Patent ID: 7095275

Claim:
A BTL (balanced transformer-less) amplifier system, comprising: a BTL amplifier including a differential amplifier for amplifying a voltage difference between first and second input terminals to output a first output voltage, and an inverting amplifier for inverting said first output voltage to output a second output voltage; a compensation input voltage application circuit capable of applying compensation input voltages at the same level to said first and second input terminals; a comparator for making comparison between first and second compensation output voltages which are respectively said first and second output voltages as a result of application of said compensation input voltages to said first and second input terminals; and a reference voltage control circuit for offset compensation, said offset compensation being realized by controlling a voltage at an output reference voltage input terminal of said inverting amplifier in response to an output signal from said comparator to minimize a difference between said first and second compensation output voltages.