1-16
420 Series
1.9
Power Supply
The power supply provides five kinds of voltages to the 420 series system board. The 420
series power supply has one microprocessor and it operates at 500 KHz. It contains the
following functions:
1.
Determines if the AC cable or battery is connected to the computer.
2.
Detects AC output and circuit malfunctions.
3.
Controls the LED icon and speaker.
4.
Turns the battery charging system on and off and detects a fully charged battery.
5.
Determines if the power can be turned on and off.
6.
Provides more accurate detection of a low battery.
7.
Calculates the remaining battery capacity.
The power supply output rating is specified in Table 1-8.
Table 1-8 Power supply output rating
DC
Regulation
Use for
Name
voltage
tolerance
(%)
System logic, FDD, HDD,
VCC
+5
±5
Display
CPU
CPUV
+2.9
±5
Flash ROM, PC card
12V
+12
±5
CPU, RAM, GA
B3V
+3.3
±0.3V
VRAM, GA
B5V
+4.7
±5