Samsung SCX-5315F Service Manual page 152

Circuit Description
3-5-7-4 MHV (Electrification Output Enable)
Electrification Output Enable is the electrification output control signal 'PWM-LOW ACTIVE'.
When MHV-PWM LOW signal is received, Q401 turns on and the steady voltage will be accepted to the non-
inverting terminal of OP-AMP 324. As the voltage higher than the inverting reference voltage of OP-AMP,
which is set to R405 and R406, OP-AMP output turns high. This output sends IB to the TRANS auxiliary
wire through current-restricting resistance Q402 via R408 and C403 and Q402 turns on. When the current
is accepted to Q402, Ic increases to the current proportional to time through the T401 primary coil, and when
it reaches the Hfe limit of Q402, it will not retain the "on" state, but will turn to "off". As Q402 turns 'off',
TRANS N1 will have counter-electromotive force, discharge energy to the secondary unit, sends current to
the load and outputs MHV voltage through the high voltage output enable, which is comprised of Regula-
tion– circuit.
U103 7407
MHV-PWM
R412 2.2K
3-5-7-5 BIAS (supply/dev/blade output unit)
BIAS (Electrification Output Enable)Electrification Output Enable is the electrification output control signal
'PWM-LOW ACTIVE'.When BIAS-PWM LOW signal is received, Q501 turns on and the steady voltage will
be accepted to the non-inverting terminal of OP-AMP 324. As the voltage higher than the inverting reference
voltage of OP-AMP, which is set to R506 and R507, OP-AMP output turns high. This output sends IB to
the TRANS auxiliary wire through current-restricting resistance Q502 via R509 and C504 and Q502 turns
on. When the current is accepted to Q502, Ic increases to the current proportional to time through the T201
primary coil, and when it reaches the Hfe limit of Q502, it will not retain the "on" state, but will turn to "off".
As Q502 turns 'off', TRANS N1 will have counter-electromotive force, discharge energy to the secondary
unit, sends current to the load and outputs DEV voltage through the high voltage output enable, which is
comprised of Regulation-circuit.
5V
R520
R501
26K
Q501
100
BIAS-PWM
A708-Y
2
CON03-#24
U103-A
R519
7407
2.2K
R503
100KF
R502
2K
3-32
18V
R405 220K
Q401 A708
R403 130K
R404
27K
R402
82K
C407
R411 2K
104
R406
2.2K
C503
R508
104
47K
R506
86.6KF
5
_
7
U1
+
6
U101-B
C501
R504
KA324
104
56.6KF
C502
R507
222
12KF
- This Document can not be used without Samsung's authorization -
24VS
Q402
D526
24VS
R408 R409
+
47K 390
_ KA324
C403
333
24VS
D502
T201
4KV
KAB-007
7
1
5 6
Q502
D526-Y
C505
2
2KV 680
4
R509 R510
47K 430
C504
R511
333
1W 3
T401
C404
3K/471
C406
D402
4KV 3K/471
R416
15M
R417
15M
R514
MGR1/2W 50K
ZD501
C506
R515
100V
3KV 471
MGR1/2W 50K
ZD501
100V
R512
MGR1/2W 12MF
R516
MGR1/2W 50K
Samsung Electronics
MHV OUTPUT
R413
12M
OPC
ZD401
150V
BLADE
SUPPLY
DEV