LTC1729CS8-8.2#TRPBF

Final Electrical Specifications

LTC1729 Series

Li-Ion Battery Charger

Termination Controllers

October 1999

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DESCRIPTION

FEATURES

The LTC^®1729 series is a family of smart termination

controllers for lithium-ion battery chargers. These ICs

providetricklechargepreconditioning,temperaturecharge

qualification, time or charge current termination, auto-

matic charger and battery detection and status output.

Combining the LTC1729 series part with the LT^®1510

(1.5A), LT1769 (2A), LT1511 (3A) and LT1505 (>4A)

step-down chargers is a simple operation. Connecting six

pins from the LTC1729 series part to the step-down

chargers completes the integration. The LTC1729 termi-

nation controllers are also compatible with step-down/

step-up(SEPIC)chargers,includingtheLT1512(2Aswitch)

and LT1513 (3A switch).

■

Trickle Charge Preconditioning If Cell <2.7V

■

Charging Enabled When 0°C < T < 50°C

■

Built-In Termination: 3-Hour Time-Out

■

C/10 Detection with Status Indicator

■

Automatic Charger Present Detection

■

Automatic Battery Present Detection

■

1- or 2-Cell, 4.1V/Cell or 4.2V/Cell Options

■

Precision Internal 0.2% Voltage Feedback Divider

■

Compatible with LT1505/LT1510/LT1511/

LT1512/LT1513/LT1769

Small Footprint/Low Profile

■

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APPLICATIONS

■

Cellular Phones

The LTC1729 series is available in the 8-pin MSOP and SO

packages.

■

PDAs

■

Cradle Chargers

Camcorders

■

, LTC and LT are registered trademarks of Linear Technology Corporation.

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TYPICAL APPLICATION

MBRM120T3

INPUT POWER

8.2V TO 20V

MBRM120T3

V

SW

CC

+

1µF

6.19k

LT1510-5

PROG

C

IN

*

0.22µF

300Ω

10µF

L1**

BOOST

GND

10µH

1k

V

C

MMBD914L

0.1µF

OVP

SENSE

BAT

+

C

***

OUT

4.2V

22µF

1

2

3

4

8

7

6

5

0.1µF

OVP

BAT

V

CC

1.4k

†

D1

CHARGE STATUS

V

C

1µF

LTC1729-4.2

SENSE STATUS

200Ω

1729 F01

GND

NTC

10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE

NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT

* TOKIN OR MARCON SURFACE MOUNT

** COILTRONICS TP3-100, 10µH, 2.2mm HEIGHT

(0.8A CHARGING CURRENT)

OPTION: TIE RESISTOR TO STATUS FOR

CHARGE TERMINATION AT

LOW CHARGING CURRENT

COILTRONICS TP1 SERIES, 10µH, 1.8mm

HEIGHT (<0.5A CHARGING CURRENT)

*** PANASONIC EEFCD1B220

†

LUMEX SML-LX0805GW-TR

Figure 1. 500kHz Li-Ion Cell Phone Charger (0.8A)

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.

1

LTC1729 Series

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(Note 1)

ABSOLUTE MAXIMUM RATINGS

V_CC......................................................................... 30V

SENSE, V_BAT, NTC .................................... –0.3V to 15V

V_C............................................................. –0.3V to 15V

OVP ............................................................ –0.3V to 5V

STATUS .................................................... –0.3V to 30V

Operating Temperature Range .................... 0°C to 70°C

Storage Temperature Range ................ –65°C to 150°C

Lead Temperature (Soldering, 10 sec)................. 300°C

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PACKAGE/ORDER INFORMATION

ORDER PART

NUMBER

ORDER PART

NUMBER

TOP VIEW

OVP

BAT

1

2

3

4

8

7

6

5

V

CC

C

OVP

BAT

SENSE

GND

1

2

3

4

8 V

7 V

6 STATUS

5 NTC

CC

C

LTC1729CMS8-4.1

LTC1729CMS8-4.2

LTC1729CMS8-8.2

LTC1729CMS8-8.4

LTC1729CS8-4.1

LTC1729CS8-4.2

LTC1729CS8-8.2

LTC1729CS8-8.4

SENSE

GND

STATUS

NTC

MS8 PACKAGE

8-LEAD PLASTIC MSOP

S8 PACKAGE

8-LEAD PLASTIC SO

S8 PART MARKING

MS8 PART MARKING

T_JMAX= 150°C, θ_JA= 200°C/ W

T_JMAX= 150°C, θ_JA= 150°C/ W

LTLY

LTJH

LTLZ

LTJG

172941

172942

172982

172984

Consult factory for Industrial and Military grade parts.

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C, V_IN= 8V.

A

LTC1729-4.1/LTC1729-4.2

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

DC CHARACTERISTICS

I

V

Supply Current

V

= 5V (Below UVLO)

= 8V, 200µA Pull-Up on V

●

1

5

12

2.0

21

µA

mA

VIN

CC

IN

(4.5V) No Bat

1.0

10

0.5

1.4

17

3.0

BAT

= 8V, V

= 2.5V Trickle

= 3.5V Charge

BAT

●

5.0

V

Undervoltage Lockout High

Undervoltage Lockout Low

5.5

5.0

6.5

6.0

7.5

7.0

V

LKOH

LKOL

VBAT

IN

I

Current

V

IN

V

IN

V

IN

V

IN

= 5V (Below UVLO), V = 4.2V

BAT

●

–1

40

–19

– 0.1

73

–16

1

µA

mA

BAT

= 8V, V

= 4.25V No Bat

= 2.5V Trickle

= 3.5V Charge

120

–9.5

–0.5

BAT

●

–2.7

–1.3

mA

V

BAT

Clamp

No Bat (External 200µA Pull-Up on V )

BAT

4.25

4.5

4.75

V

CLAMP

High V

Threshold

High Going Threshold

Low Going Threshold

●

4.25

4.51

4.50

4.75

V

MAX

BAT

V

Low V

High Going Threshold

Low Going Threshold

●

2.55

2.45

2.7

2.6

2.85

2.75

V

MIN

BAT

I

SENSE Pin Current

Charge State, V

= 3V

●

85

100

115

µA

SENSE

V

SENSE Pin C/10 Offset

Charge State, V = (V

– V )

SENSE

±1

±2.5

mV

C10

BAT

2

LTC1729 Series

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C, V_IN= 8V.

A

LTC1729-4.1/LTC1729-4.2

SYMBOL

PARAMETER

CONDITIONS

= 1V

MIN

TYP

MAX

UNITS

µA

I

NTC Pin Current

V

NTC

●

90

100

110

NTC

V

Thermistor Pin Reset Threshold

Thermistor Pin Hot Hold Threshold

0.160

0.206

0.240

V

NTC-RESET

High Going Threshold

Low Going Threshold

●

0.460

0.380

0.486

0.405

0.510

0.430

V

NTC-HOT

V

Thermistor Pin Cold Hold Threshold

OVP Pin Voltage

High Going Threshold

Low Going Threshold

●

2.70

2.10

2.79

2.23

2.90

2.35

V

NTC-COLD

V

BAT

= 4.1V or V

= 4.2V

●

2.455

2.460

2.465

2.475

2.470

V

OVP

BAT

V

Output Low Voltage-STATUS Pin

I = 3mA

●

0.5

0.35

40

0.9

0.6

50

1.2

0.75

65

V

OL-ST

OL-VC

SOFT

O

Output Low Voltage-V Pin

I = 1mA

O

C

I

Status Soft Pull-Down Current

V

= 4.5V

µA

STATUS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C,

A

V_IN= 12V

LTC1729-8.2/LTC1729-8.4

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

DC CHARACTERISTICS

I

V

Supply Current

V

= 9V (Below UVLO)

= 12V, 200µA Pull-Up on V

●

1

6

12

2.0

21

µA

mA

VIN

CC

IN

(9V) No Bat

1.0

10

0.5

1.4

17

3.0

BAT

= 12V, V

= 5V Trickle

= 7V Charge

BAT

●

5.0

V

Undervoltage Lockout High

Undervoltage Lockout Low

9.5

8.5

10.4

9.6

11.4

10.5

V

LKOH

LKOL

VBAT

IN

I

Current

V

= 9V (Below UVLO), V = 8.4V

BAT

●

–1

60

–19

–2.7

–0.1

95

–16

–1.3

1

µA

mA

BAT

IN

= 12V, V

= 8.5V No Bat

= 5V Trickle

= 7V Charge

140

–9.5

–0.5

BAT

●

V

Clamp

No Bat (External 200µA Pull-Up on V )

BAT

8.5

9

9.5

V

CLAMP

MAX

BAT

High V

Threshold

High Going Threshold

Low Going Threshold

●

8.5

9.013

9

9.5

V

BAT

V

Low V

High Going Threshold

Low Going Threshold

●

5.1

4.9

5.4

5.2

5.7

5.5

V

MIN

BAT

I

SENSE Pin Current

Charge State, V

= 7V

●

85

100

±1

115

±2.5

110

µA

mV

µA

V

SENSE

V

SENSE Pin C/10 Offset

NTC Pin Current

Charge State, V = (V

– V

)

SENSE

C10

NTC

C10

BAT

I

V

= 1V

90

100

NTC

V

Thermistor Pin Reset Threshold

Thermistor Pin Hot Hold Threshold

0.160

0.206

0.240

NTC-RESET

NTC-HOT

High Going Threshold

Low Going Threshold

●

0.460

0.380

0.486

0.405

0.510

0.430

V

Thermistor Pin Cold Hold Threshold

OVP Pin Voltage

High Going Threshold

Low Going Threshold

●

2.70

2.10

2.79

2.23

2.90

2.35

V

NTC-COLD

OVP

V

= 8.2V or V

= 8.4V

●

2.455

2.460

2.465

2.475

2.470

V

BAT

V

Output Low Voltage-STATUS Pin

I = 3mA

●

0.5

0.35

40

0.9

0.6

50

1.2

0.75

65

V

OL-ST

OL-VC

SOFT

O

Output Low Voltage-V Pin

I = 1mA

O

C

I

Status Soft Pull-Down Current

V

= 4.5V

µA

STATUS

3

LTC1729 Series

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C. (Note 2)

A

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

AC CHARACTERISTICS

TIMER1

TIMER2

TIMER3

TIMER4

Timer for Trickle-Charge Preconditioning

Timer for Charging

●

0.869

2.61

1

3

1.305

3.55

Hr

Timer for V

Filter

0.764

3.055

6.66

0.859

3.5

1.043

4.17

sec

µs

MAX

C/10

T

Oscillator Period

7.63

9.09

OSC

Note 2: V = 8V for LTC1729-4.1/LTC1729-4.2; V = 12V for

LTC1729-8.2/LTC1729-8.4

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

IN

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PIN FUNCTIONS

OVP (Pin 1): Output from an Internal Precision Resistor

Divider Used as a Voltage Feedback Monitor for Constant-

Voltage Mode Charging.

If the NTC pin is below 0.2V, the state machine is forced

in the reset mode with all the timers cleared to zero. The

current sources on the BAT pin and SENSE pin are

disabled leaving the 55k OVP divider. The STATUS pin is

pulled low in the Reset mode.

BAT (Pin 2): Input to Battery Monitor Circuits and OVP

Resistor Divider. The battery monitor circuits activate

trickle charge preconditioning, battery present detection

andC/10currentdetection. Thispinisinahighimpedance

state when V_CCis below the undervoltage lockout thresh-

old. During trickle charge preconditioning and charging

the BAT pin sources 16mA and 1.3mA respectively. The

current sources are clamped from driving the BAT pin

above 4.5V/cell with an internal pull-down transistor.

There is a 100µA current source on the NTC pin to bias the

NTCthermistor.ThiscurrentsourceisactivewhiletheV_CC

is greater than the undervoltage lockout threshold.

STATUS (Pin 6): Open-Drain Output for C/10 Charge

Termination Detection Circuit. When in the Charge state,

thispinispulledlow. Oncethechargecurrentdropsbelow

the C/10 current threshold for three seconds, the pull-

down transistor is disabled, and a 50µA pull-down current

sink remains activated until the 1- or 3-hour time-out or

the battery or wall adapter is removed.

IntheNoBat, DoneandPausestatesortheHoldandReset

modes, thecurrentsourcesareturnedoff, leavingonlythe

55k OVP divider as a load on the BAT pin. Most chargers

have a 200µA current source that will compensate for this

50µA to 80µA load.

V_C(Pin 7): Open-Drain Output for turning off the charger.

When this pin is open circuit, the charger is active.

Normally this pin allows the charger to be active for three

hours.

SENSE (Pin 3): Input to C/10 Current Detection Circuit.

Thispinsinks100µAduringtheChargestatewhichisused

to program the C/10 current threshold.

V_CC(Pin 8): Input Supply. For 4.1V or 4.2V single cell

operation, V_CCshould be between 8V and 28V with the IC

turning off when V_CCdrops below 6V. For 2-cell applica-

tions, the undervoltage lockout is 10.4V with a minimum

V_CCof 12V. Removing the wall adapter will trigger an

undervoltage lockout and put the part in a high impedance

condition. When the supply is connected, the part is

initialized in the Reset mode with the state machine forced

in the Charge state with all the timers set to zero.

GND (Pin 4): Ground.

NTC (Pin 5): Input to the NTC Thermistor Monitoring

Circuits. When the voltage on this pin is above 2.79V

(cold) or below 0.405V (hot), the state machine is locked

in the present state and the timer is stopped. This is called

the Hold mode. While in the Hold mode, the charger is

turned off via the V_Cpin and the current sources on BAT

and SENSE pins are turned off. The STATUS pin is not

affected.

4

LTC1729 Series

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BLOCK DIAGRA

7

6

V

C

M2

M3

3

SENSE

UVLO

100µA

STATUS

–

COMP1

+

50µA

1.3mA

16mA

C/10

COMP2

COMP3

BAT

OVP

2

1

+

–

V

MAX

4.5V/CELL

CLAMP

UVLO

M1

4.5V/CELL

2.7V/CELL

LOGIC

AND

TIMER

2.465V

+

–

V

MIN

HOLD

100µA

COMP4

COMP5

COMP6

+

–

NTC

5

2.79V

+

–

0.405V

+

–

0.2V

RESET

1729 F02

Figure 2. Block Diagram

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APPLICATIONS INFORMATION

Overview

standard LT1510 application. The LTC1729 provides a

complete and tiny solution for cellular phones and other

portable applications.

The LTC1729 is a charge termination controller for the

LT1505/LT1510/LT1511/LT1512/LT1513/LT1769 con-

stant-voltage/constant-current battery charger family.

Table1detailsthesechargers.Theprimaryfunctionofthis

IC is to stop the charger after three hours of constant-

voltage/constant-current charging. The secondary func-

tion of this controller includes an indication when the

charge current (during constant-voltage mode) drops

below a user-selected threshold. A 500kHz Li-Ion cell

phone charger is shown in Figure 1. The LTC1729 only

needs six external components when combined with the

Table 1. Battery Chargers

LT1505

LT1510

LT1510-5

LT1511

LT1512

LT1513

LT1769

4A Step-Down Charger with Input Current Limit

1.5A Step-Down Charger

1.5A 500kHz Step-Down Charger

3A Step-Down Charger with Input Current Limit

2A Switch SEPIC Charger

3A Switch SEPIC Charger

2A Step-Down Charger with Input Current Limit

5

LTC1729 Series

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APPLICATIONS INFORMATION

Block Diagram

the V_Cpin, reducing the duty cycle of the charger. If the

battery protection circuit quickly returns battery connec-

tion to the charger (in less than one second), then the

LTC1729 continues charging without resetting the timers.

Figure 2 shows the block diagram of the LTC1729. The IC

consists of six comparators, a resistive divider, a UVLO

block and a logic and timer block.

For a battery that has been over-discharged, the LTC1729

provides a 16mA start-up current. This preconditioning

trickle charge begins when the battery voltage drops

below 2.7V/cell. Comparator COMP3 is used to determine

when this condition exists. The battery operating range is

summarized in Figure 4.

The comparator COMP1 is used to indicate C/10 charge

current threshold. (“C” is a term used to indicate the

Ampere-hour capacity of a cell.) Figure 3 details the C/10

detection circuit. The resistor and capacitor on the SENSE

pin filter the signal from the 0.2Ω current sense resistor

R1. The 100µA current sink on the SENSE pin develops

20mV across the 200Ω resistor R2. This sets a 20mV

offset on COMP1 that sense resistor R1 must equal before

C/10currentisindicated.TheC/10isnotrecognizedbythe

logic until it passes through a 3-second digital filter.

With a 10k negative TC thermistor connected to the NTC

pin, the LTC1729 will disable charging if the temperature

is not in the 0°C to 50°C range. A thermistor must be

present at this pin, or if the temperature qualification

featureisnotused,a10kresistormustbeusedinitsplace.

This pin should not be left open. The NTC thermistor

monitoringcircuitsconsistofCOMP4,COMP5andCOMP6.

The NTC pin voltage range is shown in Figure 5.

Forcaseswheretherearemultiplebatteriestobecharged,

theLTC1729detectswhenabatteryisremovedandresets

the timers for the next charge cycle. The battery present

detection is the primary function of comparator COMP2.

When the battery is disconnected from the LTC1729, the

voltage at the BAT pin will begin ramping upward. This is

due to a current source inside the charger or an external

pull-up resistor. Once the voltage on the BAT pin exceeds

the 4.5V/cell limit, COMP2 signals a V_MAX= true to the

logic and turns on a transistor that clamps the voltage.

Comparators COMP4 and COMP5 signal the logic when

the temperature is below 0°C or above 50°C. The 100µA

bias current through the 10kΩ thermistor will generate

2.79V at 0°C and 0.405V at 50°C. The voltage hysteresis

on COMP4 and COMP5 is designed to give 10°C of

temperature hysteresis. If the voltage on the NTC pin

drops below 0.2V, the comparator COMP6 generates a

reset to the logic and timer block.

There is the possibility of an overvoltage transient at the

charging terminals. This occurs if the battery protection

circuit, which is often included in the battery pack, opens

the connection to the battery during high current charging

(constant-currentmode).Thisisaresultofenergystorage

intheinductor.COMP2sensestheovervoltageandclamps

To provide accurate charge voltages, the internal resistor

divider is trimmed to provide a precise ±0.2% voltage of

2.465V at the OVP pin for the four battery voltage options

of 4.1V, 4.2V, 8.2V and 8.4V.

V

CC

CHARGING

CURRENT

LTC1729

CHARGE

LED

I

BIAS

100µA

20mV

STATUS

SENSE

BAT

–

+

–

+

LOGIC

AND

TIMERS

R2

200Ω

C1

1µF

R1

0.2Ω

3-SEC

FILTER

20mV

COMP1

+

50µA

–

1729 F03

Figure 3. C/10 Detection Circuit

6

LTC1729 Series

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APPLICATIONS INFORMATION

V

= 1V

= 0V

BATTERY CLAMP

PULL-DOWN

ON

MAX

MIN

CHARGE

RESET MODE

4.5V/CELL

I

= 0

BAT

STATUS = PULL-DOWN

V

MAX

V

MIN

= 0V

NORMAL CHARGE

V

= PULL-DOWN

C

V

< V

MIN

V > V

BAT MIN

2.7V/CELL

BAT

NOTE: FOR STATUS

PULL-DOWN = HARD:

FOR CURRENT > C/10

PULL-DOWN = 50µA:

V

MAX

V

MIN

= 0V

= 1V

TRICKLE CHARGE

PRECONDITIONING

PRECONDITION

= 16mA

V

> V

< V

CHARGER “ON”

= 1.3mA

BAT

MIN

I

BAT

STATUS = PULL-DOWN

= PULL-DOWN

BAT

STATUS = PULL-DOWN

= OPEN

1729 F04

FOR CURRENT < C/10 FOR 3SEC

BAT

MIN

V

C

t

= 1HR

t

= 3HR

MAX

Figure 4. BAT Voltage Operating Range

V

< V

MAX

BAT

FOR MORE THAN 1SEC

TIME > t

V

BAT

> V

MAX

= 0

PAUSE

= 0

DONE

BAT

V

< V

BAT

MAX

I

BAT

STATUS = PULL-DOWN

= PULL-DOWN

FOR MORE THAN 1SEC

STATUS = OPEN

V

= PULL-DOWN

C

V

> V

MAX

V

> V

MAX

BAT

FOR MORE THAN 1SEC

HOLD MODE

FOR MORE THAN 1SEC

NO BAT

I

= 0

BAT

STATUS = OPEN

= PULL-DOWN

2.79V

V

C

NORMAL CHARGE

0.405V

V

> 2.79V OR

< 0.405V

V

NTC

V

NTC

< 2.79V AND

> 0.405V

NTC

HOLD MODE

= 0

0.2V

I

BAT

STATUS = PREVIOUS STATUS

= PULL-DOWN

RESET MODE

1729 F05

V

C

1729 F06

Figure 6. State Diagram

Figure 5. NTC Voltage Operating Range

When the input supply is removed in step-down charger

designs, the V_CCpin does not drop to 0V, but is held to a

diode drop below the battery voltage. This is due to the

internal parasitic diode from the SW pin to the V_CCpin that

is present in the LT1510, LT1511, LT1769, and the body

diodeofthetopMOSFETintheLT1505charger.Removing

the input supply will result in the V_CCpin dropping below

the UVLO threshold, thus shutting down the LTC1729 and

minimizing battery drain. Once the input supply is con-

nected, the LTC1729 resets the timers and begins another

charge cycle. There is a disconnect transistor that will

remove the OVP resistor divider from the battery when the

V_CCvoltage drops below the UVLO threshold.

The logic and timer block consists of a state machine,

oscillator and counter. The state machine will be dis-

cussed in detail in the next section. The oscillator is

internallytrimmedto131kHz. Thecounteriscomposedof

a chain of 25 flip-flops that includes self-test circuitry.

State Machine

The state machine is responsible for the following items:

1. When to start and stop the charger. The internal timer

must be initialized every time a new battery is installed

or when the input supply is applied.

2. When a battery is installed, the state machine must

determine if it is a new battery or if the previous battery

has been reinstalled.

7

LTC1729 Series

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APPLICATIONS INFORMATION

3. When a heavily discharged battery is installed, trickle

charge conditioning must take place before the full

charge current.

requirement for this transition is for the BAT pin voltage to

exceed V_MAXfor more than one second. The IC now

assumes that the battery has been removed.

The state machine diagram is shown in Figure 6. Note that

the Charge state includes the Precondition state, the

charger “ON” state and the Reset mode.

FromtheNoBatstate,thereisonlyonepossibletransition.

TheNoBatstatecanmovetotheChargestateifthevoltage

ontheBATpinremainslessthanV_MAXforonesecond.The

LTC1729 will now work on the assumption that a new

battery has been installed.

Reset and Hold are the two modes that will cause the

chargertostopcharging(V_Cpinpulledlow)andignorethe

state machine. The Reset mode clears all the timers and

forces the state machine to begin in the Charge state

(STATUS pin pulled low). This mode is only activated

momentarilyatpower-uporwhentheNTCpinisbelowthe

Reset threshold. The other interrupt condition is called the

Hold mode. When the voltage on the NTC pin is above

2.79V (cold) or below 0.405V (hot), the state machine is

lockedinthepresentstateuntiltheNTCpinvoltagereturns

to the proper range. While in the Hold mode, the charging

is disabled and the timers are frozen.

Although the Precondition and Charger “ON” both reside

in the Charge state, there are differences between these

states. The main purpose of the Precondition state is to

slowlybringaheavilydischargedbatteryuptoaminimum

level before full charge current begins. The Precondition

state uses a 16mA current source to trickle charge the

battery with a 1-hour time-out transition to the Done state.

The Charger “ON” state enables the external charger and

the time-out is increased to three hours. For the entire

time in the Precondition state, the STATUS pin uses a hard

pull-down. In the Charger “ON” state the STATUS pin uses

two types of pull-down: hard pull-down and soft 50µA

pull-down.

The charger is enabled only during the charger “ON” state.

There are three ways that the state machine can exit the

charger“ON”state. Thefirstisfora3-hourtime-outwhich

is denoted as the time > t_MAXtransition to the Done state.

Second, if the battery is removed from the charger, the

V_MAXsignal is activated as mentioned in the Block Dia-

gram section. This causes the state machine to make the

V_BAT> V_MAXtransition to the Pause state. The third way to

exit the charger “ON” state is with a V_BAT< V_MINtransition

to the Precondition state. The battery will need to drop

below 2.6V/cell to be less than V_MIN. This is not a likely

scenario.

The STATUS pin is designed to provide an indication that

the battery is charging. Once the current drops below the

C/10 threshold, the battery is close to being fully charged.

The LTC1729 turns off the hard pull-down once the

C/10 comparator is active for more than three seconds.

The 50µA soft pull down remains in effect until the 3-hour

time-out is completed or the input power is removed.

Terminate at C/10 Current

Charging can also be terminated using C/10 detection

rather than the 3-hour time-out. By connecting the low

side of the NTC thermistor to the STATUS pin instead of

ground, the NTC pin will float to 5V as soon as the Status

pull-down is open. This will force the state machine into

the Hold mode. The V_Cpin is pulled low which turns off the

charger. This circuit is shown in Figure 7.

Once in the Pause state, there are two ways to proceed.

The first is to go to the No Bat state. This requires that the

V_BATremain greater than V_MAXfor more than one

second. From these conditions, the LTC1729 interprets

that a battery has been removed. If the voltage on the BAT

pin stays less than V_MAXfor more than one second, then

the state machine returns to the Charge state (Precondi-

tionandcharger“ON”).Thisisinterpretedasamomentary

open caused by the battery pack protection circuitry or

loose contact.

In order to restart the charging process for a new battery,

the NTC pin will need to be momentarily brought below

0.2V or the V_CCpin brought below the UVLO threshold.

The automatic battery detection features are disabled

during the Hold mode.

The Done state can only proceed to the No Bat state. From

outside the LTC1729 this transition is undetectable. The

8

LTC1729 Series

U

W U U

APPLICATIONS INFORMATION

LTC1729-4.2

open-drain STATUS pin turns off. Connecting an LED to

the STATUS pin will give a visual indication during the

precondition trickle charge and the portion of the main

charge before C/10 has occurred.

1

2

3

4

8

7

6

5

V

CC

OVP

BAT

OVP

BAT

V

CC

0.1µF

V

C

1µF

200Ω

SENSE

SENSE STATUS

GND NTC

By reducing the LTC1729 SENSE pin resistor to 0Ω, the

STATUS pin function can be changed to a charging indica-

tor (Figure 8). The LED on the STATUS pin will always go

off after the 3-hour charge cycle is completed, regardless

of the C/10 circuitry.

10k NTC THERMISTOR

NTHS1206N02 VISHAY/DALE

1729 F07

Figure 7. Terminate Charging at C/10

Using Status as a Charging Indicator

CHARGE

CURRENT

LTC1729

In many applications circuits shown in this data sheet, the

STATUS pin is used to indicate when C/10 has occurred

(charge current has dropped to 10% of the full charge

current). This C/10 number is not fixed, but is set by an

external resistor connected to the LTC1729 SENSE pin. A

100µA bias current through this resistor develops a volt-

age which is compared with the voltage across the charge

current sense resistor. When these voltages are equal, the

I

BIAS

100µA

SENSE

BAT

–

+

–

SENSE

RESISTOR

COMP1

+

1729 F08

Figure 8. Modify C/10 Indication to Create Charging Indicator

U

TYPICAL APPLICATIONS

SEPIC Charger with 0.5A Output Current

L1A**

INPUT POWER

4V TO 9V

C2*

2.2µF

D1

+

R6

0.2Ω

BOOST

V

OSC

LV

MBRS130LT3

D2

C3

22µF

+

V

IN

CAP

V

SW

1/2 BAT85S

+

LTC1044

C1

22µF

4.2V

GND

+

L1B**

C8

10µF

R1

29.4k

S/S

LT1512

–

CAP

V

OUT

V

I

FB

R4, 24Ω

R2

12.4k

GND

FOR 3.5V TO 14V USE LTC1144

V

C

R3

0.2Ω

C4

0.22µF

C5

0.1µF

R5

1k

D3

1/2 BAT85S

R

PULLUP

10k

1729 F11

C7

10µF

R9

1k

OVP

BAT

V

CC

* TOKIN CERAMIC 1E225ZY5U-C203-F

** L1A, L1B ARE TWO 33µH WINDINGS ON A

SINGLE INDUCTOR; COILTRONICS CTX33-3

R7

100Ω

V

†

C

C6

1µF

D4

LTC1729-4.2

SENSE STATUS

†

LUMEX SML-LX0805GW-TR SIZE R9 FOR

20mA TYPICAL

GND

NTC

R8

10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE

NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT

OPTION: TIE R8 TO STATUS FOR

CHARGE TERMINATION AT

LOW CHARGING CURRENT

9

LTC1729 Series

U

TYPICAL APPLICATIONS

4A, 2-Cell Lithium-Ion Battery Charger

TO

SYSTEM

POWER

DBODY

R

M3

S4

C4

0.1µF

V

0.025Ω

IN

Si4435

D3

(FROM

MMSD4148

C

*

IN

ADAPTER)

47µF

R7

500Ω

C1

1µF

C3

V

BOOSTC

BOOST

CC

35V

D2

C2

2.2µF

GBIAS

MMSD4148

0.68µF

M1

R

CLN

CLP

S1

TGATE

SW

Si4412

0.025Ω

5Ω

R5

3k

C

22µF

× 2

***

L1**

15µH

OUT

M2

Si4412

INFET

UV

D4

MBRS140

BGATE

LT1505

+

V

C

SYNC

SHDN

FLAG

CAP

8.4V

R4

3k

C5

R6

PROG

5.1k

R

4.93k

1%

PROG

3 CELL

0.33µF

V

FB

4.2V

4.1V

COMP1

R

S3

S2

R3

R1

1k

C7

200Ω

300Ω

1%

AGND

PGND

C

1µF

C6

0.1µF

PROG

0.68µF

BAT2 BAT SENSE SPIN

R

PULL-UP

10k

OVP

BAT

V

CC

R9

C9

0.1µF

1.4k

V

C

†

C8

0.1µF

D5

LTC1729-8.4

SENSE STATUS

R8

100Ω

10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE

NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT

GND

NTC

* SANYO OS-CON

** SUMIDA CDRH127-150

OPTION: TIE RESISTOR TO STATUS FOR

CHARGE TERMINATION AT

LOW CHARGING CURRENT

*** AVX TPSD226L025R0200

†

LUMEX SML-LX0805GW-TR

1729 F09

10

LTC1729 Series

U

PACKAGE DESCRIPTION ^{Dimensions in inches (millimeters) unless otherwise noted.}

MS8 Package

8-Lead Plastic MSOP

(LTC DWG # 05-08-1660)

0.118 ± 0.004*

(3.00 ± 0.102)

8

7

6

5

0.040 ± 0.006

(1.02 ± 0.15)

0.034 ± 0.004

(0.86 ± 0.102)

0.007

(0.18)

0° – 6° TYP

0.118 ± 0.004**

(3.00 ± 0.102)

SEATING

PLANE

0.193 ± 0.006

(4.90 ± 0.15)

0.012

(0.30)

REF

0.021 ± 0.006

(0.53 ± 0.015)

0.006 ± 0.004

(0.15 ± 0.102)

0.0256

(0.65)

BSC

MSOP (MS8) 1098

1

2

3

4

* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,

PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.189 – 0.197*

(4.801 – 5.004)

7

5

8

6

0.150 – 0.157**

(3.810 – 3.988)

0.228 – 0.244

(5.791 – 6.197)

1

3

4

2

0.010 – 0.020

(0.254 – 0.508)

× 45°

0.053 – 0.069

(1.346 – 1.752)

0.004 – 0.010

(0.101 – 0.254)

0.008 – 0.010

(0.203 – 0.254)

0°– 8° TYP

0.016 – 0.050

(0.406 – 1.270)

0.050

(1.270)

BSC

0.014 – 0.019

(0.355 – 0.483)

TYP

*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH

SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD

FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

SO8 1298

11

LTC1729 Series

TYPICAL APPLICATION

U

3A (LT1511) Or 2A (LT1769), 2-Cell Lithium-Ion Battery Charger

D1

SS24

R1

510Ω

INPUT POWER

11.5V TO 28V

GND

SW

CLP

CLN

R

S4

0.05Ω

TO MAIN

SYSTEM

POWER

V

D4

SS24

CC

C2

0.47µF

+

C1*

15µF

R5

3k

LT1511 OR LT1769

D2

SS24

BOOST

L1**

22µH

D3

MBR0540T

UV

R6

COMP1

5.1K

C3

200pF

PROG

V

SPIN

C

C4

C

PROG

0.33µF

OVP

SENSE

1µF

R3

300Ω

R

BAT

PROG

R2

1k

4.93k

R

S3

S2

200Ω

R

200Ω

S1

1%

0.05Ω

1%

+

C7***

22µF

8.4V

C6

0.1µF

R7

1.4k

OVP

BAT

V

CC

†

V

C

R4

100Ω

D5

C5

1µF

LTC1729-8.4

SENSE STATUS

GND

NTC

10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE

NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT

* TOKIN C55Y5U1E156Z

** SUMIDA CDRH125-220MC

*** AVX TPSD226K025R0200

OPTION: TIE RESISTOR TO STATUS FOR

CHARGE TERMINATION AT

LOW CHARGING CURRENT

†

LUMEX SML-LX0805GW-TR

1729 F10

D1, D2, D4: GENERAL SEMICONDUCTOR

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LT1505

High Efficiency Constant-Voltage/Constant-Current Battery Charger

Constant-Voltage/Constant-Current Battery charger

Uses External Synchronous N-Channel FETs

Up to 1.5A Charge Current for Lithium-Ion, NiCd and

NiMH Batteries, Internal R

LT1510

SENSE

LT1511

LT1512

LT1513

LTC1759

LT1769

3A Constant-Voltage/Constant-Current Battery Charger

SEPIC Battery Charger

Charges Lithium, NiCd and NiMH Batteries

V

Can Be Higher or Lower Than Battery Voltage, 2A Switch

Can Be Higher or Lower Than Battery Voltage, 3A Switch

IN

SEPIC Battery Charger

SMBus-Controlled Smart Battery Charger

2A Constant-Voltage/Constant-Current Battery Charger

LT1505 Charger Functionality with SMBus Control

In 28-Pin SSOP Package

1729i LT/TP 1099 4K • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

12

●

(408)432-1900 FAX:(408)434-0507 www.linear-tech.com

LINEAR TECHNOLOGY CORPORATION 1999


型号：	LTC1729CS8-8.2#TRPBF
厂家：	Linear
描述：	LTC1729 - Li-Ion Battery Charger Termination Controllers; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C 电源电路电池电源管理电路光电二极管控制器
文件：	总12页 (文件大小：203K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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