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Circuit Operating Descriptions
Vswitch
dt
0
Toff
(c) PQIZ1 Vcc circuit
1) PQIZ1 Vcc : PVRL4, PVDL1, PVCL1
! Use the output of transformer as Vcc,because the current starts to flow into transformer while PQIZ1 is
active
@ Rectify to PVDL1 and smooth to PVCL1.
# Use the output of transformer as PQIZ1 Vcc : The loads are different before and after PQIZ1 driving.
(Vcc of PQIZ1 decreases below OFF voltage , using only the resistance dut to lode increase after PQIZ1
driving.)
(d) Feedback Control Circuit
ICE3B2065P
13-2
Inverted power
by leakage
inductance
Fig. 13-2
TRANS(PQTZ1)
PBIZ1
PFID1
(b) SNUBBER Circuit :
PSRZ1, PSRZ2, PSCX1, PSCZ2, PSDZ1
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 PQIZ1 because dt is a very short.
2) SNUBBER circuit protects PQIZ1 from damage
t
through leakage voltage suppression by RC,
(Charges the leakage voltage to PSDZ1 and PSCX1
and discharges to PSRZ1, PSRZ2).
3) PSCZ2 : For noise removal
PPDF1
PPLF1
PPC1
PPCF3
PFRF1
PFRF2
PFRF3
Fig. 13-3
5.8V
PFRF4
PFRF5
PFCF1
PFRF6
Samsung Electronics
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