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HOUSEKEEPING CIRCUIT :
Over voltage protection for 3.3V, 5V and 12V
without external components
Additional Over voltage protection (-5V and/
or -12V, or Primary Over Power control) with
external components
Under voltage protection for 3.3V, 5V and
12V without external components
Over current protection for 3.3V, 5V and 12V
with internal threshold voltage
Externally adjustable Inrush Current blanking
during transients
Externally adjustable Under voltage blanking
during Power Up
Power Good output
Externally adjustable PG delay
Remote input
Externally adjustable Remote delay
Internal Precision Voltage Reference (Vref1)
PWM GENERATOR :
Error Amplifier (easy compensation)
Oscillator (adjustable frequency)
PWM generation
Soft Start & Dead Time Control (adjustable)
Open collector outputs for indirect Pulse
Transformer driving
Precision Voltage Reference (Vref2) (Uncom-
mitted with Vref1)
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DESCRIPTION
The TSM121 integrated circuit incorporates all
sensing circuit to regulate and protect from over
voltage, under voltage and over current a multiple
output power supply (12V, 5V, 3.3V).
TSM121 incorporates all the necessary functions
for proper PWM generation and pulse transformer
drive to be adapted easily in the PC SMPS power
supplies, and all the Housekeeping features which
allow safe operation in all conditions, and very
high integration.
TSM121 integrates two independent Voltage Ref-
erences which are uncommitted to ensure safe
Regulation and Protection by the same chip.
APPLICATION
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Primary PWM and secondary housekeeping
in PC/Server SMPS using Half Bridge topol-
ogy
ORDER CODE
N =
Dual in Line Package (DIP)
PIN CONNECTIONS
(top view)
Part
Number
Temperature
Range
Package
Marking
N
TSM121C
0 to 85°C
TSM121C
N
DIP24 shrink
(Plastic Package)
VCC
FB
IN-
IN+
OSC
REM
TREM
TPG
PG
IS12
VS33
VS5
VS12
PI
TUV
EP
TSUR
GND
VREF2
SS/DTC
10
9
8
7
6
5
4
3
2
1
11
12
13
14
15
16
17
18
19
20
21
22
23
24
C2
C1
IS5
IS33
TSM121
SINGLE CHIP PWM & HOUSEKEEPING IC
FOR HALF BRIDGE SMPS
January 2001