3-30
CIRCUIT DESCRIPTION
Samsung Electronics
Repair Manual
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 ter-
minal 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 resis-
tance Q402 via R408 and C403 and Q402 turns on. When the current is accepted to Q402, Ic increases to the current pro-
portional 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 sec-
ondary unit, sends current to the load and outputs MHV voltage through the high voltage output enable, which is com-
prised of Regulation– circuit.
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-invert-
ing 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 cur-
rent 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.
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