Hardware Structure
Theory of Operation
1 - 6
1.4.2
Power Board
The power board, shown in FIGURE 1-5, converts the input power (AC mains or battery) to
different working voltages for other boards. It also charges the battery.
FIGURE 1-5
Power Board Principle Diagram
The AC flows through the EMI filter and the rectifier and filter. The rectifier and filter converts
the AC to 16.8V DC voltage by the Flyback converter. The 16.8V DC voltage is the main
input to the DC/DC converters and charging circuit. The DC/DC converters convert 16.8V
DC to 12V, 5V, and 3.3V DC. The charging circuit charges the lithium battery. When the
Accutorr V is not connected to the AC mains, the battery supplies power to the DC/DC
converters.
The 16.8V DC output is protected against over-voltage and over-power. The 12V, 5V, and
3.3V DC outputs are protected against over-voltage, short-circuit, and over–current.
AC
INPUT
EMI
FILTER
RECTIFIER
& FILTER
RECTIFIER
& FILTER
FLYBACK
CONVERTER
CURRENT
DETECTION
PMW
CONTROLLER
BATTERY
CHARGING
CIRCUIT
DC/DC
CONVERTER
COUPLER
FEEDBACK &
ISOLATION
CIRCUIT
DC/DC
CONVERTER
SWITCH
CIRCUIT
DC/DC
CONVERTER
16.8V
12V
OUTPUT
5V
OUTPUT
3.3V
OUTPUT
0VP&0CP
0VP&0CP
0VP&0PP
PCON