Power Supply - Toshiba M645-S4080 Maintenance Manual

1.5 Power Supply

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
Checks whether the AC adapter (DC power supply) is connected to the computer.
Checks whether the battery pack is connected to the computer.
Monitors the DC power supply input voltage (AC Adapter output voltage).
2. Power supply's internal control
Turns on and off the battery pack charging power supply.
Issues a charging current instruction to the PWM control IC of the battery pack charging
power supply.
Controls the supply of DC power supply input (AC Adapter output) to the power supply
unit.
Controls the supply of power to the system block (load/logic circuit side).
Controls forced shutdown if the power supply malfunctions.
3. Logic circuit control
Instructs the gate array to enable/disable tuning the power on.
Controls power-on/off operation.
4. Status display
Turns on the Power LED (White or Amber color).
Battery indicator (White or Amber color).
DC-IN indicator (White color).
5. External interface
Performs communication through the I2C bus (via the internal EC/KBC).
Transfers the power supply operation mode.
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