4-3
DVW-250/250P
Power Supply System
A voltage of 12 Vdc sent from the battery or DC IN
connector is passed through the power selection circuit and
breaker on the FU-63 board and sent to the DC/DC
converter (on the PSW-31 board).
The DC/DC converter converts 12 Vdc into various DC
voltages and sends them to each block of this unit and the
external camera.
The major features of the DC/DC converter are as follows:
• A high-efficiency PWM switching regulator system is
used as the converter system.
• An overcurrent protection circuit that cuts off the output
of the voltage when an output pin was short-circuited is
provided.
• A circuit that cuts off the output voltage when an input
voltage became less than the guaranteed operating
voltage is provided.
• Power is partially supplied to the SST-3 and CP-260
boards even if the power switch is turned off. This
enables the remaining battery amount and alarm to be
displayed with the power turned off.
The SST-3 board mounts an internal lithium battery, stores
the RAM data, and drives the time code reader and genera-
tor (SST-3 board).