An anti-clipping protection system for multilevel class-D amplifier

Class D amplifier is a popular device because of its high power delivery efficiency. However, during practical application, the “clipping” problem aggravates power loss and reduces reliability. We therefore present an anti-clipping protection system incorporated with proposed PWM-based multilevel class-D amplifier to enhance the audio quality and reliability. The multilevel technique consists of a time-division-adder and a multilevel converter to generate and deliver multilevel signal as stairway. In addition, the pulse density adjustment technique dynamically adjusts the power delivery according to the results of the anti-clipping detection circuit. Under the protection operation, experiments results show that the intensity and excessive heat of “clipping” will be greatly reduced over 25% and 40% which demonstrate the effectiveness of proposed scheme.