Daewoo DTH-14Q1FS Service Manual page 20

E. POWER BLOCK
This chassis designed for free voltage(AC 100V ~ AC 220V ) power. power block contains power IC, SMPS
transformer and several passive components.
The power IC STR-S5707 has power transistor. oscillator circuit, voltage comparator circuit, thermal protection
circuit, OCP(over current protection) circuit insiude.
1.STR-S5707 BLOCK DIAGRAM
7
SENS
PNP +2Di
R6
R7 R8 R9
2.PIN DESCRIPTION
PIN NO SYMBOL
1 C COLLECTOR
2 GND GROUND
3 B BASE
4 SINK SINK
5 OCP OVER CURRENT PROTECTION
6 INH INHIBIT / LATCH
7 F/B(SENS) FEED BACK(SENSING) INPUT
8 DRIVE DRIVE
9 Vin Vin
3. OTHER FUNCTION
Symbol Function
OVP Built-in Overvoltage Protection Circuit
TSD Built-in Thermal Shutdown Circuit
V IN
9
START UP OVP
PRE REG
T.S.D
R1
C1
NAME
LATCH
PROPOTIONAL
DRIVE
OSC
OCP
INH-1
REF
INH-2
REF
INH-3
REF
R2 C2 C4 R5
6
INH
POWER TRANSISTOR COLLECTOR
GROUND(POWER TRANSISTOR EMITTER)
POWER TRANSISTOR BASE
BASE CURRENT (Is) INPUT
OVERCURRENT SENSING SIGNAL INPUT
SYNC, OFF TIME/LATCH CIRCUIT CONTROL INPUT
CONSTANT VOLTAGE CONTROL SIGNAL INPUT
BASE DRIVE CURRENT (Id) OUTPUT
SUPPLY VOLTAGR FOR CONTROL CIRCUIT
18
Tr2
8
R3
4
R4
3
REF
1
Tr1
2
R4
5
C3
FUNCTION
DIRVE
SINK
B
C
GND
OCP