5

LTC1729 Series

BLOCK DIAGRA

BAT

3

2

OVP

1

NTC 5

SENSE

STATUS

100

µA

1729 F02

6

7

COMP1

–

+

COMP4

UVLO

2.465V

2.79V

100

µA

1.3mA

16mA

4.5V/CELL

CLAMP

–

+

COMP2

4.5V/CELL

–

+

COMP3

C/10

HOLD

RESET

2.7V/CELL

–

+

COMP5

0.405V

–

+

COMP6

0.2V

LOGIC

AND

TIMER

UVLO

M1

M2

M3

50

µA

Figure 2. Block Diagram

Overview

The LTC1729 is a charge termination controller for the

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

stant-voltage/constant-current battery charger family.

Table 1 details these chargers. The primary function of this

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

standard LT1510 application. The LTC1729 provides a

complete and tiny solution for cellular phones and other

portable applications.

Table 1. Battery Chargers

LT1505

4A Step-Down Charger with Input Current Limit

LT1510

1.5A Step-Down Charger

LT1510-5

1.5A 500kHz Step-Down Charger

LT1511

3A Step-Down Charger with Input Current Limit

LT1512

2A Switch SEPIC Charger

LT1513

3A Switch SEPIC Charger

LT1769

2A Step-Down Charger with Input Current Limit