The amplifiers capable of supplying high voltage output for piezo actuators are large, heavy, and have low efficiency, but the developed PWM Power Amplifier module is specialized for voltage amplification, enabling high performance and high reliability, and also has high efficiency, all in a compact size. Key technologies are the high efficiency architecture circuit, advanced protection circuit and the use of high reliability parts. The efficiency of the PWM Amplifier is almost determined by the load current and does not depend on the output voltage.