Panasonic KX-FL513RU Service Manual page 188

KX-FL513RU
7.14.2. CHG-BIAS (Charge BIAS)/DEV(-) BIAS (Developing(-) BIAS)/DEV(+) BIAS
(Developing(+) BIAS) UNIT
When the CHG REM terminal becomes "L", the transistor Q201 turns ON by IC101, Charge BIAS(-1000V) is output from CHG
OUTPUT, Developing(-) BIAS(-200V) is output from DEV(-) BIAS. After that, when DEV CHG terminal becomes "L", Q202 turns
ON, and Developing(+) BIAS(+150V) is output from DEV(+) BIAS.
7.14.3. TRA(+) BIAS (Transfer(+) BIAS)/TRA(-) BIAS (Transfer(-) BIAS) UNIT
When the CHG REM terminal is "L" and the TRA CLK terminal is "Open", Transfer(-) BIAS(-1000V) is output from TRA OUTPUT
the moment Charge BIAS(-1000V) is output from CHG OUTPUT. When 7.8KHz PWM (pulse-width modulation) signal is input to
the TRA CLK terminal, Q103 turns ON by IC101, and TRA(+) CURRENT BIAS according to the PWM signal is output from TRA
OUTPUT. The PWM signal will be turned to a constant voltage by the resistor and the condenser, and input to the IC101. The
IC101 compares this voltage with the feedback voltage from T101 and controls the Q103. As for the transfer current, +25µA is
output when DUTY of the TRA CLK input signal is 0%, or +4µA is output when that is 72%.
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