Control of computer AC adapter output voltage via battery pack feedback

A computer system, comprising:

• a rechargeable battery;
• a monitoring circuit coupled to said rechargeable battery for measuring the present voltage and current at the terminals of said rechargeable battery;
• a battery microcontroller coupled to said monitoring circuit and implementing a recharging routine generating a desired voltage for the terminals of said rechargeable battery;
• said battery microcontroller further generating an adjustment signal based on the present battery terminal voltage and current and the desired battery terminal voltage;
• an adjustable output AC adapter having an output voltage signal line coupled to a terminal of said rechargeable battery, and a control input for altering the output voltage signal of said AC adapter;
• and
• a dither control circuit coupled to said battery microcontroller and said control input of said AC adapter, said dither control circuit receiving the adjustment signal and communicating a corresponding control signal to said control input of said AC adapter.

A method for controlling the voltage at the terminals of a rechargeable battery in a computer system incorporating an adjustable output AC adapter, the computer system further comprising a monitoring circuit for measuring the voltage and current at the terminals of the rechargeable battery, a battery microcontroller for implementing a recharging algorithm, and a dither control circuit for adjusting the output of the AC adapter, the method comprising the steps of:

• retrieving the present voltage and current at the terminals of the rechargeable battery as determined by the monitoring circuit;
• calculating the desired voltage and current at the terminals of the rechargeable battery as determined by the recharging algorithm;
• generating an adjustment signal based on the present voltage and current and the desired voltage and current;
• and
• communicating the adjustment signal to the dither control circuit to modify the AC adapter output voltage such that the adjusted voltage at the terminals of the rechargeable battery approaches the desired voltage.