Power Supply - Toshiba T4900CT Manual

1.7

Power Supply

The power supply supplies five kinds of voltages to the T4900CT system board. The
T4900CT power supply has one microprocessor and it operates at 500 KHz (power off) or 20
MHz (power on). It contains the following functions:
1. Determines if the AC adapter or battery is connected to the computer.
2. Detects DC output and circuit malfunctions.
3. Controls the speaker and the brightness.
4. Controls the Battery capacity icon, Power on icon, and AC adapter icon on the
status indicator panel.
5. Turns the battery charging system on and off and detects a fully charged battery.
6. Determines if the power can be turned on and off.
7. Provides more accurate detection of a low battery.
8. Calculates the remaining battery capacity.
The power supply output rating is specified in table 1-5.
Use for
System logic, FDD, HDD
RS-232C, Flash ROM
Display
RAM, CPU
RS-232C
1-14
Table 1-5 Power supply board output rating
DC
Name voltage
(V)
VCC +5
12V +12
DSPV +9.5 to +23
B3V +3.3
M12V –7 to –12.6
Regulation Maximum
tolerance current
(%) (mA)
±5 2,200
±5 120
– 4.02 W
±5 2,200
– 10
Ripple
(mV)
100
240
–
60
–
T4900CT