Sony DSC-D700 Service Manual page 108

2. Channel control function
This circuit can independently control a 4-channel power circuit. This time, the
output signal of this circuit can be obtained when the voltage level is high with
pins 20, 21, and 22 connected.
3. Protection functions
1) Timer latch-type short protection circuit
An SCP comparator detects each comparator output voltage level for output
short-circuit detection. When at least one output voltage becomes more than
2.1 V, the timer circuit operates and the external capacitor at the SCP pin (pin
23) begins charging. A latch circuit operates when the output voltage
described above is not restored to the normal voltage until this voltage rises
to the Vbe voltage. After that, an output transistor is turned off, and
simultaneously, the pause period is set to 100 %. The power can be turned
on again for restoration when this protection circuit operates.
2) Malfunction prevention circuit during low-voltage input
The transient state during the power-on sequence or the instantaneous
decrease in a supply voltage causes the malfunction of a control circuit, and
damages or deteriorates the system. This function turns off an output
transistor to prevent a malfunction by detecting the supply voltage level and
resetting a latch circuit.
4. Transformer T651 outputs _7.5 V of a system control block and 15 V of LCD in
the winding ratio of a transformer because a circuit consists of parts on the RM-
177 board.
5. Transistor Q654 controls and drives the power. It covers more than the output
current of each power.
6. An UNREG2 voltage is sent from connector CN652 to the RM-177 board. The
voltage produced on the RM-177 board is sent from each pin of connector
CN652 to the unit through the PS-536 board.
7. As described in the attached paper, connector CN651 mounts the parts that sense
the infrared command signal sent to the KC-47 board. In other words, the power
is supplied from pin 4 of IC651 and an infrared command is output from pin 1.
Pins 5 and 6 of connector CN652 corresponds to the WB hold switch.
8. A signal that drives the self-timer LED mounted on the RM-177 board is input to
pin 4 of connector CN652.
9. Pins 7 to 15 of connector CN651 are used as the interface for sending the control
signal of a stroboscopic unit from the KC-47 board to the camera board through
CN653.
4-20 DSC-D700 (UC,CE)