EDAN M3 Service Manual page 20

Principle Introduction
This module converts 220V AC mains power supply or battery power into 5V, 12V and -12V DC
supplies to power other boards. If AC mains and battery coexist, the former take the priority to
power the system and charge the latter at the same time.
AC/DC
Converts high-voltage AC supply into low-voltage DC supply to power subsequent circuits and
charge the battery.
Battery Control Circuit
If AC supply and battery coexist, this circuit controls the output from AC/DC part to charge the
battery. If AC supply is disconnected, this circuit controls the battery to power the subsequent
circuits.
5V DC/DC
Convert the DC supply from the previous circuit into stable 5V DC supply to power other boards.
12V/-12V DC/DC
Convert the DC supply from the previous circuit into stable 12V/-12V DC supply to power other
boards.
Power Switch Circuit
Control the working status of 5V DC/DC and 12V DC/DC in order to control ON/OFF action of
the monitor.
M3 Vital Signs Monitor Service Manual
Battery
Power board
Power
control board
Figure2-3 Schematic Diagram of Power Board
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Fan