AN1051 Datasheet, PDF (1/9 Pages) STMicroelectronics – This application note explains how to use the VIPER20

AN1051
®
APPLICATION NOTE
TSM102 : A DUAL LI-ION BATTERY CHARGER
USING AN ST SILICON TRIPLET
by A. BAILLY, D. CABROL, J. CAMIOLO
S. LAFFONT, R. LIOU
.....^{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.
Figure 1 : ST62T25C, TSM102A and VIPER20 Pin
Vdd
TIMER
OSCin
OSCout
NMI
PC7
PC6
PC5
PC4
TEST
!RESET
PB7
PB6
PB5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DIP28 - SO28
28 Vss
27 PA0
26 PA1
25 PA2
24 PA3
23 PA4
22 PA5
21 PA6
20 PA7
19 PB0
18 PB1
17 PB2
16 PB3
15 PB4
1
2
3
V _CC+
5
6
7
Vref
TSM102
COMP
COMP
16
15
14
V _CC-
12
11
10
PowerSO-10
DRAIN
OSC 6
Vdd 7 _VIPER20
NC 8
NC 9
COMP 10
5 SOURCE
4 SOURCE
3 NC
2 SOURCE
1 SOURCE
Cathode
Pentawatt-HV
VIPER20
February 1999
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