Patent ID: 7915955

Claim:
A bias balancing circuit for balancing an output voltage outputted by an amplifier module which has a variable gain, and the bias balancing circuit comprising: a comparator, electrically connected to the amplifier module, for comparing the output voltage and a reference voltage, to generate a comparison signal; and a voltage selector, electrically connected to the comparator and the amplifier module, for generating a selected voltage according to the comparison signal, wherein the voltage selector comprises a current selector, electrically connected to the comparator, for generating a selected current according to the comparison signal; and a current-voltage transducer, electrically connected to the current selector and the amplifier module respectively, for generating the selected voltage according to the selected current, wherein when the variable gain is changed to result in an offset from the output voltage to the reference voltage, the bias balancing circuit is capable of balancing the output voltage toward the reference voltage by the selected voltage.