Switching Power Amplifier With Feedback For Improving Total Harmonic Distortion

A low distortion and high efficiency switching power amplifier is proposed. This circuit is designed for micropower low voltage hearing instruments. We use feedback to reduce the total harmonic distortion (THD) and the DC output bias current. The experimental results show that the proposed circuit has 0.24% total harmonic distortion and 91% power efficiency while the d.c. output bias current is 12 muA at 1.5V supply voltage