EM7101G [EXCELLIANCE]

Integrated LED current balance control circuit;


型号：	EM7101G
厂家：	Excelliance MOS
描述：	Integrated LED current balance control circuit
文件：	总13页 (文件大小：247K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

EM7101

FEATURES

PIN DIAGRAM: 24 QFN

ꢀ

Integrated LED current balance control circuit

Wide input voltage range

Drives up to 8 strings in parallel

External PWM dimming control

Time-shift PWM phase dimming control

Multi-chip parallel operation for more than 8 LED

strings

ꢀ

MOSFET over-current protection

LED short circuit protection

LED open string protection

Over-temperature protection

Status output

Low standby current

ORDERING INFORMATION

Part Number

EM7101WB

Temp Range

-20°C to +85°C

Note(2), Page 3

Package

24 pin QFN

Lead-Free

24-pin

E-TSSOP

Lead-Free

-20°C to +85°C

Note(2), Page 3

EM7101TE

EM7101G

-20°C to +85°C

Note(2), Page 3

24-pin SOP

Lead-Free

GENERAL DESCRIPTION

EM7101 is a high efficiency DC-DC controller that

drives up to eight strings.

EM7101 provides eight (8) LED current sense inputs

and allows the backlight to remain functioning in the

event that a string(s) is damaged during normal

operation

The IC is able to balance the current flow for each LED

string. It also consumes a low standby current for the

backlight system.

2010/9/20

p.1

EM7101

PIN DESCRIPTION

Pin No

Names

Pin No

I/O(1)

Description

LED Current Sense 4

24QFN 24E-TSSOP 24-SOP

ISEN4

GND

I/O

---

Signal Ground

ISEN5

ISEN6

ISEN7

ISEN8

OVP

I/O

LED Current Sense 5

LED Current Sense 6

LED Current Sense 7

LED Current Sense 8

Over-Voltage Protection

LED Current Resistor Setting

Operation Frequency Resistor

Setting

ISET

I/O

Enable, on/ff control

Power MOSFET Current Sense

No connection

I/O

---

GATE

I/O

Low Side Power MOSFET Driver

5V Regulator Supply For Low

Voltage Blocks

VREF

I/O

PGND

VIN

---

Power Ground

IC Power Supply

Selection Setting To Set 2, 3 or 4

LED Channels

SEL

COMP

SS/CMP

I/O

Multi-Chip Parallel Operation

Soft Start and Control Loop

Compensation

STATUS

PWM

ISEN1

ISEN2

ISEN3

LED Operation Status Output

PWM Dimming Input

LED Current Sense 1

LED Current Sense 2

LED Current Sense 3

I/O

Note(1): I=Input, O=Output, I/O=Input/Output

2010/9/20

p.2

EM7101

ABSOLUTE MAXIMUM RATINGS

LED Operation Status Output

GND,PGND

40.0V

±0.3V

ISEN1/2/3/4/5/6/7/8, CS, EN

VREF, STATUS, OVP, PWM

ISET, SS/CMP, COMP, RT, SEL, GATE

Operating Frequency

-0.3V to 40.0V

-0.3V to 7.0V

-0.3V to(vref +0.3V)

200KHz to 2.5MHz

80mA

ISEN1-8 LED Current

Storage Temperature

-55°C to 150°C

150°C

Operating Junction Temperature

RECOMMENDED OPERATING RANGE

VIN – Input Voltage

4.5V-33V

125°C

Maximum Operating Junction Temp.

ISEN1/2/3/4/5/6/7/8, CS, EN

VREF, STATUS, OVP, PWM

ISET, SS/CMP, COMP, RT, SEL,GATE

Operating Frequency

ISEN1-8 LED Current

≦33V

0.0V to5.5V

0.0V to VREF

500kHz - 2MHz

10mA – 65mA

100Hz – 20kHz

21K ohm to 100K ohm

-20°Cto+85°C

PWM Frequency

RRT

Operating Temperature

Thermal Impedance⁽²⁾

24 pin QFN^(3,4)

θJ-C

5°C/W

θJ-A

38°C/W

86°C/W

24 pin E-TSSOP^(5,6)

15°C/W

13°C/W

24 pin SOP

Note (2): Still air, low effective thermal conductivity board per JESD51-3.

Note (3): QFN bottom pad is recommended to be connected to ground.

Note (4): QFN θ_J-Aunder 50% and 0% bottom pad soldered condition is 43°C/W and 72°C/W respectively. The data

was based on simulation results using a 4 Layer, 76.2 x 114.3 mm²Printed Circuit Board (PCB).

Note (5): E-TSSOP bottom pad is recommended to be connected to ground.

Note (6): E-TSSOP θ_J-Aunder 50% and 0% bottom pad soldered condition is 43°C/W and 72°C/W respectively. The

data was based on simulation results using a 4 Layer, 76.2 x 114.3 mm²Printed Circuit Board (PCB).

2010/9/20

p.3

EM7101

ELECTRICAL CHARACTERISTICS

All specifications below are at T_A=25°C, VIN=24V; RRT=100k unless otherwise noted

Limits

TYP

PARAMETER

VIN Operating Current

VIN Shutdown Current

VIN Stand-By Current

Enable

CONDITIONS

UNITS

MIN

MAX

EN= PWM = 5V

EN= PWM= 0V

EN=5V, PWM=0V

10.2

2.5

150

High

Low

2.45

EN and PWM Logic

0.65

Under Voltage Lockout

Lockout Threshold

Resume Threshold

Reference

VREF_Lockout

VREF_Resume

3.6

3.8

VREF, VIN>6V

Temperature Coefficient

IVREF

5.0

Reference Voltage

100

ppm/°C

VREF Output Current Capability

Drive Logic

GATE Sink Resistance

VIN>6V

3.4

GATE Source Resistance

Minimum MOSFET ON Time

Minimum MOSFET OFF Time

Regulation

Regulation LED Current per Channel

LED Current Balance Rate

Protection

ISET=12Kohm

±1.5

LED Open String Protection Threshold

Shutdown Under Abnormal Condition

LED Short Circuit Protection Threshold

Oscillator

OVP

2.0

3.0

3.5

ISEN1~8

Operation Frequency

RRT=100 KΩ

500

KHz

Temperature Coefficient

ppm/°C

2010/9/20

p.4

EM7101

ELECTRICAL CHARACTERISTICS

All specifications below are at T=25°C, VIN=24V; R_RT=100kΩ unless otherwise noted

Limits

PARAMETER

CONDITIONS

UNITS

MIN

TYP

MAX

Status Output

Sink Resistance

STATUS

100

Ohm

MOSFET Over-Current Protection

NMOS Over-Current Protection

0.52

PARAMETERS GUARANTEED BY DESIGN

Limits

TYP

PARAMETER

CONDITIONS

UNITS

MIN

MAX

VREF

Load Regulation

mV / mA

mV / V

Line Regulation

0.3

Thermal Protection

Lockout Temperature

Resume Temperature

145

110

°C

FUNCTIONAL BLOCK DIAGRAM

ISEN1

ISEN2

ISEN8

Figure 1

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p.5

EM7101

FUNCTIONAL DESCRIPTION

If the voltage of the PWM pin is less than 0.7V for a

period, the IC will be disabled and enter standby mode.

If the voltage of the PWM pin is greater than 2.4V, the

IC will work normally.

Enable

EM7101 is enabled if the voltage of the EN pin is

greater than 2.4V. If the voltage of the EN pin is less

than 0.7V, the IC will be disabled.

Multiple ICs Operation

If the application is more than 8 strings, several

EM7101 ICs can be connected and use the same

power . Refer to application circuit.

Under-voltage lockout

If the voltage of the VREF Pin drops to 3.6V, the IC

output is disabled. When the voltage of the VREF pin

increases to a 3.8V, the IC will work normally . The

VREF has a max source capability of 30mA.

In this kind of application, the COMP pin for each IC

must be shorted together. The N-MOSFET drive signal

for this application is controlled by the Gate pin on the

Master IC. The setting for the Slave IC(s) is almost the

same as the Master IC, but we need to keep Gate pin

floating and short CS pin to GND for Slave IC(s).

Oscillator

The operation frequency can be set by external resistor

connected to RT. Resistor R_RTsets the charging current

for the internal oscillator. The operating frequency can

be calculated by the following equation.

fop [MHz] = --------------

R_RT[k ]

MOSFET OCP

EM7101 provides an over current protection by

monitoring the N-MOSFET current. When the MOSFET

turns on, the voltage at CS pin is going to rise up to

0.5V. At this time, the drive Gate will turn “off”. Then,

the drive Gate will turn “on” as soon as the next cycle

begins.

R_{RT from 20K to 100K is suggested}

LED String Selection`

To set the number of active strings:

ꢁ

ISEN1~8 Active: Connect SEL to GND

ISEN1~6 Active: Connect SEL to VREF

ISEN1~4 Active: Connect SEL to NC

LED Short Circuit Protection

When the voltage at any of the ISEN1-8 pins is over the

threshold voltage of 3.5V during normal operation, the

corresponding string is turned “off” and latched.

Setting LED Current

The LED current is determined by the following

equation:

LED Open String Protection

600

If there is any LED string opened, Vo(output) will rise

up until the voltage of the OVP pin reaches 2.0V . The

IC will ignore the open string(s) and the rest string(s)

will keep working normally.

I_LED[mA] = --------------

R_ISET[k ]

This sensed LED current is for each string.

If all of the LED strings are opened and the voltage of

the OVP pin reaches 2.0V, the MOSFET drive (Gate pin)

will turn off. The IC will shut down and keep latched.

PWM Dimming

It can be set by applying a pulse width signal of 100Hz

to 20kHz to PWM pin. The different duty cycle from

0% to 100% is able to control from minimum to

maximum brightness.

In order to reduce ripple stresses, the EM7101

provides a time-shift PWM dimming .

2010/9/20

p.6

EM7101

Vo(Output) Short protection/ boost diode

open Protection

If the voltage of the OVP pin is less than ~0.1V, the

MOSFET drive(Gate pin) will turn off. This function is

able to protect the converter from damage. The

function will work if the boost diode is open or

Vo(output) is shorted .

OTP

If IC temperature is higher than 140°C, the EM7101 will

turn off . The IC will restart and work normally if the

temperature falls below 110°C.

Shutdown Under Abnormal Condition

If the voltage of the OVP pin is greater than 3.0V, the

IC will shut down and latch. Toggle EN to restart the IC.

This feature can be used for any other protection to

shut down the IC by pulling up OVP pin above 3.0V.

Status Output

If the IC works normally, the STATUS pin is active

high(logic high). And the STATUS pin will become logic

low if there is any of the following conditions

happened:

ꢂ

OVP

OTP

Any of LED strings is open

LED short protection

2010/9/20

p.7

EM7101

REFERENCE APPLICATION CIRCUIT USING 24 PIN QFN

Figure 3: EM7101 application circuit

2010/9/20

p.8

EM7101

ISEN2-8

ISEN2-7

ISEN2-6

ISEN2-5

R201

10K

PWM2

ISEN2-4

ISEN2-3

ISEN2-2

ISEN2-1

5 4 3 2 1

R203

12K

R204

100K

PAD

ISEN3

OVP2

ISEN2

OVP

ISET

ISEN1

PWM

EM7101

R202

10K

EN2

STATUS

SS/CMP

R205

R206

100K

100

C203

470n

13 14 15 16 17 18

R208

R207

＊

C202

2.2u

ISEN1-8

ISEN1-7

ISEN1-6

ISEN1-5

R101

10K

PWM1

ISEN1-4

ISEN1-3

ISEN1-2

ISEN1-1

R103

R104

100K

PAD

ISEN3

ISEN2

12K

OVP1

OVP

ISET

ISEN1

PWM

EM7101

R102

10K

EN1

STATUS

SS/CMP

R105

100

R106

100K

14 15 16 17 18

C103

R108

470n

R107

＊

C102

2.2u

STATUS

10uH

VIN

VOUT

SS15

2.2u/50V

OVP2

OVP1

EMB55N06G

4.7K

50m

51K

＊： OPTION

Figure 4:Application Circuit Using 2-EM7101 Driving 16LED Strings

2010/9/20

p.9

EM7101

Ordering & Marking Information:

Device Name: EM7101TE for E-TSSOP-24

Device Name

Lot No.

EM7101TE

XXXXXXXXX

XXXXXX

Date code

Device Name: EM7101 for QFN-24

Device Name

Lot No.

EM7101

XXXXXX

Date code

Device Name: EM7101G for SOP-24

Device Name

EM7101G

XXXXXXXXX

XXXXXX

Lot No.

Date code

2010/9/20

p.10

EM7101

Outline Drawing

E-TSSOP-24

Exposed Diepad

Dimension

Min.

0.00

0.8

0.19

3.70

2.28

7.70

7.80

7.90

4.30

4.40

4.50

0.45

0.60

0.75

0°

NOR

1.00

1.05

0.127BSC

6.4BSC

0.65BSC

1.00REF

Max.

1.2

0.15

0.30

4.62

2.85

8°

2010/9/20

p.11

EM7101

Outline Drawing

QFN-24

Dimension

Min.

0.203REF

0.70

0.75

0.80

0.18

0.25

0.30

3.90

4.0

1.90

2.00

2.10

3.90

4.00

4.10

1.90

2.00

2.10

0.30

0.40

0.50

NOM.

0.02

0.05

0.50BSC

Max.

4.10

2010/9/20

p.12

EM7101

Outline Drawing

SOP-24

Dimension

Min.

0.1

0.2

0.3

2.26

1.4

0°

2.36

2.54

2.64

0.35

7.4

7.5

7.6

0.51

0.25

0.23

10.00

10.31

10.65

NOR

15.4

1.27

Max.

0.48

0.31

1.02

0.75

8°

2010/9/20

p.13

EM7101G [EXCELLIANCE]

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