However, a part of low-voltage power supply circuit is mounted on the VPR-124 board, DCP-64, and DPR-355 boards.
Input power supply (UNREG) system operations
An UNREG power voltage is input and is changed to the EVER power voltage state. The power switch ON/OFF state
can be recognized in this mode.
When the power microcomputer (RE-320 board: IC202) recognizes the power switch ON state, the power
microcomputer controls power of each block according to instructions of the system controller (DPR-355 board:
IC2100).
The ordinary input power (UNREG) value is approx. +11 V to +17 V.
• Battery/EXT-DC inputs
There are two types of power input: battery and EXT-DC. If battery power and EXT-DC power are input
simultaneously, the EXT DC power input takes precedence.
• Protection of input overvoltage
When a high UNREG power voltage is supplied, the overvoltage protection circuit is activated at the set value of
+19.5 V and the camera body is shut down. This circuit automatically resumes power when the input power voltage
lowers to +19.5 V or less.
• Protection of input low voltage
When a low UNREG power voltage is supplied, the low-voltage protection circuit is activated at the set value of
+10.5 V by the power microcomputer control and the camera body is shut down.
Once the low-voltage protection circuit is activated, the state is maintained. In that case, therefore, turn off the
power switch and replace the battery pack with a charged battery pack or take other appropriate actions.
• UNREG overcurrent detection
An overcurrent detection circuit consisting of IC100 is provided on the RE-321 board. The set value is approx. 4.3
A. Once overcurrent is detected, the circuit is not automatically reset even after the overcurrent is cleared, and
power must be turned on again.
• Protection of reverse power connection
If reverse input power voltage is supplied, Q102 on the RE-321 board is immediately turned off and the UNREG
power is shut off.
• Power-saving function in the standby state
While the camera power switch is turned off, the power microcomputer (RE-320 board: IC202) enters the sleep
mode to save power. Furthermore, Q106 on the RE-320 board is turned off to reduce current in the control system.
DC/DC converter function
Power supply is grouped into four blocks as shown below.
• CMOS/camera block system (Name: xx_IM)
• Audio/video signal system (Name: xx_DP)
• System controller system (Name: xx_SY)
• Media recording/playback system (Name: xx_MD)
Power in each block is turned on and off according to the power sequence control by the power microcomputer.
Short-circuit protection for each power supply system
Each power system monitors respective output voltages and the protection circuit is configured so that it works for each
block. When a short-circuit is detected even in a single block, this unit is shut down. The protection circuit is not
automatically reset even after the short-circuit is cleared, and power must be turned on again.
Battery pack information
• Battery pack authentication
A function to recognize the specified battery pack is provided to prevent major power accidents due to battery pack.
If an unspecified battery pack is installed, a message appears and then this unit is turned off.
• Battery pack information
In the specified battery pack, information such as the number of recycling times and the internal temperature can
be monitored internally. This allows the operation with detailed information about the battery, including information
whether the battery pack is damaged or has reached its lifetime.
PMW-300
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