SC804AMLTRT_技术文档

SC804A

Fully Integrated 4.4V Lithium-Ion

Battery Charger System with Timer

PRELIMINARY

POWER MANAGEMENT

Description

Features

ꢀFully integrated charger with FET pass transistor,

reverse-blocking diode, sense resistor, timer, and

thermal protection

The SC804A is a fully integrated full-feature, single cell

constant-current/constant-voltage (CC/CV) 4.4V Lithium-

Ion battery charger. With an integrated timer and

complete charge control algorithm, the SC804A is ideal for

stand-alone charger applications. The SC804A contains

programmable pre-charge, fast-charge and termination

current settings. The SC804A can be programmed to

terminate charging based on the output current or the

time-out of the programmable timer. The fast charge

current is typically set with an external resistor, but it can

also be adjusted by applying an analog voltage to the AFC

pin. This feature allows use of a microcontroller to set

charging current via a DAC output.

ꢀBattery voltage controlled to 1% accuracy

ꢀProgrammable precharge, fastcharge & termination

current over wide range, with analog current control

reference input for design ﬂexibility

ꢀUp to 1.5A continuous charge current

ꢀInput voltage range from 3V to 14V

ꢀSoft-start reduces start-of-charge adapter

load transients

ꢀNTC thermistor sense input and adjustable cold

temperature threshold

The SC804A’s 14V input voltage range eliminates the

need for additional protection circuitry required by other

ꢀAdjustable 2 - 6 hour programmable charge timer

5V chargers to protect against faulty adapters. The ꢀ0.1μA battery drain current in shutdown and monitor

SC804A also incorporates an under-voltage lockout falling

threshold of 3V so that charging will continue if the input

supply goes into a current-limited mode.

modes

ꢀSmall 4mm x 4mm 16 lead MLPQ package

ꢀOver-current protection in all modes

ꢀOver-voltage protection

Reference ground and battery sense inputs are provided

to eliminate voltage drops during charging due to high

charging currents.

ꢀRemote Kelvin sensing at the battery terminals

ꢀStatus indicators for charger-present, charger-active,

over-voltage fault, and error notiﬁcation

The output voltage to the battery is controlled to within

1% of the programmed voltage. The SC804A can also

Applications

ꢀCellular phones

ꢀPDAs

ꢀHandheld meters

ꢀCharging stations

function as a general purpose current source or as a

ꢀHandheld computers

ꢀDigital cameras

ꢀProgrammable current

source

Typical Application Circuit

current source for charging nickel-cadmium (NiCd) and

nickel-metal-hydride (NiMH) batteries.

Typical Application Circuit

Charger VIN

14

11

VCC

13

CPB

10

12

2

OV_FLT

OVPB

IPRGM

NTC

CHRGB

RTIM

CTO

Red

Green

3

7

4

8

6

5

R3

C1

2.2 μF

1

ITERM

FLTB

BSEN

VOUT

AFC

RT

NTC

16

15

9

R5

R6

R1

R2

GND

C2

RGND

2.2μF

Battery

SC804A

R4

ERROR

DAC ISET

July 18, 2007

1

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SC804A

PRELIMINARY

POWER MANAGEMENT

Absolute Maximum Ratings

Exceeding the speciﬁcations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters speciﬁed in the

DRAFT

Electrical Characteristics section is not implied.

Parameter

Symbol

Maximum

Units

VCC, CTO, NTC to GND

-0.3 to 14.0

V

VOUT, BSEN, RTIM, AFC, IPRGM, CPB, CHRGB, OVPB,

ITERM, FLTB, to GND

-0.3 to +6.0

V

RGND to GND

-0.3 to 0.3

V

A

VOUT Output Current

I_VOUT

Pd

1.5

Power Dissipation MLP (Derate 20mW/°C above 85°C)

Thermal Impedance, Junction to Ambient⁽¹⁾

Junction Temperature

2

48

W

θ_JA

°C/W

°C

T_J

150

Operating Ambient Temperature Range

IR Reﬂow Temperature

T_A

-40 to +85

260

°C

T_LEAD

T_STG

°C

Storage Temperature Range

VOUT short to GND

-65 to 150

Continuous

2

°C

ESD Protection Level⁽²⁾

V_ESD

kV

Notes:

1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.

2) Tested according to JEDEC standard JESD22-A11 4-B.

Electrical Characteristics

Unless otherwise noted: VCC = 4.75V - 5.25V. Typical values are at T_A= 25°C Min and Max are for -40°C < T_A< +85°C unless noted.

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Operating Voltage

VCC_OP

4.28

5.0

6.22⁽¹⁾

V

Charging begins when

threshold is exceeded

VCC UVLO Rising Threshold

VCC UVLO Falling Threshold

VT_UVLOR

VT_UVLOF

VT_OVPR

3.88

2.86

6.63

4.08

3.06

6.94

4.28

3.26

7.40

V

Charging continues until

threshold is reached

VCC OVP

Rising Threshold

VCC OVP

Falling Threshold

VT_OVPF

VT_OVPH

ICC_DIS

6.22

200

6.63

350

1.9

7.00

600

V

VCC OVP Hysteresis

Operating Current

mV

Shutdown Mode - CHRGB, CPB,

OVPB, FLTB off NTC = 0V

mA

Charging Mode - CHRGB, CPB,

OVPB, FLTB off NTC = 2.5V

ICC_CHG

2.0

2

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Electrical Characteristics (Cont.)

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Battery Leakage Current

(VOUT and BSEN)

VCC = 0V,

VOUT = BSEN = 4.5V

ILEAK_BAT

0.1

2

μA

Regulated Constant

Voltage

V_CV

0°C ≤ T_J≤ 125°C

4.314

22

4.357

30

4.40

38

V

RGND Output Accuracy

VOUT = VOUT_NOM+ ∆RGND

V_RGND

RGND - GND = 30mV

mV

RGND Current

I_RGND

I_PREQ

I_TERM

RGND = 0V

35

μA

Battery Pre-Charge Current

R_ITERM= 499Ω, 0°C ≤ T_J≤ 125°C

270

300

330

mA

Battery Termination

Current

R_ITERM= 499Ω, 0°C ≤ T_J≤ 125°C

300

815

405

1

mA

V

Battery Fast-Charge

Current

R_PRGM= 1.87kΩ, VOUT = 3.8V

0°C ≤ T_J≤ 125°C

I_FAST

753

364

878

447

AFC DAC

Fast-Charge Current

R_PRGM= 1.87kΩ, V(AFC) = 0.75V

0°C ≤ T_J≤ 125°C

I_DACADJ

VT_AFC

V_ITERM

V_IPRGM

VT_PreQ

VT_ReQ

T_OT

AFC Enable/Disable

Threshold

VCC - V_AFC> VT_AFCdisables

Analog Fast Charge

ITERM Regulated

Voltage

1.45

2.9

1.557

3.01

100

150

1.66

3.11

140

V

IPROG Regulated

Voltage

V

V_BATPrecharge

Threshold

0°C ≤ T_J≤ 125°C

V_CV- V_BSEN, 0°C ≤ T_A≤ 85°C

Hysteresis = 10°C

V

V_BATRecharge

Threshold

60

mV

°C

Over-Temperature

Shutdown

3

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Electrical Characteristics (Cont.)

Parameter

Symbol

Conditions

Min

Typ

Max

Units

VT_NTCDIS

SC804A Disabled

0.3

0.6

0.8

V

NTC Hot V_TH

Applies to falling threshold

4.3V ≤ VCC ≤ 6.5V

29

30

31

% of

VCC

VT_NTCH

1.45

73.4

1.50

74.4

1.55

75.4

V

at VCC = 5V

NTC Cold V_TH, V_CTO= 0V

Applies to rising threshold

4.3V ≤ VCC ≤ 6.5V

% of

VCC

VT_NTCC

3.67

3.72

50

3.77

V

at VCC = 5V

NTC Hot & Cold VT_NTCx

hysteresis

(VT_NTCxRising - VT_NTCxFalling)

NTC Thresholds

VT_NTCHYS

mV

Applies to internal NTC thresholds

CTO Voltage (Adjustable NTC

Cold Rising Threshold) Setting

Range⁽²⁾, -40°C ≤ T_A≤ 25°C(NTC

Cold Rising Threshold is VT_NTCC

when CTO tied to GND)

% of

VCC

50

90

70

V_CTO

Threshold Error⁽³⁾,

-40°C ≤ T_A≤ 25°C

-70

mV

Internal hysteresis on CTO

(V_CTORising - V_CTOFalling)

Applies to externally set

NTC cold threshold

VT_CTOHYS

50

3.5V ≤ VOUT ≤ VCC - 150mV

0°C ≤ T_J≤ 125°C

Adjust Mode BSEN Voltage

V_BSEN-ADJ

3.189

3.217

3.253

400

V

Adjust Mode Enable Voltage,

VOUT-BSEN

V_ADJEN

V_ADJDIS

V_RTIM

3.5V ≤ VOUT ≤ VCC - 150mV

R_RTIM= 37.4kΩ

mV

V

Adjust Mode Disable

Voltage, VOUT-BSEN

150

1.450

0.65

External RTIM

Regulation Voltage

1.557

0.85

1.1

1.660

V_RTIM≤ VT_TIMER

Timer Disable

Threshold

VT_TIMER

VT_INTTS

V

disables internal timer

VCC-V_RTIM> VT_INTTS

selects internal timer

Internal Timer Select

V

4

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Electrical Characteristics (Cont.)

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Pre-Charge Fault

Time-out

R_RTIM= 37.4kΩ

RTIM pulled to VCC

-20%

-35%

51

44

+20%

+35%

T_PreQF

min

Complete Charge

Time-out

R_RTIM= 37.4kΩ

RTIM pulled to VCC

-20%

-35%

3.37

2.89

+20%

+35%

T_QCOMP

hr

CHRGB On

CHRGB Off

CPB On

V_CHRGB

I_CHRGB

V_CPB

Load = 5mA

Leakage Current, V = 5V

Load = 5mA

0.5

1

V

μA

V

CPB Off

I_CPB

Leakage Current, V = 5V

Load = 5mA

μA

V

OVPB On

OVPB Off

FLTB On

V_OVPB

I_OVPB

V_FLTB

I_FLTB

Leakage Current, V = 5V

Load = 5mA

μA

V

FLTB Off

Leakage Current, V = 5V

μA

Notes:

1) VCC_OP Max is the “Maximum Vsupply” as deﬁned in EIA/JEDEC Standard No. 78, paragraph 2.11.

2) The absolute voltage on CTO must not exceed 6.0V to ensure normal operation.

3) The threshold error is tested at V_CTOmin and max only.

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SC804A

PRELIMINARY

POWER MANAGEMENT

Ordering Information

Pin Conﬁguration

DRAFT

DEVICE

PACKAGE

16

15

14

13

SC804AMLTRT⁽¹⁾

MLPQ -16⁽²⁾

RTIM

BSEN

CTO

1

2

3

4

12

11

10

9

TOP VIEW

CPB

SC804EVB

Evaluation Board2(

)

CHRGB

IPRGM

ITERM

Notes:

T

AFC

1) Available in tape and reel packaging only. A reel contains 3000

devices.

5

6

7

8

2) Available in lead-free packaging only. This product is fully WEEE

and RoHS compliant.

MLPQ16: 4X4 16 LEAD

Pin Descriptions

Pin #

Pin Name

Pin Function

Battery voltage sense. Connect to battery positive terminal for Kelvin voltage sensing, VOUT otherwise.

Do not leave open.

1

BSEN

Cold Temperature Offset. Adjustable NTC input high voltage (cold temperature) threshold. When the pin

2

CTO

is connected to GND the NTC high voltage threshold defaults to VT_NTCC×V_VCC

.

3

4

5

6

IPRGM

ITERM

RGND

GND

Charger current program pin for fast-charge mode. Requires a resistor to GND to program fast-charge current.

Charger termination current program pin. Requires a resistor to GND to program pre-charge and termination current.

Reference ground. Connect to battery’s negative terminal for Kelvin voltage sensing, GND otherwise. Do not leave open.

Ground.

Input for battery NTC thermistor network. Voltage between VT_NTCH×V_VCC, normally the hot threshold, and the CTO voltage

(VT_NTCC×V_VCCif CTO is tied to GND), normally the cold threshold, enables charging. Voltages outside this range suspend

charging and drive FLTB pin active (low). Voltage below VT_NTCDIS(nominally 0.6V) disables the SC804A and resets the

charge timer (with FLTB pin inactive).

7

NTC

8

9

FLTB

AFC

Open drain fault indicator. Active low when a fault condition occurs.

Analog Fast Charge input. Connect to a DAC for analog control of fast charge current level, connect to VCC

to disable this feature. Do not leave open.

Open drain charge status indicator. Active low when the charger is on and the output current exceeds the

termination current setting, high impedance when I_VOUT< ITERM.

10

11

CHRGB

CPB

Open drain charger-present indicator. Active low when VCC exceeds UVLO.

Programmable timer input pin. Connect to VCC to select the default time-out of 3 hrs., connect to GND

to disable timer, or connect an external resistor to GND to program the time-out period.

12

RTIM

13

14

15

16

OVPB

VCC

Open drain over-voltage indicator. Active low when an input over-voltage fault occurs.

Input supply pin. Connect to adapter power.

VOUT

Charger output. Connect to battery.

THERMAL

PAD

Thermal-conduction pad on bottom of the package. Solder directly to the ground plane with multiple

thermal vias to all other ground planes.

T

6

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Block Diagram

14

VCC

1

9

BSEN

AFC

V

CV (VBSEN-ADJ in Adj. Mode)

Reference

Voltages

Fast-Charge Ref

Pre- Charge Ref

VT_NTCCVT_NTCH

5

RGND

Pre-Charge On

Fast-Charge On

Over-Temp

Under-Voltage

Over-Voltage

Cold

Threshold

VOUT

15

16

2

6

7

CTO

GND

NTC

Offset

Control

Timer

V

ITERM

NTC

Interface

ITERM

IPRGM

4

3

RTIM 12

V

IPRGM

10

11

8

CHRGB

CPB

FLTB

OVPB

13

Figure 1 - SC804A Functional Block Diagram

7

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Applications Information

General Operation

Fast-Charge Mode (CC)

The SC804A can be conﬁgured independently with respect The fast-charge CC (Constant Current) mode is active when

to fast-charge and termination current, output voltage, the battery voltage is above VT_PreQand less than V_CV. The

and timing, depending on the application. A typical fast-charge current can be set to a maximum of 1.5A and

charging cycle is described below. Details on alternative is selected by the program resistor on the IPRGM pin. The

applications and output programmability are covered in voltage on this pin will represent the current through the

the individual sections.

battery, enabling a microprocessor via an analog-to-digital

converter (ADC) to monitor battery current by sensing the

voltage on the IPRGM pin. The equation to set the fast-

charge current is given by:

The charging cycle begins when the power adapter is

connected to the device. The SC804A performs glitch

ﬁltering on the VCC input and initiates a charge cycle

when V_VCCis greater than the under-voltage lockout (UVLO)

rising threshold voltage. If the battery voltage is less than

the pre-charge threshold level, the SC804A will output the

pre-charge current. Once the pre-charge threshold voltage

is exceeded, the SC804A enters fast-charge constant

current (CC) mode. When the battery voltage reaches its

ﬁnal value, the charger enters the constant voltage (CV)

mode. In this mode the output current decreases as the

battery continues to charge until the termination current

level is reached. The CHRGB output turns off when IOUT

drops below the termination current. If the charge timer

is active, the SC804A continues to hold the battery in

CV charge mode until the timer expires. When the timer

expires the charger enters the monitor mode where the

output remains off until the voltage at VOUT drops by

VT_ReQ. At this point a new charge cycle is initiated.

V_{IPRGM_Typ}

× 1000

FCI =

R_IPRGM

The superior fast-charge current accuracy of the SC804A

is obtained by use of a patented* polarity-switched

(i.e., chopped) current sense ampliﬁer to nullify current

measurement offset errors.

Compliance with the absolute maximum output current

I

_VOUTMAX, allowing for current regulation tolerance, requires

that R_IPRGMbe no smaller than 1.05kΩ nominal. R_IPRGMcan

be as large as 12.1kΩ, for a nominal FCI as small as 130

mA, but must exceed PCI by at least 80mA. Note that for

a given program resistor the current into the battery in CV

mode can be determined by replacing V_{IPRGM_Typ}with the

actual voltage on the IPRGM pin in the above equation.

The CC current can also be modiﬁed by applying an analog

voltage to the AFC pin as described below.

Pre-Charge Mode

Pre-charge mode is automatically enabled whenever

the battery voltage is below the pre-charge threshold

voltage, VT_PreQ. It is used to limit the power dissipation and

precondition the battery for fast charging. The pre-charge

current value is determined by the resistor on the ITERM

pin. The pre-charge current is programmable from 50mA

to 350mA. The equation to select the pre-charge current

is given by:

Analog Fast Charge (AFC Pin)

Many applications require more than one current setting

for fast-charge. This behavior is obtained in the SC804A

using the AFC function. When the AFC pin is connected

to VCC the device behaves as described in the previous

section. When the AFC pin is driven by an analog voltage

between 0V and (V_VCC-1.0)V, the SC804A automatically

uses this pin voltage to set the maximum fast-charge

current according to the following equation:

V_{ITERM_Typ}

PCI =

× 100

R_ITERM

whereV_{ITERM_Typ}designatesthetypicalvalueofV_ITERM. When

the timer is enabled there is also a maximum allowed pre-

charge duration. If the pre-charge time exceeds 25% of

the total charge cycle the charger will turn off due to a

pre-charge fault. This fault is cleared when VCC is toggled

V_AFC

FCI =

× 1000

R_IPRGM

This adjustment to the fast charge current is obtained

or the output voltage rises above VT_PreQ

.

by replacing the ﬁxed V_IPRGMreference voltage with the

*US Patent 6,836,095.

8

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SC804A

PRELIMINARY

POWER MANAGEMENT

Applications Information (Cont.)

AFC voltage. (Note that AFC voltages above V

produce I_VOUTexceeding that programmed as per the Fast- capacity. The RTIM pin is connected to VCC to select the

Charge Mode (CC) section.) For any applied AFC voltage, internal timer, and to GND to disable the timer.

_{in the event of a faulty battery and to maximize}D_chR_arA_gF_inT_g

will

IPRGM

FCI must not drop below 130mA, and FCI must always

remain at least 80mA greater than PCI.

Connecting a resistor between RTIM and GND will program

the total charge time according to the following equation:

R_RTIM

————

3.08

1

× ———

3600

Termination Current

Charge time =

(

)

Once the battery voltage reaches V_CVthe SC804A will

transition from constant current mode to constant voltage

mode. The current through the battery will decrease while

the voltage remains constant as the battery becomes fully

charged. When the current falls below the programmed

termination current set by the termination resistor

connected to the ITERM pin, the SC804A will disable

CHRGB. If the timer is enabled the output will continue

to ﬂoat-charge in CV mode until the timer expires. If the

timer is disabled, the output will turn off as soon as the

termination current level is reached. The equation to set

the termination current is given by:

With charge time expressed in hours. The timer is

programmable over the range of 2 to 6 hours. The internal

timer selection results in a charge time of 3 hours. The

SC804A will automatically turn off the output when the

charge timer times out.

NTC Interface

The NTC pin provides an interface to a battery pack

Negative Temperature Coefﬁcient (NTC) thermistor. The

typical NTC network has a ﬁxed resistor from VCC to the

NTC pin, and the battery pack NTC thermistor connected

from the NTC pin to ground. In this conﬁguration, an

increasing battery temperature produces a decreasing

NTC pin voltage, and a decreasing battery temperature

produces an increasing NTC pin voltage.

V_{ITERM_Typ}

ITERM =

× 100

R_ITERM

ITERM can be programmed to be as high as 300mA or as

low as 50mA, though accuracy is not guaranteed below

100mA. ITERM must be programmed to be less than FCI

for correct operation of the charge cycle.

This conﬁguration is shown in the typical application

schematic on page 1 of this datasheet. When the NTC

voltage from the divider is greater than the high (cold)

threshold or less than the low (hot) threshold, the SC804A

suspendsthechargecyclebyturningofftheoutput, halting

(but not resetting) the charge timer, and indicating a fault

on the FLTB pin. Hysteresis is included for both high and

low NTC thresholds to avoid chatter at the NTC trip points.

When the NTC pin voltage returns to the valid range, the

SC804A automatically resumes the charge cycle. The

charge timer will time-out when the SC804A output on-

time exceeds the timer setting regardless of how long it

has been disabled due to the NTC temperature.

Monitor Mode

When a charge cycle is complete, the SC804A output

turns off and the device enters monitor mode. If the

voltage of the battery falls below the recharge threshold

(V_CV- V_ReQ), the charger will clear the charge timer and

re-initiate a charge cycle. The maximum current drain of

the battery during monitor mode will be no more than 1μA

over temperature. The status of the charger output as a

function of the timer and IOUT is tabulated below.

An input voltage between VT_NTCH×V_VCCand the CTO input

voltage V_CTO(VT_NTCC×V if CTO is tied to GND) enables

charging. An input vo^Vlt^Ca^Cge outside this range suspends

charging and drives FLTB pin active (low). The internal

NTC thresholds of VT_NTCHand VT_NTCCwere designed to

work with standard thermistors available from numerous

vendors.

Timer

Iout

N/A

Output State

T < Timeout

T > Timeout

Disabled

On

Off

N/A

< Itermination

Charge Timer

NTC pin voltage below VT_NTCDIS(nominally 0.6V) disables

The timer on the SC804A has two functions: to protect

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SC804A

PRELIMINARY

POWER MANAGEMENT

Applications Information (Cont.)

DRAFT

the SC804A and resets the charge timer (with the FLTB or R3 = 2.333×R_HOT= 13.624kΩ exactly. The closest 1%

pin inactive). The NTC pin can be pulled down to ground standard nominal value is R3 = 13.7kΩ.

by an external n-channel FET transistor or processor GPIO

Step 2: Verify acceptable thermistor self heating. In

general, lower values of RT provide more noise immunity

for the NTC voltage, but at the expense of bias current

from the input adapter and power dissipation in the NTC

network. The dissipation constant is the power rating of

the thermistor resulting in a 1^oC self heating error. The

greatest self-heating occurs at low thermistor resistance

(at high temperature). Since temperature sensing

accuracy matters only at the charging temperature range

thresholds, self heating is assessed only at the worst case

high temperature threshold of +40^oC.

to disable or reset the SC804A.

Note that the response of the SC804A to NTC pin voltage

above the high threshold and below the low threshold

is the same. Thus it is possible to conﬁgure the NTC

network with the battery pack thermistor between NTC

and VCC, and a ﬁxed resistor between NTC and ground.

This conﬁguration may be useful if it is desired to reset the

charge timer (and the CHRGB output) when the battery

pack is removed (so the ﬁxed resistor pulls the NTC pin to

ground) while VCC is present.

For V_VCC= 5V, the 40^oC NTC network current I_{NTC_HOT}

=

V_VCC(R3 + R_HOT) = 0.246mA. Power dissipation in the

Cold Temperature Offset (CTO)

/

thermistor at this temperature, P_HOT= R_HOT× (I_{NTC_HOT})²=

0.38mW, for self heating of approximately 0.13^oC. The

actual high temperature threshold will thus be lower by

0.13^oC. This self-heating error is usually acceptable. If

it is not, then a thermistor with a greater R_HOTmust be

chosen.

The voltage applied to the CTO pin sets the NTC high

voltage (normally the cold temperature threshold) for the

NTC input. The default NTC high threshold (VT_NTCC×V_VCC

can be selected by connecting the CTO pin to ground. If

it is desired to change this threshold, the voltage on the

CTO pin can be set between 0.5×V_VCCand 0.9×V_VCC

)

.

Step 3: Determine the desired high (cold) threshold.

Compute the NTC network resistor divider voltage, as a

function of V_VCC, at the cold temperature threshold.

This feature is especially useful if a single PCB design

is needed to satisfy similar applications with different

requirements. The temperature range for normal charging

can be adjusted by adjusting resistor values on a divider

network without changing the NTC thermistor, which

is often enclosed in the battery pack. An example of a

typical application is shown in Figure 2.

VCC × R_COLD

NTC_COLD

=

= 0.6591 × VCC

R3 + R_COLD

Step 4: Conﬁgure CTO. If NTC_COLDis sufﬁciently close

to the default cold threshold (VT_NTCC×V_VCC), then simply

connect CTO to ground, disabling the CTO function, to

complete the design. But in this example it is not, so the

voltage on CTO must be set to 0.6591×V_VCC. The simple

resistive voltage divider network of Figure 2 can be used

to obtain the desired CTO voltage.

NTC/CTO Design Example

The following example assumes the NTC network

conﬁgurationofFigure2, withaﬁxedresistorR3connected

between NTC and VCC, and a battery NTC thermistor

RT connected between NTC and ground. The battery

temperature range over which charging is permitted is

0^oC through 40^oC. The datasheet for the selected NTC

thermistor indicates that RT = 5.839kΩ at 40^oC, at RT =

26.49kΩ at 0^oC, with a dissipation constant DC = 3mW.

Designate R_HOT= 5.839kΩ and R_COLD= 26.49kΩ.

V_CTO= NTC_COLD

VCC × R_CT2

= 0.6591 × VCC =

R_CT1+ R_CT2

or

Step 1: Select R3. For the normal (NTC thermistor to

ground) conﬁguration, solve the NTC network voltage

divider for R3 to place the NTC voltage at 0.3×VCC when

R_CT1

1 0.6591

=

= 0.5172

RT = R_HOT

.

R_CT2

0.6591

VCC × R_HOT

R3 + R_HOT

0.3 × VCC =

10

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SC804A

PRELIMINARY

POWER MANAGEMENT

Applications Information (Cont.)

The choice of R_CT1and R_CT2is somewhat arbitrary. The

_{internal voltage references as VOUT pulls VCC}D_doR_wA_nF_tT_o

simplest approach is to pick one and compute the other. near, or below, V_CV, creating a reduced output regulation

A good choice here is R_CT1= 115kΩ, and R_CT2= 221kΩ, as voltage approximately 200mV below VCC. Thus VCC

these standard 1% tolerance values produce the closest cannot be pulled down below VOUT + 200mV. The dropout

match to the desired voltage divider ratio. With these voltage will be larger than 200mV whenever the minimum

resistor nominal values,

path resistance multiplied by the output current exceeds

200mV, but it cannot be smaller than 200mV.

VCC × R_CT2

V_CTO

=

= 0.6577 × VCC

This greatest-of-two-limit dropout voltage behavior is

evident in the dropout voltage typical performance plot.

R

_CT1+ R_CT2

When operating in Adjust Mode (next section), the

regulated minimum dropout voltage depends on the

programmed VOUT regulation voltage, and dropout also

varies with the actual output voltage during CC charging.

See Figure 4 for an illustration of dropout voltage data.

which is, nominally, only 0.2% below the target value of

0.6591×V_VCC. The CTO network will present a load of only

15μA to a 5V charging adapter. The nominal impedance

presented to the CTO pin is R_CT1|| R_CT2= 75.6kΩ. Any

impedance on the order of 100kΩ (or less) is acceptable.

Adjust Mode

Remote Kelvin Sensing at the Battery

The SC804A can be conﬁgured for an output voltage

other than V_CVusing Adjust (ADJ) Mode. In Adjust Mode

the output voltage is determined by an external resistor

divider from VOUT to BSEN. When BSEN is connected in

this fashion, V_VOUT(during Constant Voltage (CV) charging)

will be controlled such that the voltage at the BSEN pin

The BSEN pin provides the positive Kelvin sensing voltage

feedback to the CV ampliﬁer and should be connected as

close to the battery + terminal as possible. Likewise, the

RGND pin should be connected directly to the negative

terminal of the battery. This allows the designer great

ﬂexibility in PCB layout and achieves greater accuracy

by sensing the battery voltage directly at the battery

terminals. When laying out the PCB, the designer should

route the BSEN and RGND trace directly to the battery

connection terminals, rather than just to the VOUT and

GND pins on the device.

(V_BSEN) is the reference voltage V_BSEN-ADJ

.

The output voltage can be set to any voltage desired by

an appropriate choice of divider network resistors, within

the following limits. When the SC804A is programmed for

adjust mode, V_VOUTis required to be 150mV less than V_VCC

,

and V_VOUTis required to be 400mV greater than V_BSEN

.

V_VOUTwithin 150mV of V_BSENguarantees normal mode

operation. This implies that, for BSEN used as a Kelvin

sense of battery voltage, the product of the fast charge

current and the charge path resistance from VOUT to the

Kelvin sense point should not exceed 150mV to ensure

normal mode operation.

Dropout Voltage

Dropout voltage is the smallest achievable difference

voltage between VCC and VOUT under a particular

operating condition. Dropout voltage is encountered

during CC charging whenever the current limit of the

charging adapter is less than the SC804A FCI programmed

current. In this case, the adapter voltage (the SC804A

input voltage) will be pulled down to the battery voltage

(the SC804A output voltage) plus the dropout voltage.

The SC804A Adjust Mode schematic is shown in Figures

3a and 3b. Referring to these schematics, the equation

for setting the output voltage is:

R11

R12

Dropout voltage is the larger of two values: (1) the I-R

component, which is the output current multiplied by the

minimum VCC-to-VOUT path resistance (which is highly

temperature dependent), and (2) a regulated minimum

difference voltage, which is output voltage dependent

but is independent of the output current. The regulated

minimum dropout voltage results from the collapse of

VOUT = V_{BSEN-ADJ_TYP}x ( 1 +

)

The capacitor C3 across R8 in the feedback network

introduces zero-pole frequency compensation for stability.

Place the zero according to the following equation to

ensure stability:

1

R11 × C3 =

2ꢀ × 100kHz

11

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Applications Information (Cont.)

Charger VIN

14

13

3

11

10

12

2

VCC

CPB

CHRGB

RTIM

CTO

OV_FLT

OVP

Red

Green

R3

IPRGM

NTC

C1

2.2 μF

7

R_CT1

R_CT2

4

1

ITERM

FLTB

GND

BSEN

VOUT

AFC

RT

NTC

8

16

15

9

R5

R6

6

R1

R2

5

RGND

SC804A

C2

R4

2.2μF

ERROR

Figure 2 - Application Circuit with AFC Disabled, and with NTC and CTO Resistor Networks

Charger VIN

14

13

3

11

10

12

2

VCC

CPB

CHRGB

RTIM

CTO

OV_FLT

OVP

Red

Green

R3

IPRGM

NTC

C1

2.2 μF

7

4

1

ITERM

FLTB

GND

BSEN

VOUT

AFC

RT

NTC

R11

8

16

15

9

R5

R6

6

R1

R2

5

RGND

C3

C2

2.2μF

SC804A

R4

R12

ERROR

Figure 3a - Application Circuit for Adjust Mode

Charger VIN

14

13

3

11

10

12

2

VCC

CPB

CHRGB

RTIM

CTO

OV_FLT

OVP

Red

Green

R3

IPRGM

NTC

C1

2.2 μF

7

4

1

ITERM

FLTB

GND

BSEN

VOUT

AFC

RT

NTC

R11

8

16

15

9

R5

R6

6

R1

R2

R4

R12

5

RGND

C3

C2

2.2μF

SC804A

ERROR

Figure 3b - Application Circuit for Adjust Mode, with Adapter-only Voltage Sensing

12

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Applications Information (Cont.)

Overcurrent and Max Temperature Protection

Overcurrentprotectionisinherentinallmodesofoperation.

When the device is in charge mode the output is current-

limited to either the pre-charge current limit value or the

fast charge current limit value depending on the voltage

at the output. Max die temperature protection is also

included. This feature allows the SC804A to operate

with maximum power dissipation by disabling the output

current when the die temperature reaches the maximum

operating temperature. The result is that the SC804A will

operate as a pulse charger in extreme power dissipation

applications, delivering the maximum allowable output

current while regulating the internal die temperature to a

safe level.

0.8

0.6

0.4

0.2

3.2

3.4

3.6

3.8

4

4.2

4.4

4.6

Output voltage, V

Figure 4 - Adjust Mode Minimum Dropout Voltage

The actual dropout voltage is the greater of the Minimum Dropout

Voltage at various programmed V_CVand instantaneous VOUT

voltages (shown here, with several programmed V_CVvoltages

indicated in the ﬁgure by ‘o’), and the IR drop due to the product

of IOUT and R_DS-ON(not shown here). Adjust mode operation is

ensured for any IOUT current at programmed V_CVvoltages up to

approximately 4.41V.

Indicator Flags

There are four indicator outputs/LED drivers ont he

SC804A; CPB (Charger Present), CHRGB (Charge Active),

OVPB (Over Voltage Fault), and FLTB (Fault). These outputs

are all active-low; open drain NMOS drivers capable of

sinking up to 10mA. The following table deﬁnes each

indicator’s output state.

NOTE: WhenusingAdjustModetoprogramaCVregulation

voltage greater than V_CV, care must be taken when CC

charging with a charging adapter operating in current

limit. Adapter current-limited operation occurs when

the adapter current limit is less than the programmed

SC804A fast charge current, such that the adapter voltage

is pulled down to V_VOUTplus the SC804A dropout voltage.

A low adapter current limit multiplied by the low minimum

path resistance of the main pass transistor and current

sense resistor (as low as 290mΩ total at extremely low

temperature) can result in a voltage drop from VCC to

VOUT of less than 150mV if the Adjust Mode CV regulation

voltage is programmed above V_CV+ 50mV. If V_VCC- V_VOUT

< 150mV, Adjust Mode may not operate correctly. Adjust

Mode will operate correctly whenever the programmed

VOUT CV voltage is less than V_CV+ 50mV, regardless of the

adapter current limit, because the regulated minimum

dropout voltage is always greater than 150mV in this

case. It will also operate correctly with an adapter current

limit greater than 550 mA, regardless of the programmed

output voltage, because the I-R dropout voltage will

exceed 150mV at even the lowest speciﬁed operating

temperature. Normal mode (that is, not Adjust Mode) has

a regulated minimum dropout voltage of approximately

200mV, which is constant for any V_VOUT, and so operates

correctly for any adapter current limit.

FLAG

CPB

ON

OFF

UVLO < VCC < OVP

IOUT > ITERM

VCC > OVP

Input out of range

IOUT < ITERM

VCC < OVP

CHRGB

OVPB

VCC > OVP

VCC UVLO

NTC Temp Fault

Pre-Charge Time-out

(OT (Tj > 150°C)

Normal Operation or

NTC Disable

FLTB

The CPB output can be used as a VCC-present indicator.

Regardless of teh state of NTC, the CPB output reﬂects

the VCC voltage. When V_CCis between the UVLO and OVP

thresholds the CPB output is low. If V_CCis outside these

limits, this output is high impedance.

The CHRGB output indicates the charging status. When

the output current is greater than ITERM, CHRGB is low.

CHRGB is high impedance when IOUT is less than ITERM.

The CHRGB output is latched during the charge cycle

when the output current is less than ITERM. This latch is

reset when the battery enters a recharge cycle, or if NTC

or VCC are toggled.

13

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SC804A

PRELIMINARY

POWER MANAGEMENT

Charge Mode Timing Diagram

DRAFT

The OVPB signal is an active-low output that signals when

the input voltage exceeds the OVP threshold. When the

voltage on VCC is less than the OVP threshold voltage

this output is high impedance.

and pre-charge timeout. When any of these conditions

occurs the FLTB output goes low; otherwise it remains

high impedance.

The FLTB output is activated when the device experiences

a fault condition. This output can be used to notify the

system controller of a fault condition when connected to

an interrupt input, or it can be used like CPB and CHRGB

to drive an indicator LED. There are ﬁve fault modes

signaled by FLTB: input over-voltage, input under-voltage,

NTC temperature out of range, max die temperature (OT),

Capacitor Selection

Low cost, low ESR ceramic capacitors such as the X5R and

X7R dielectric material types are recommended for use with

the SC804A. The output capacitance range is 1ꢀF to 4.7ꢀF.

The input capacitor is typically between 0.1ꢀF to 2.2ꢀF, but

larger values will not degrade performance

UVLO

VCC

VT_PreQ

Re-Charge

Threshold

VOUT

Fast Charge

Termination

Current

Soft Start

Pre-Charge

IOUT

CV Mode

CC Mode

CPB

CHRGB

On

Off

On

Off

On

Hold

TIMER

FLTB

Off

On

Off

NTC

Fault

Figure 5 - Charge Mode Timing

14

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

State Diagram

Over-Voltage, Under-Voltage or

Over-Temperature will force the

SC804A into Shutdown Mode

from any state.

Shutdown Mod:e

VOUT &IOUT off,

OVP > VCC> UVLO

En =Hi

CHRGB High Z,

CPB Low.

Yes

CC = Constant Current

CV = Constant Voltage

Soft Start Vout

CHRGB Low

Timer

Enabled?

Yes

Start Timer

Start Pre- Charge

Yes

Soft Start CC Mode

V

OUT > VTPreQ

OUT =IPREQ

IOUT =IFAST

I

Time>TMAX/4

Yes

V

OUT =VCV

Pre- Charge

Timeout Fault

FLTB goes low.

Cleared by

Yes

Start CV Mode

VBAT> VT^PreQ

or Re- cycle VCC

IOUT <ITERM

low temp> NTC Temp> high temp

Yes

CHRGB High Z

NTC out of Range Fault

FLTB goes active low

Timer is frozen

Charge resumes when NTC

Temperature is valid

Timer

Enabled?

Yes

Monitor Mode

Time>T^MAX

VOUT off

Yes

Float Charge Mode

OUT

V

CV

ReQ

<V - V

VOUT =VCV

15

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Typical Charge Cycle

Evaluation Board conﬁgured for internal timer, 1.5V on IPRGM = 843mA, 1.5V on ITERM = 300mA, VCC = 5.0V, Li-Ion

battery capacity = 850mAh. A 237Ω load resistor (18mA at a battery voltage of 4.36V) was applied to the battery fol-

lowing completion of precharge, to slowly discharge the battery following charge timer timeout to illustrate a recharge

cycle. The alphabetic markers indicate the following: (a) precharge; (b) fast charge, or Constant Current (CC) charg-

ing; (c) Constant Voltage (CV) charging; (d) termination; (e) CV (“ﬂoat”) charging until charge timer timeout; (f) charge

timer timeout; (g) discharge of the battery due to 18mA load; (h) recharge cycle initiated when battery voltage drops

below the recharge threshold.

5

g

c

e

f

4.36

4

b

3.5

3

a

2.5

2

h

d

1.5

1

0.5

0

30

60

90

120

150

180

210

240

270

300

330

360

Time (minutes)

900

800

700

600

500

400

300

200

100

0

b

c

a

h

f

0

30

60

90

120

150

180

210

240

270

300

330

360

Time (minutes)

16

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Typical Characteristics

VOUT V_CVLine Regulation vs. Load, T = +25°C

VOUT V_CVLoad Regulation vs. Line, T = +25°C

4.356

4.354

4.352

4.350

4.348

4.346

4.344

4.342

4.340

4.338

VCC = 5.0V

Iout = 500mA

4.354

VCC = 5.5V

4.352

4.350

Iout = 750mA

4.348

VCC = 6.0V

Iout = 1000mA

4.346

4.344

VCC = 6.5V

4.342

Iout = 1500mA

4.340

4.338

5.00

5.20

5.40

5.60

5.80

6.00

6.20

6.40

500

750

1000

1250

1500

VIN (V)

IOUT (mA)

VOUT V_CVRegulation vs. Temperature,

VCC = 5.0V, IOUT = 800mA

IOUT Line Regulation vs. Temperature,

RPRGM = 1.87kΩ

4.360

4.358

4.356

4.354

4.352

4.350

4.348

840

836

832

828

824

820

816

T = +85°C

T = +25°C

T = -40°C

5.00

5.25

5.50

5.75

6.00

6.25

6.50

-50

-25

0

25

50

75

100

Ambient Temperature, °C

VCC, V

Precharge and Termination Current vs.

ITERM Resistance

IOUT vs. IPRGM Resistance, T = +25°C

1800

1600

1400

1200

1000

800

400.0

350.0

300.0

250.0

200.0

150.0

100.0

50.0

600

400

0.0

0.3

0.5

0.7

0.9

1.1

0

0.5

1

1.5

2

2.5

1/Riprgm, 1/k

Ω

1/RIPRGM, 1/k

Ω

17

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Typical Characteristics (Cont.)

Dropout Voltage vs. IOUT

Rds-on vs. IOUT

0.900

0.620

0.570

0.520

0.470

0.420

0.370

0.320

0.270

T_J= +125°C

0.800

T_J= +125°C

0.700

T_J= +85°C

0.600

T_J= +85°C

0.500

0.400

0.300

T_J= +25°C

T_J= -40°C

T_J= +25°C

0.200

T_J= - 40°C

0.100

400

600

800

1000

1200

1400

1600

400

600

800

1000

1200

1400

1600

IOUT (mA)

AFC Operation, RPRGM = 1.87kΩ

1200

1000

800

600

400

200

0

AFC Pin Tied to VCC

Actual AFC Response

Ideal AFC Response

0

0.5

1

1.5

2

V_AFC, V

18

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Evaluation Board Schematic

CHARGER+

CHARGER-

RTIM

C1

1

2

2.2u

R9

R10

1

2

1

<NM>

JP6

JP1

D1

1

2

R1

VOUT

2

1

2

1

D2

D3

D4

390

R15

1

2

1

R11

0

C2

2.2u

C3

<NM>

1

2

GND

CTO

1

37.4k

1

2

3

4

12

BSEN

CTO

RTIM

CPB

3

2

1

R2

JP2

JP3

JP5

11

10

9

1

2

1

2

U1

SC804A

390

R3

1

2

IPRGM

ITERM

CHRGB

AFC

390

R13

JP7

IPRGM

ITERM

2

1

2

1

100k

R12

<NM>

R6

1.87k

R5

499

R4

JP4

1

2

1

2

R14

390

2

1

2

1

RGND

0

R8

R7

1

2

GND

1

<NM>

R16

10k

3

1

NTC

POT_3296W-105

Evaluation Board Gerber Plot,Top/Bottom Views

19

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Outline Drawing - MLPQ-16

DIMENSIONS

INCHES MILLIMETERS

DIM

A

MIN NOM MAX MIN NOM MAX

A

D

-

.031

A1 .000

.040 0.80

.002 0.00

1.00

0.05

-

B

E

-

(.008)

-

(0.20)

A2

b

D

.010 .012 .014 0.25 0.30 0.35

.153 .157 .161 3.90 4.00 4.10

PIN 1

INDICATOR

(LASER MARK)

D1 .079 .085 .089 2.00 2.15 2.25

.153 .157 .161 3.90 4.00 4.10

E1 .079 .085 .089 2.00 2.15 2.25

E

e

.026 BSC

0.65 BSC

L

N

.012 .016 .020 0.30 0.40 0.50

16

aaa

bbb

.003

.004

0.08

0.10

A2

A

SEATING

PLANE

aaa

C

A1

C

D1

e/2

LxN

E/2

E1

2

1

N

e

bxN

bbb

C

A B

D/2

NOTES:

1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).

2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.

Marking Information

804A

yyww

xxxxx

xxxx

yyww = Date Code (Example: 0552)

xxxxx xxxx = Semtech Lot Number

(Example: E9010 01-1)

20

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SC804A

PRELIMINARY

DRAFT

POWER MANAGEMENT

Land Pattern - MLPQ-16

K

DIMENSIONS

DIM

INCHES

MILLIMETERS

(.156)

.122

.091

.026

.016

.033

.189

(3.95)

3.10

2.30

0.65

0.40

0.85

4.80

C

G

H

K

P

X

Y

Z

2x Z

H

2x G

Y

2x (C)

X

P

NOTES:

1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.

CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR

COMPANY'S MANUFACTURING GUIDELINES ARE MET.

Contact Information

Semtech Corporation

Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 FAX (805)498-3804

21

www.semtech.com


型号：	SC804AMLTRT
厂家：	SEMTECH CORPORATION
描述：	Fully Integrated 4.4V Lithium-Ion Battery Charger System with Timer 完全集成的4.4V锂离子电池充电器系统具有定时器电源电路电池电源管理电路输入元件
文件：	总21页 (文件大小：539K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SC804AMLTRT [SEMTECH]

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