Samsung BD-P1000 Service Manual page 122

Circuit Operating Descriptions
Vswitch
dt
0
Toff
(c) Vcc circuit
1) R11, R12 : IC01 driving resistance (IC01 works through driving resistance at power cord in)
2) IC01 VCC: R13, D11, C11, ZD10,
IC02 VCC: D12, R16, C20, ZD11
! Use the output of transformer as Vcc,because the current starts to flow into transformer while IC01, IC02 is
active
@ Rectify to D11, D12 and smooth to C11, C20.
# Use the output of transformer as IC01, IC02 Vcc : The loads are different before and after IC01, IC02 driving.
(Vcc of IC01, IC02 decreases below OFF voltage , using only the resistance dut to lode increase after IC01,
IC02 driving.)
(d) Feedback Control Circuit
IC01(ICE3B5065P)
13-2
Inverted power
by leakage
inductance
Fig. 13-2
TRANS PT01
IC05
IC07
1) Prevent residual high voltage at the terminals of
switch during switch off/Suppress noise.
High inverted power occurs at switch off,
because of the 1st winding of transformer :
(V=-L1 xdi/dt. L1 : Leakage Induction)
A very high residual voltage exist on both terminals
of IC01,IC02 - PIN 1 because dt is a very short.
2) SNUBBER circuit protects IC01,IC02 from damage
through leakage voltage suppression by RC,
(Charges the leakage voltage to D10,C12,C13
t
and discharges to R11,R12).
PT02 : Chrages the leakage voltage to D15,c18,c19 and
dischages to R20,R21
D32
L30, L33
C36, C42
C35
D39
R32
R33
R34
Fig. 13-3
5.8V
R47
R35
C39
R36
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