Chopper PWM-Based Class-D Amplifier
Nuriel Rozsa (TU Delft - Electrical Engineering, Mathematics and Computer Science)
Q. Fan – Mentor (TU Delft - Electronic Instrumentation)
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Abstract
Class-D amplifiers are widely used in audio applications that require a high power efficiency. A high PSRR is beneficial when the power supply contains significant audio band content. Due to mismatches present in the feedback, these can dominate the PSRR of the class-D amplifier, provided the amplifier has sufficient loop gain. No literature has been found that describes a solution to improving the PSRR and CMRR across the full audio band. This work proposes chopping of the input and feedback resistors in a class-D to address this issue. With this technique's application, a >100dB PSRR and CMRR across the audio band is achieved.