Controlling power efficiency of an information processing device

A method comprising:

• converting an input voltage into a predetermined first output voltage for charging a battery pack with first power including first voltage in response to receiving a charge control signal for charging the battery pack;
• converting the first power including the first voltage stored in the battery pack into a predetermined second output voltage for powering an information processing device with second power including a second voltage in response to receiving a discharge control signal for the battery pack;
• suppling the second power including the second voltage to the information processing device;
• and
• determining the input voltage.

A system comprising:

• an information processing device that consumes second power including a second voltage, comprising:
• a battery pack that stores first power including a first voltage;
• a voltage converter that:
• converts an input voltage into a predetermined first output voltage for charging the battery pack with the first power including the first voltage in response to receiving a charge control signal for charging the battery pack, and
• converts the first power including the first voltage stored in the battery pack into a predetermined second output voltage for powering the information processing device with the second power including the second voltage in response to receiving a discharge control signal for the battery pack,
• wherein the information processing device consumes the second power supplied by the voltage converter;
• a controller that determines the input voltage;
• and
• a power adapter external to the information procession device that supplies power to the voltage converter.