductance component, the LED

current may become unstable.

⑨

Do not run the wiring from the cathode of the LED panel to the LED1, LED2, LED3, LED4 pins in parallel with other active

lines. Also, place the noise reduction capacitors (C_LED1D, C_LED2D, C_LED3D, C_LED4D) so that they are as short as the LED pin.

R_LED1, R_LED2, R_LED3, R_LED4are pull-down resistors connected to the LED pin of unused channel and is required to generate

LED pin voltage that is judged to be unused.

⑩

⑪

⑫

⑬

When using the PWM function, the PWM pin is the active line, so keep it away from other sense lines.

When using the external synchronization function, the SYNC pin is an active line, so keep it away from other sense lines.

When using the DC dimming function, the ADIM_P pin is an active line, so keep it away from other sense lines.

Place R and C connected to the RT pin, the COMP pin, the ADIM_P pin, the ISET pin, the PLSET pin, and the OVP pin as

close to the IC as possible. They can be placed on the opposite side of the IC and connected with a via.

Since OVP pin voltage must be 0.1 V or more during Self Diagnosis, when installing the C_OVP, use about 1000 pF as a guide.

⑭

⑮

When the VCC pin voltage is turned ON setting the EN pin to Low, the voltage between the VCC-LDSW pin may open

momentarily and an inrush current may flow depending on the VCC startup speed and the type of load switch (M1) used.

Be sure to check with the actual application.

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List of External Components

Serial No.

1

Component Name

Component Value

Product Name

Manufacturer

C_B1

CM

-

2

Short

-

3

C_B2

-

4

L1

Short

-

5

C_VCC1

C_VCC2

C_VCC3

R_CSH1

R_CSH2

R_CSH3

C_CSH

C_LDSW

M1

1 μF

GCM21BR71H105KA03

murata

6

-

7

1 μF

GCM21BR71H105KA03

murata

8

15 mΩ

LTR18 Series

Rohm

9

-

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

100 Ω

MCR03 Series

Rohm

100 pF

GCM1882C1H101JA01

murata

-

60 V / 36 A

SQJ457EP

VISHAY

C_IN1

10 μF

GCM32EC71H106KA03L

murata

C_IN2

10 μF

GCM32EC71H106KA03L

murata

D1

60 V / 1 A

RBR1MM60ATF

Rohm

L2

22 μH

CLF10060NIT-220M-D

TDK

D2

60 V / 5 A

RB088LAM-60TF

Rohm

C_OUT1

C_OUT2

C_OUT3

C_OUT4

R_OVP1

R_OVP2

C_OVP

R_FAIL

10 μF

GCM32EC71H106KA03L

murata

10 μF

GCM32EC71H106KA03L

murata

-

33 μF

GYA1H330MCQ1GS

nichicon

10 kΩ

MCR03 Series

Rohm

330 kΩ

MCR03 Series

Rohm

1000 pF

GCM1882C1H102JA01

murata

100 kΩ

MCR03 Series

Rohm

C_PLSET1

C_PLSET2

R_LED1

R_LED2

R_LED3

R_LED4

C_LED1U

C_LED2U

C_LED3U

C_LED4U

C_LED1D

C_LED2D

C_LED3D

C_LED4D

1000 pF

GCM1882C1H102JA01

murata

-

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List of External Components – continued

Serial No.

Component Name

C_REG

Component Value

2.2 μF

-

Product Name

Manufacturer

41

42

43

44

45

46

47

48

49

50

51

GCM21BR71C225KA49

murata

-

R_SYNCU

R_SYNCD

R_RT1

-

100 kΩ

33 kΩ

Short

MCR03 Series

Rohm

-

MCR03 Series

R_RT2

-

R_COMP1

C_COMP1

C_COMP2

R_ISET1

200 Ω

0.1 μF

-

MCR03 Series

Rohm

murata

-

GCM155R11C104KA40D

-

15 kΩ

Short

MCR03 Series

-

Rohm

-

R_ISET2

R_{ADIM_P}

100 kΩ

MCR03 Series

Rohm

Note: The component constants vary depending on the operating conditions and the load used.

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Selection of Components Externally Connected

Unless otherwise stated, the values in sentences are the values in continuous mode.

Select the application components according to the following procedure.

1. Derivating Maximum Input (Inductor) Peak Current I_L(MAX)

2. Selecting Inductor Constant

Feedbacks the L value

NG

3. Setting Input Current Detect Resistor (R_CSH

)

4. Selecting PLSET Capacitance

5. Selecting Output Capacitance

6. Selecting Input Capacitance

7. Setting Overvoltage Protection (OVP)

8. Checking Rated Voltage/Current of Inductor (L), Diode (D1, D2), MOSFET

(M1), Resistor (R_CSH), and Capacitance (C_IN, C_OUT

9. Setting Phase Compensation Circuit

10. Operation Check on Actual Device

)

Figure 30. Application Components Selection Procedure

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Selection of Components Externally Connected – continued

1 Derivating Maximum Input (Inductor) Peak Current I_L(MAX)

VCC

C_VCC

R_CSH

CSH

LDSW

M1

D1

C_IN

L1

D2

SW

VOUT

C_OUT

Figure 31. Output Application Circuit Diagram

1.1 Calculating Maximum Output Voltage VOUT_(MAX)

Calculates VOUT_(MAX)in consideration of LED Vf variation and the number of LED stages.

ꢄ푂푈ꢋ

= ꢄ푓

× ꢌ + ꢄ

(푀퐴푋)

(푀퐴푋) 퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

ꢄ푂푈ꢋ

ꢄ푓

: Maximum output voltage

(푀퐴푋)

: Maximum value of LED Vf voltage

: Number of LED series

: Maximum value of LED control voltage

(푀퐴푋)

ꢌ

ꢄ

퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

1.2 Calculating Maximum Output Current I_OUT(MAX)

: Maximum output current

퐼_{ꢐꢒꢇ(푀퐴푋)}

퐼_{퐿퐸퐷(푀퐴푋)}

퐼_{ꢐꢒꢇ(푀퐴푋)}= 퐼_{퐿퐸퐷(푀퐴푋)}× ꢓ

: Maximum value of LED current per

channel

ꢓ

: Number of LED parallels

1.3 Calculating Maximum Input (Inductor) Peak Current I_L(MAX)

ꢂ

퐼_{퐿(푀퐴푋)}= 퐼_{퐿퐴푉퐺(푀퐴푋)}+ ∆퐼_{퐿(푀퐴푋)}

: Maximum input (inductor) peak

current

퐼_{퐿(푀퐴푋)}

ꢑ

퐼_{퐿퐴푉퐺(푀퐴푋)}: Maximum input (inductor) average

current

퐼_{ꢐꢒꢇ(푀퐴푋)}

: Maximum input (inductor) current

amplitude

: Minimum power supply voltage

∆퐼_{퐿(푀퐴푋)}

퐼_{퐿퐴푉퐺(푀퐴푋)}= ꢄ푂푈ꢋ

×

(푀퐴푋)

휂 × ꢄ퐶퐶_(푀ꢅ푁)

ꢄ퐶퐶_(푀ꢅ푁)

휂

ꢜ_(푀ꢅ푁)

푉ꢍꢍ

푉ꢐꢒꢇ

ꢛ푉ꢍꢍ

(ꢔꢙꢚ) (ꢔꢀꢕ)

1

: Efficiency (about 85 %)

: Minimum value of inductance

(ꢔꢀꢕ)

∆퐼_{퐿(푀퐴푋)}

=

×

ꢗ푆ꢘ(ꢔꢀꢕ)

퐿

ꢖ

푉ꢐꢒꢇ

(ꢔꢙꢚ)

(ꢔꢀꢕ)

: Minimum value of DC/DC

oscillation frequency

푓

ꢐꢆꢍ(푀ꢅ푁)

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Selection of Components Externally Connected – continued

2 Selecting Inductor Constant

To maintain stable continuous operation of the current mode DC/DC converter, the L (inductance) value must satisfy the

following requirements:

푉ꢐꢒꢇꢛ푉ꢍꢍ

15ꢞ.ꢞ푘

ꢄ푂푈ꢋ

ꢄ퐶퐶

ꢜ

: Output voltage

: Power supply voltage

: Inductance value

≤

ꢝ

퐿×10

푅

ꢟ푇

ꢈ_푅ꢇ

: RT pin connecting resistor

Rewriting about L is as follows

(푉ꢐꢒꢇꢛ푉ꢍꢍ)×푅

ꢟ푇

ꢜ ≥

ꢝ

15ꢞ.ꢞ푘×10

Consider the variation of the L value and set it with sufficient margin.

3 Setting Input Current Detect Resistor (R_CSH

)

ꢄ_{ꢐꢍ푃퐻(푀ꢅ푁)}

: Minimum value of input overcurrent

protection detect current

: Minimum value of input overcurrent

protection detect voltage

퐼_{ꢐꢍ푃퐻(푀ꢅ푁)}

=

ꢈ_{ꢍꢆ퐻(푀퐴푋)}

ꢄ_{ꢐꢍ푃퐻(푀ꢅ푁)}

ꢄ퐶퐶_(푀퐴푋)

ꢜ_(푀ꢅ푁)

> 4.ꢃꢠ ꢡ +

× 푡_ꢐꢍ푃퐿

ꢈ_{ꢍꢆ퐻(푀퐴푋)}: Maximum value of input current detect

resistor

푡_ꢐꢍ푃퐿

: OCPL detect delay time (MAX = 150 ns)

Select the R_CSHvalue so that it will be as above.

4 Selecting PLSET Capacitance

푉ꢐꢒꢇ

퐼_{ꢐ퐹퐹퐿ꢐ퐴퐷 푀퐴푋}

=

^(ꢔꢙꢚ)+ 퐼_{ꢆ퐵퐷 푀퐴푋}

( )

ꢗꢢꢣ(ꢔꢀꢕ)

: Maximum value of load current when

PWM = OFF

: Minimum value of overvoltage protection

detect resistor

퐼_{ꢐ퐹퐹퐿ꢐ퐴퐷(푀퐴푋)}

ꢈ_{ꢐ푉푃(푀ꢅ푁)}

(

)

푅

푄_{ꢐ퐹퐹퐿ꢐꢆꢆ 푀퐴푋}= 퐼

₎× 푡_{푃푊푀ꢐ퐹퐹 푀퐴푋}

(

)

(

)

ꢐ퐹퐹퐿ꢐ퐴퐷 푀퐴푋

퐼_{ꢆ퐵퐷(푀퐴푋)}

: Maximum value of rectifier diode leakage

current

: Maximum value of consumed charge

when PWM = OFF

2.5

푄_{푃푊푀푅ꢅꢆ퐸}

=

× 퐼_{ꢐꢒꢇ(푀ꢅ푁)}

ꢗ푆ꢘ(ꢔꢀꢕ)

푄_{ꢐ퐹퐹퐿ꢐꢆꢆ(푀퐴푋)}

ꢖ

푡_{푃푊푀ꢐ퐹퐹(푀퐴푋)}: Maximum value of PWM = OFF time

푉

×ꢍ

ꢣꢤ푆ꢁ푇(ꢔꢀꢕ)

푄_{푃퐿ꢆ퐸ꢇ 푀ꢅ푁}

=

^{ꢣꢤ푆ꢁ푇(ꢔꢀꢕ)}× 퐼_{ꢐꢒꢇ(푀ꢅ푁)}

(

)

푄_{푃푊푀푅ꢅꢆ퐸}

푄_{푃퐿ꢆ퐸ꢇ(푀ꢅ푁)}

: Insufficient charge after PWM rise

: Minimum value of additional pulse output

supply charge

ꢅ

ꢣꢤ푆ꢁ푇(ꢔꢙꢚ)

푄_{푃퐿ꢆ퐸ꢇ 푀ꢅ푁}> 푄

₎+ 푄_{푃푊푀푅ꢅꢆ퐸}

: Minimum value of PLSET threshold

voltage

ꢄ_{푃퐿ꢆ퐸ꢇ(푀ꢅ푁)}

(

)

(

ꢐ퐹퐹퐿ꢐꢆꢆ 푀퐴푋

: Minimum value of PLSET pin capacitance

퐶_{푃퐿ꢆ퐸ꢇ(푀ꢅ푁)}

퐼_{푃퐿ꢆ퐸ꢇ(푀퐴푋)}

Select the C_PLSETvalue so that it will be as above.

: Maximum value of PLSET charging

current

: Minimum output current

퐼_{ꢐꢒꢇ(푀ꢅ푁)}

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Selection of Components Externally Connected – continued

5 Selecting Output Capacitance

The capacitor C_OUTused for the output is determined by the allowable amount of VOUT_PPwhich is the ripple voltage of

VOUT.

푉

×ꢍ

×ꢅ

ꢅ

퐷

)

(

)

ꢣꢤ푆ꢁ푇(ꢔꢙꢚ)

(

)

(

)

ꢣꢤ푆ꢁ푇 ꢔꢙꢚ

ꢗꢥ푇 ꢔꢙꢚ

ꢗꢥ푇 ꢔꢙꢚ × ꢗꢕ ꢔꢙꢚ

ꢄ푂푈ꢋ_{푃푃(푀퐴푋)}

=

+

+ 퐼_{퐿(푀퐴푋)}× ꢈ_{퐸ꢆ푅(푀퐴푋)}

)

ꢅ

×ꢍ

ꢍ

×ꢖ

)

ꢗꢥ푇 ꢔꢀꢕ ꢗ푆ꢘ ꢔꢀꢕ

(

)

(

)

(

ꢣꢤ푆ꢁ푇 ꢔꢀꢕ

ꢗꢥ푇 ꢔꢀꢕ

: Maximum value of VOUT ripple voltage

: Maximum value of PLSET threshold

voltage

퐶_{푃퐿ꢆ퐸ꢇ(푀퐴푋)}: Maximum value of PLSET pin capacitance

ꢄ푂푈ꢋ_{푃푃(푀퐴푋)}

퐼_{푃퐿ꢆ퐸ꢇ(푀ꢅ푁)}

ꢄ_{푃퐿ꢆ퐸ꢇ(푀퐴푋)}

: Minimum value of PLSET charging

current

: Maximum output current

: Maximum value of DCDC-Duty

퐼_{ꢐꢒꢇ(푀퐴푋)}

퐶_{ꢐꢒꢇ(푀ꢅ푁)}

ꢊ_{ꢐ푁(푀퐴푋)}

: Minimum value of output capacitance

: Minimum value of DC/DC oscillation

frequency

푓

ꢐꢆꢍ(푀ꢅ푁)

퐼_{퐿(푀퐴푋)}

: Maximum input (inductor) peak current

ꢈ_{퐸ꢆ푅(푀퐴푋)}

: Maximum value of equivalence serial

resistor for output capacitance C_OUT

The actual VOUT ripple voltage is affected by board layout and component characteristics. Be sure to check on the actual

device and set the capacitance value considering sufficient margin so that it will be within the allowable ripple voltage.

The maximum value of C_OUTthat can be set is 100 μF.

6 Selecting Input Capacitance

A ceramic capacitor with an input capacitance of 10 μF or more and a low ESR is recommended. If a capacitor outside

this range is selected, an excessive ripple voltage may be superimposed on the input voltage, causing IC malfunction.

In addition, the capacitor C_INused for the input is determined by the allowable amount of V_INPPwhich is the ripple voltage

of V_IN.

7 Setting Overvoltage Protection (OVP)

Overvoltage protection (OVP) is set by an external resistors R_OVP1

,

VOUT

R_OVP2. When the OVP pin becomes 1.21 V or more, it detects

overvoltage and stops DC/DC switching. Also, when the OVP pin is

1.21 V or more and the LED1 to LED4 pin voltage is 0.3 V or less,

the open state is detected, and the circuit is latched off (Reference

PROTECT).

R_OVP2

OVP

To prevent an open false detection, the resistor division voltage of

the maximum value of the output voltage must be below the minimum

value of open detection voltage.

+

ꢀ

R_OVP1

1.21 V /

1.16 V

Set R_OVP1, R_OVP2so that they satisfy the following formulas.

Figure 32. OVP Application Circuit Diagram

ꢄ푂푈ꢋ

: Maximum output voltage

ꢈ_ꢐ푉푃1

(푀퐴푋)

ꢄ푂푈ꢋ

×

< ꢄ_{ꢐ푉푃퐷퐸ꢇ(푀ꢅ푁)}

(푀퐴푋)

ꢈ_ꢐ푉푃1

: Overvoltage protection detect

resistor (GND side)

(

)

ꢈ_ꢐ푉푃1+ ꢈ_ꢐ푉푃2

ꢈ_ꢐ푉푃2

: Overvoltage protection detect

resistor (VCC side)

(1)

ꢄ_{ꢐ푉푃퐷퐸ꢇ(푀ꢅ푁)}: Minimum value of overvoltage

e.g.) When using 8 series of LEDs with R_ISET= 15.1 kΩ and Vf = 3.2

V ±0.2 V.

protection detect voltage

ꢈ_ꢅꢆ퐸ꢇ

ꢄ푂푈ꢋ

ꢄ

: Resistor for LED current setting

: Maximum output voltage

( )

= 3.ꢑ + ꢃ.ꢑ × 8 + ꢄ

퐿퐸퐷ꢍꢇ퐿 푀퐴푋

ꢄ푂푈ꢋ

(

)

(

)

푀퐴푋

(푀퐴푋)

: Maximum value of LED control

voltage

퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

= ꢑ8.ꢃꢠ

[V]

ꢈ_ꢐ푉푃1

: Overvoltage protection detect

resistor (GND side)

ꢄ_{ꢐ푉푃퐷퐸ꢇ(푀ꢅ푁)}= ꢂ.ꢂꢦ3 [V]

ꢈ_ꢐ푉푃2

: Overvoltage protection detect

resistor (VCC side)

ꢄ_{ꢐ푉푃퐷퐸ꢇ(푀ꢅ푁)}: Minimum value of overvoltage

If R_OVP1= 20 kΩ, it is necessary to set R_OVP2> 459 kΩ from equation

(1).

protection detect voltage

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Selection of Components Externally Connected – continued

8 Checking Rated Voltage/Current of Inductor (L), Diode (D1, D2), MOSFET (M1), Resistor (R_CSH), and Capacitance

(C_IN, C_OUT

)

(Note 1)

Rated Current

-

Rated Voltage

-

Power Dissipation

> I_OCPH(MAX)²x R_CSH(MIN)

Input Overcurrent Detect Resistor R_CSH

MOSFET M1

(Note 2)

(Note 3)

> I_OCPH(MAX)

> VCC_(MAX)

-

Diode D1^{(Note 3)}

> VCC_(MAX)

-

(Note 4)

Input Capacitance C_IN

Inductor L

-

(Note 5)

> I_A(MAX)

(Note 5)

(Note 6)

Diode D2

> I_A(MAX)

> VOUT_OVP(MAX)

Output Capacitance C_OUT

-

> VOUT_OVP(MAX)

(Note 1) Consider the variation of external components and make setting with sufficient margin.

(Note 2)퐼_{ꢐꢍ푃퐻(푀퐴푋)}= ꢄ_{ꢐꢍ푃퐻(푀퐴푋)}/ꢈ_{ꢍꢆ퐻(푀ꢅ푁)}

(Note 3) If diode D1 is not mounted, ringing will occur on the drain side of MOSFET M1 when MOSFET M1 is turned OFF due to input overcurrent protection.

Ringing causes the drain side of MOSFET M1 to have a negative potential, which may cause the IC to malfunction.

It is recommended to mount the diode D1 when using the input overcurrent protection function

(Note 4) Set so that the rated value of the peak forward surge current > D1 generated current when input overcurrent protection is detected.

When the input overcurrent protection is detected, check the D1 generated current on the actual device.

푉ꢍꢍ_(ꢔꢙꢚ)

(Note 5)퐼_{퐴(푀퐴푋)}= 퐼_{ꢐꢍ푃퐿(푀퐴푋)}

+

× t_OCPL

푡_ꢐꢍ푃퐿

Since the inductor current reaches I_OCPLat startup, the recommended setting is Rated Current > I_{A (MAX)}

However, it is possible to set Rated Current > I_L(MAX)after confirming that no damage occurs in the actual device.

(Note 6) DC reverse voltage

: OCPL detect delay time (MAX = 150 ns)

퐿_(ꢔꢀꢕ)

.

9 Setting Phase Compensation Circuit

About application stability conditions

The stability conditions of the LED pin voltage feedback system are as follows.

(1) Phase delay when gain is 1 (0 dB) is 150° or less (i.e., phase margin is 30° or more)

(2) Frequency (unity gain frequency) when gain is 1 (0 dB) is 1/10 or less of switching frequency

By inserting phase lead fz near the unity gain frequency,

VOUT

stability can be ensured by phase compensation.

The phase delay fp1 is determined by C_OUTand the

output impedance R_L. Each is as follows.

Phase lead 푓푧 = ꢂ/(ꢑ휋 × ꢈ_푃ꢍ× 퐶_푃ꢍ) [Hz]

Phase delay 푓푝ꢂ = ꢂ/(ꢑ휋 × ꢈ_퐿× 퐶_ꢐꢒꢇ

)

[Hz]

LED1 to

LED 4

Error

AMP

* Output impedance calculated by ꢈ_퐿= ꢄ푂푈ꢋ/퐼_ꢐꢒꢇ

COMP

－

Good results can be obtained by setting fz from 1 kHz to

10 kHz. Substitute the value at maximum load for R_L.

+

R_COMP

C_COMP

PWM

COMP

Figure 33. Error AMP Block Application Circuit Diagram

In addition, this setting is a simple calculation and is not calculated exactly, so it may be necessary to make adjustments

on the actual device. Also, these characteristics will change depending on the board layout, load conditions, etc., so

when designing for mass production, make sure to check the actual device before setting.

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Selection of Components Externally Connected – continued

10 Operation Check on Actual Device

Select the constant according to the above procedure and precautions regarding constant setting. In addition, since this

selection is calculated by theoretical calculation, it does not include variations in external components or changes in their

characteristics and is not guaranteed. The parameters that affect the characteristics of the product will change depending

on the actual layout pattern, such as power supply voltage, LED current / number of lamps, inductor, output capacitance,

and switching frequency, so be sure to check with the actual device.

Additional Components for EMC Countermeasure

The figure below shows the examples of EMC countermeasure components.

(1) Capacitor for built-in FET current loop noise reduction

(2) Capacitor for output current loop noise reduction

(3) Capacitor for power line high frequency noise reduction

(4) Low-pass filter for power line noise reduction

(5) Common mode filter for power line noise reduction

(6) Snubber circuit for built-in FET high frequency noise reduction

(7) Snubber circuit for ringing reduction during built-in FET switching

5

4

3

VCC

VREG

EN

CVCC

RCSH

7

M1

PWM

SYNC

ADIM_P

COMP

RT

LDSW

N.C.

PWM

D2

L1

VOUT

COUT

1

SYNC

6

D1

CIN

2

ADIM_P

SW

ROVP2

ROVP1

EXP-PAD

C^COMPRCOMP

PGND

RRT

PLSET

FAIL

CPLSET

RFAIL

RISET

VREG

VFAIL

ISET

Figure 34. Application Circuit Diagram Reference Example (including EMC countermeasure components)

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Precautions for PCB Layout

PCB layout patterns have a significant impact on efficiency and ripple

characteristics, so care must be taken when designing. In the boost

configuration, there is a "Loop" as shown in the figure on the right.

Place the components in the Loop as close as possible (e.g., place

GND of C_OUTand PGND as close together).

VCC

R_CSH

VCC

C_VCC

Also, make sure that the wiring in each loop is as low impedance as

possible.

CSH

Refer to "PCB Application Circuit Diagram" for other detailed

precautions regarding PCB layout.

LDSW

M1

D1

C_IN

L1

D2

SW

VOUT

C_OUT

Loop

PGND

Figure 35. Circuit of DC/DC Block

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BD83A24MUF-M

Power Consumption Calculation Example

The maximum value of IC power consumption can be easily calculated by the following procedure. Take heat dissipation

measures so that the rise in chip temperature due to this power consumption does not exceed Tjmax under the environmental

conditions (ambient temperature, heat dissipation fins, etc.) used by the customer.

ꢧ_{ꢍ(푀퐴푋)}= 퐼_{ꢍꢍ(푀퐴푋)}× ꢄ퐶퐶_(푀ꢅ푁)

+퐶_{ꢅꢆꢆ(푀퐴푋)}× ꢄ_{푅퐸퐺(푀퐴푋)}× 푓

(1) Circuit power

× ꢄ_{푅퐸퐺(푀퐴푋)}

(2) SW FET drive stage power

ꢐꢆꢍ(푀퐴푋)

( )

₎− ꢄ푓 ₎) × ꢌ × ꢓ − ꢂ } × 퐼_{퐿퐸퐷 푀퐴푋}

( ( )

푀퐴푋 푀ꢅ푁

+{ꢄ

₎× ꢓ + (ꢄ푓

(

퐿퐸퐷ꢍꢇ퐿 푀퐴푋

(3) Current driver power

⁾× ꢈ_{ꢐ푁_ꢆ푊(푀퐴푋)}× 퐼_{퐿퐴푉퐺(푀퐴푋)}× 퐼_{퐿퐴푉퐺(푀퐴푋)}

(푉ꢐꢒꢇ ꢛ푉ꢍꢍ

(

)

(

)

ꢔꢙꢚ

ꢔꢀꢕ

+

푉ꢐꢒꢇ

(

)

ꢔꢙꢚ

(4) Power during SW FET ON

ꢂ

+퐼_{퐿퐴푉퐺 푀퐴푋)}× ꢄ푂푈ꢋ

₎× × ꢎꢋ

ꢠ

₎+ ꢋ

₎ꢏ × 푓

(

)

푀퐴푋

푟 푀퐴푋

ꢖ 푀퐴푋 ꢐꢆꢍ 푀퐴푋

(5) SW FET switching power

ꢄ푂푈ꢋ

= ꢄ푓

× ꢌ + ꢄ

(6) Output voltage

(푀퐴푋)

(푀퐴푋) 퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

퐼_{ꢐꢒꢇ(푀퐴푋)}= 퐼_{퐿퐸퐷(푀퐴푋)}× ꢓ

× 퐼_{ꢐꢒꢇ(푀퐴푋)}/(휂 × ꢄ퐶퐶_(푀ꢅ푁)

(7) Output current

퐼_{퐿퐴푉퐺(푀퐴푋)}= ꢄ푂푈ꢋ

)

(8) Input (inductor) average current

(푀퐴푋)

ꢧ_{ꢍ(푀퐴푋)}

: Maximum value of IC power consumption

: Maximum value of circuit current

: Minimum value of power supply voltage

ꢌ

: Number of LED series

퐼_{ꢍꢍ(푀퐴푋)}

ꢄ퐶퐶_(푀ꢅ푁)

퐶_{ꢅꢆꢆ(푀퐴푋)}

퐼_{퐿퐸퐷(푀퐴푋)}

: Maximum value of LED current per channel

: Maximum value of SW pin ON resistor

: Maximum output voltage

ꢈ_{ꢐ푁_ꢆ푊(푀퐴푋)}

: Maximum value of SW FET gating

capacitance

ꢄ푂푈ꢋ

(푀퐴푋)

푓

: Maximum value of DC/DC oscillation

frequency

ꢋ_{푟(푀퐴푋)}

: Maximum value of SW rise time

ꢐꢆꢍ(푀퐴푋)

: Maximum value of reference voltage

: Maximum value of SW fall time

: Maximum value of output current

ꢄ_{푅퐸퐺(푀퐴푋)}

ꢋ

ꢖ(푀퐴푋)

ꢄ

: Maximum value of LED control voltage

: Number of LED parallels

퐼_{ꢐꢒꢇ(푀퐴푋)}

퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

ꢓ

퐼_{퐿퐴푉퐺(푀퐴푋)}: Maximum value of input (inductor) average

current

: Maximum value of LED Vf voltage

: Minimum value of LED Vf voltage

휂

: Efficiency (about 85 %)

ꢄ푓

(푀퐴푋)

ꢄ푓

(푀ꢅ푁)

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BD83A24MUF-M

Power Consumption Calculation Example – continued

Calculate IC power consumption using the following conditions as an example.

퐼_{ꢍꢍ(푀퐴푋)}

ꢄ푓

(푀퐴푋)

Maximum value of circuit current 10 mA

Maximum value of LED Vf voltage 3.4 V

Minimum value of LED Vf voltage 3.0 V

Minimum value of power supply

ꢄ퐶퐶_(푀ꢅ푁)

ꢄ푓

(푀ꢅ푁)

10.5 V

voltage

Maximum value of SW FET gating

capacitance

퐶_{ꢅꢆꢆ(푀퐴푋)}

100 pF

ꢌ

Number of LED series

8 stages

Maximum value of

oscillation frequency

Maximum value of reference

voltage

Maximum value of LED control

voltage

DC/DC

Maximum value of LED current per

channel

Maximum value of SW pin ON

resistor

푓

퐼_{퐿퐸퐷(푀퐴푋)}

ꢈ_{ꢐ푁_ꢆ푊(푀퐴푋)}

ꢋ_{푟(푀퐴푋)}

330 kHz

5.3 V

65 mA

0.4 Ω

20 ns

ꢐꢆꢍ(푀퐴푋)

ꢄ_{푅퐸퐺(푀퐴푋)}

ꢄ

0.74 V

4 rows

SW rise time

퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

ꢋ

ꢓ

Number of LED parallels

SW fall time

20 ns

0.9

ꢖ(푀퐴푋)

휂

Efficiency (about 90 %)

From equation (6),

ꢄ푂푈ꢋ

= ꢄ푓

× ꢌ + ꢄ

(푀퐴푋)

(푀퐴푋) 퐿퐸퐷ꢍꢇ퐿(푀퐴푋)

= 3.4 ꢄ × 8 + ꢃ.ꢦ4 ꢄ

= ꢑꢦ.ꢉ4 [V]

From equation (7),

퐼_{ꢐꢒꢇ(푀퐴푋)}= 퐼_{퐿퐸퐷(푀퐴푋)}× ꢓ

= ꢠꢨ 푚ꢡ × 4

= ꢑꢠꢃ [mA]

Substituting the values obtained in equations (6) and (7) into equation (8),

퐼_{퐿퐴푉퐺(푀퐴푋)}= ꢄ푂푈ꢋ

× 퐼_{ꢐꢒꢇ(푀퐴푋)}/(휂 × ꢄ퐶퐶_(푀ꢅ푁))

(푀퐴푋)

= ꢑꢦ.ꢉ4 ꢄ × ꢑꢠꢃ 푚ꢡ/(ꢃ.ꢉ × ꢂꢃ.ꢨ ꢄ)

= ꢃ.ꢦꢦ [A]

Therefore, the maximum value of IC power consumption P_C(MAX)is calculated as follows:

ꢧ_{ꢍ(푀퐴푋)}= ꢂꢃ 푚ꢡ × ꢂꢃ.ꢨ ꢄ

+ꢂꢃꢃ 푝ꢩ × ꢨ.3 ꢄ × 33ꢃ ꢪꢫ푧 × ꢨ.3 ꢄ

{

(

)

(

)}

+ ꢃ.ꢦ4 ꢄ × 4 + 3.4 ꢄ − 3.ꢃ ꢄ × 8 × 4 − ꢂ × ꢠꢨ 푚ꢡ

{(

)

}

+ ꢑꢦ.ꢉ ꢄ − ꢂꢃ.ꢨ ꢄ /ꢑꢦ.ꢉ ꢄ × ꢃ.4 훺 × ꢃ.ꢦꢦ ꢡ × ꢃ.ꢦꢦ ꢡ

(

)

+ꢃ.ꢦꢦ ꢡ × ꢑꢦ.ꢉ ꢄ/ꢠ × ꢑꢃ 푛푠 + ꢑꢃ 푛푠 × 33ꢃ ꢪꢫ푧

= ꢂ.ꢂꢑ [W]

From thermal resistance θja = 33.8 °C/W, the maximum calorific value Δt_(MAX)can be estimated by the following equation.

훥푡_(푀퐴푋)= ꢧ_{ꢍ(푀퐴푋)}× 휃푗푎 = ꢂ.ꢂꢑ ꢬ × 33.8 ℃/ꢬ = 3ꢦ.ꢉ [°C]

When the ambient temperature is 85 °C, the maximum chip temperature t_C(MAX)is following.

푡_{ꢍ(푀퐴푋)}= 8ꢨ ℃ + 3ꢦ.ꢉ ℃ = ꢂꢑꢑ.ꢉ [°C]

Make sure that t_C(MAX)calculated here is less than Tjmax = 150 °C.

The above is a simple calculation example only. The value of thermal resistance varies depending on the actual board

conditions and layout. Confirm the calculation here as a guide for thermal design.

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BD83A24MUF-M

Application Circuit Example

1 Peripheral Circuit When PMOS Is Not Used

When the load switch M1 is not required, such as when using FUSE on the input side, connect the CSH pin and inductor

L1 and open the LDSW pin.

Also, set FUSE rating to I_FUSEor more.

퐼_퐹ꢒꢆ퐸> 4.ꢃꢠ ꢡ + ^푉ꢍꢍ^(ꢔꢙꢚ)× 푡_ꢐꢍ푃퐿

퐼_퐹ꢒꢆ퐸

: FUSE rated current

퐿

: Maximum value of power supply voltage

: Minimum value of inductance

: OCPL detect delay time (MAX = 150 ns)

ꢄ퐶퐶_(푀퐴푋)

ꢜ_(푀ꢅ푁)

푡_ꢐꢍ푃퐿

(ꢔꢀꢕ)

VREG

VCC

EN

CVCC

Non-

mounted

M1

PWM

SYNC

ADIM_P

COMP

RT

LDSW

N.C.

PWM

D2

L1

VOUT

SYNC

CIN

D1

COUT

ADIM_P

SW

ROVP2

ROVP1

EXP-PAD

C^COMPRCOMP

PGND

RRT

PLSET

FAIL

CPLSET

RFAIL

RISET

VREG

VFAIL

ISET

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BD83A24MUF-M

I/O Equivalence Circuit

REG, VCC

GND, LGND, PGND

EN

VCC

REG

GND

PGND

EN

30 kΩ

360 kΩ

GND

363 kΩ

50 kΩ

150 kΩ

150 kΩ 150 kΩ

GND

LGND

PWM, SYNC, ADIM_P

COMP

RT

REG

10 kΩ

PWM

SYNC

10 kΩ

COMP

RT

ADIM_P

400 Ω

100 kΩ

GND

OVP

REG

GND

ISET

LED1 - LED4

REG

ISET

GND

40 kΩ

LED1

LED2

LED3

LED4

10 kΩ

OVP

10 kΩ

650 kΩ

100 kΩ

2 Ω 200 kΩ

GND

LGND

FAIL

PLSET

SW

REG

SW

10 kΩ

FAIL

PLSET

1 kΩ

PGND

100 kΩ

GND

LDSW

CSH

VCC

1 pF

3 MΩ

25 kΩ

LDSW

GND

CSH

GND

All values are Typ values.

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BD83A24MUF-M

Operational Notes

1. Reverse Connection of Power Supply

Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when

connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply

pins.

2. Power Supply Lines

Design the PCB layout pattern to provide low impedance supply lines. Furthermore, connect a capacitor to ground at

all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic

capacitors.

3. Ground Voltage

Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition.

4. Ground Wiring Pattern

When using both small-signal and large-current ground traces, the two ground traces should be routed separately but

connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal

ground caused by large currents. Also ensure that the ground traces of external components do not cause variations

on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance.

5. Recommended Operating Conditions

The function and operation of the IC are guaranteed within the range specified by the recommended operating

conditions. The characteristic values are guaranteed only under the conditions of each item specified by the electrical

characteristics.

6. Inrush Current

When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow

instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply.

Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing

of connections.

7. Testing on Application Boards

When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject

the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply should

always be turned off completely before connecting or removing it from the test setup during the inspection process. To

prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and

storage.

8. Inter-pin Short and Mounting Errors

Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in

damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin.

Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and

unintentional solder bridge deposited in between pins during assembly to name a few.

9. Unused Input Pins

Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and

extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge

acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause

unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power

supply or ground line.

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BD83A24MUF-M

Operational Notes - continued

10. Regarding the Input Pin of the IC

This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them

isolated. P-N junctions are formed at the intersection of the P layers with the N layers of other elements, creating a

parasitic diode or transistor. For example (refer to figure below):

When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.

When GND > Pin B, the P-N junction operates as a parasitic transistor.

Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual

interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to

operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should be

avoided.

Resistor

Transistor (NPN)

Pin A

Pin B

B

E

C

Pin A

B

C

E

P

P⁺

N

P⁺

P

P⁺

N

Parasitic

Elements

Parasitic

Elements

P Substrate

GND GND

P Substrate

GND

Parasitic

Elements

Parasitic

Elements

N Region

close-by

Figure 36. Example of Monolithic IC Structure

11. Ceramic Capacitor

When using a ceramic capacitor, determine a capacitance value considering the change of capacitance with

temperature and the decrease in nominal capacitance due to DC bias and others.

12. Thermal Shutdown Circuit (TSD)

This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always

be within the IC’s maximum junction temperature rating. If however the rating is exceeded for a continued period, the

junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF power output pins. When the Tj

falls below the TSD threshold, the circuits are automatically restored to normal operation.

Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no

circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat

damage.

13. Over Current Protection Circuit (OCP)

This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This

protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should

not be used in applications characterized by continuous operation or transitioning of the protection circuit.

14. Functional Safety

“ISO 26262 Process Compliant to Support ASIL-*”

A product that has been developed based on an ISO 26262 design process compliant to the ASIL level described in

the datasheet.

“Safety Mechanism is Implemented to Support Functional Safety (ASIL-*)”

A product that has implemented safety mechanism to meet ASIL level requirements described in the datasheet.

“Functional Safety Supportive Automotive Products”

A product that has been developed for automotive use and is capable of supporting safety analysis with regard to the

functional safety.

Note: “ASIL-*” is stands for the ratings of “ASIL-A”, “-B”, “-C” or “-D” specified by each product's datasheet.

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BD83A24MUF-M

Ordering Information

B D 8 3 A 2 4 M U F

-

M E 2

Package

Product rank

MUF: VQFN24FV4040

M: for Automotive

Packaging and forming specification

E2: Embossed tape and reel

Marking Diagram

VQFN24FV4040 (TOP VIEW)

Part Number Marking

LOT Number

D 8 3 A

2 4 M U F

Pin 1 Mark

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BD83A24MUF-M

Physical Dimension and Packing Information

Package Name

VQFN24FV4040

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BD83A24MUF-M

Revision History

Date

Revision

001

Changes

New Release

30.Nov.2022

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Notice

Precaution on using ROHM Products

(Note 1)

1. If you intend to use our Products in devices requiring extremely high reliability (such as medical equipment

,

aircraft/spacecraft, nuclear power controllers, etc.) and whose malfunction or failure may cause loss of human life,

bodily injury or serious damage to property (“Specific Applications”), please consult with the ROHM sales

representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way

responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any

ROHM’s Products for Specific Applications.

(Note1) Medical Equipment Classification of the Specific Applications

JAPAN

USA

EU

CHINA

CLASSⅢ

CLASSⅣ

CLASSⅡb

CLASSⅢ

2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor

products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate

safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which

a failure or malfunction of our Products may cause. The following are examples of safety measures:

[a] Installation of protection circuits or other protective devices to improve system safety

[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure

3. Our Products are not designed under any special or extraordinary environments or conditions, as exemplified below.

Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the

use of any ROHM’s Products under any special or extraordinary environments or conditions. If you intend to use our

Products under any special or extraordinary environments or conditions (as exemplified below), your independent

verification and confirmation of product performance, reliability, etc, prior to use, must be necessary:

[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents

[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust

[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,

H2S, NH3, SO2, and NO2

[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves

[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items

[f] Sealing or coating our Products with resin or other coating materials

[g] Use of our Products without cleaning residue of flux (Exclude cases where no-clean type fluxes is used.

However, recommend sufficiently about the residue.); or Washing our Products by using water or water-soluble

cleaning agents for cleaning residue after soldering

[h] Use of the Products in places subject to dew condensation

4. The Products are not subject to radiation-proof design.

5. Please verify and confirm characteristics of the final or mounted products in using the Products.

6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse, is applied,

confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power

exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect

product performance and reliability.

7. De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in

the range that does not exceed the maximum junction temperature.

8. Confirm that operation temperature is within the specified range described in the product specification.

9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in

this document.

Precaution for Mounting / Circuit board design

1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product

performance and reliability.

2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must

be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,

please consult with the ROHM representative in advance.

For details, please refer to ROHM Mounting specification

Notice-PAA-E

Rev.004

Precautions Regarding Application Examples and External Circuits

1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the

characteristics of the Products and external components, including transient characteristics, as well as static

characteristics.

2. You agree that application notes, reference designs, and associated data and information contained in this document

are presented only as guidance for Products use. Therefore, in case you use such information, you are solely

responsible for it and you must exercise your own independent verification and judgment in the use of such information

contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses

incurred by you or third parties arising from the use of such information.

Precaution for Electrostatic

This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper

caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be

applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,

isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).

Precaution for Storage / Transportation

1. Product performance and soldered connections may deteriorate if the Products are stored in the places where:

[a] the Products are exposed to sea winds or corrosive gases, including Cl₂, H₂S, NH₃, SO₂, and NO₂

[b] the temperature or humidity exceeds those recommended by ROHM

[c] the Products are exposed to direct sunshine or condensation

[d] the Products are exposed to high Electrostatic

2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period

may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is

exceeding the recommended storage time period.

3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads

may occur due to excessive stress applied when dropping of a carton.

4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of

which storage time is exceeding the recommended storage time period.

Precaution for Product Label

A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only.

Precaution for Disposition

When disposing Products please dispose them properly using an authorized industry waste company.

Precaution for Foreign Exchange and Foreign Trade act

Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign

trade act, please consult with ROHM in case of export.

Precaution Regarding Intellectual Property Rights

1. All information and data including but not limited to application example contained in this document is for reference

only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any

other rights of any third party regarding such information or data.

2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the

Products with other articles such as components, circuits, systems or external equipment (including software).

3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any

third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM

will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to

manufacture or sell products containing the Products, subject to the terms and conditions herein.

Other Precaution

1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.

2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written

consent of ROHM.

3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the

Products or this document for any military purposes, including but not limited to, the development of mass-destruction

weapons.

4. The proper names of companies or products described in this document are trademarks or registered trademarks of

ROHM, its affiliated companies or third parties.

Notice-PAA-E

Rev.004


型号：	BD83A24MUF-M (开发中)
厂家：	ROHM
描述：	This IC is a white LED driver for LCD backlight. It has MOS for boost and 4ch current drivers for LED drive, making it ideal for high brightness LED drive. LED pin maximum voltage is 50 V, making it suitable for driving medium LCD panels. The dimming is controlled by the PWM signal and can be set up to 20,000:1@100Hz. It also supports analog dimming and can accommodate even higher brightness ranges by combining with PWM dimming. DC/DC converters can be controlled for boost applications, and the input operating voltage range is 4.5V to 48.0V. CD
文件：	总49页 (文件大小：1918K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

BD83A24MUF-M (开发中) [ROHM]

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