Toshiba Satellite P770, Manual

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1.5 Power Supply 1 Hardware Overview
Satellite P770/P775 Series Maintenance Manual [CONFIDENTIAL] 1-13
1.5 Power Supply
The power supply unit provides constant voltage (19V) for the system board and performs the
following functions:
1. Power input monitor
y
Checks whether the AC adapter (DC power supply) is connected to the computer.
y
Checks whether the battery pack is connected to the computer.
y
Monitors the DC power supply input voltage (AC Adapter output voltage).
2. Power supply's internal control
y
Turns on and off the battery pack charging power supply.
y
Issues a charging current instruction to the PWM control IC of the battery pack charging
power supply.
y
Controls the supply of DC power supply input (AC Adapter output) to the power supply
unit.
y
Controls the supply of power to the system block (load/logic circuit side).
y
Controls forced shutdown if the power supply malfunctions.
3. Logic circuit control
y
Instructs the gate array to enable/disable tuning the power on.
y
Controls power-on/off operation.
4. Status display
y
Turns on the Power LED (in White or Amber).
y
Battery indicator (in White or Amber).
y
DC-IN indicator (in White)
y
HDD accessing indicator (in White)
y
Wireless/BT indicator (in Amber)
y
Bridge media indicator (in White)
y
Logo indicator (in White)
5. External interface
y
Performs communication through the I2C bus (via the internal EC/KBC).