AN1051

APPLICATION NOTE

TSM102 : A DUAL LI-ION BATTERY CHARGER

USING AN ST SILICON TRIPLET

February 1999

by A. BAILLY, D. CABROL, J. CAMIOLO

S. LAFFONT, R. LIOU

®

Figure 1 : ST62T25C, TSM102A and VIPER20 Pin

This application note explains how to use the VIPER20, the ST62

µController and the TSM102A in an

SMPS-type battery charger which features :

.

Dual Li-Ion Battery charging with Constant Current/Constant Voltage

.

Battery type recognition (4.1V or 4.2V and different capacities)

.

Precision Voltage Control

.

Temperature and Failing Battery protection

.

End of Charge detection

1 - DEVICES PRESENTATION

The VIPER20 integrates on the same chip a PWM circuit together with a high voltage avalanche rugged

vertical MOSFET (600V, 0.5A) which make it ideal for primary side control of battery chargers or power

supplies featuring up to 20W output. Moreover, this device allows stand-by mode operation without

additional components.

The ST62T25C is a low cost 28 pins 8-bit Microcontroller available in Mask ROM, FastROM and OTP

versions. It features an A/D converter with up to 16 channels, 20 I/O pins of which 4 have High Current

capability. An integrated Static Reset circuitry, Oscillator Safe Guard, 3 to 6 V power supply range and high

ESD tolerance make the device well suited for noisy environment.

The TSM102A integrated circuit includes two Operational Amplifiers (type LM358), two Comparators (type

LM393) and one adjustable precision Voltage Reference (type TL1431 : 2.5V to 36V, 0.4% or 1%). TSM102A

can sustain up to 36V power supply voltage.

1

2

3

14

15

16

5

6

7

12

11

10

V

Vref

Cathode

V

COMP

COMP

TSM102

1

2

3

5

6

7

12

DIP28 - SO28

4

8

9

10

11

13

14

28

27

26

24

23

22

17

25

21

20

19

18

16

15

Vdd

TIMER

OSCin

NMI

PC7

PC6

PC5

PC4

TEST

!RESET

PB7

PB6

PB5

OSCout

Vss

PA0

PA1

PA2

PA3

PA4

PA5

PA6

PA7

PB0

PB1

PB2

PB3

PB4

1

2

3

5

4

10

9

8

6

7

VIPER20

PowerSO-10

OSC

Vdd

NC

NC

COMP

SOURCE

SOURCE

SOURCE

SOURCE

NC

DRAIN

Pentawatt-HV

VIPER20

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