CLASS D POWER AMPLIFIER CHIP WITH DUTY CYCLE LIMIT FUNCTION AND DEVICE THEREOF

摘要

A class D power amplifier chip with a duty cycle limit function and a device thereof. The class D power amplifier chip (10) comprises a triangular wave module (400) a PWM module (100) a duty cycle detection module (200) and a logic control module (300). The PWM module (100) the duty cycle detection module (200) and the logic control module (300) are connected in sequence. The logic control module (300) is connected to the PWM module (100). Input differential audio signals and triangular wave signals generated by the triangular wave module (400) are converted into PWM signals with low pressure pulses by the PWM module (100) and the PWM signals are subjected to drive processing to generate high pressure pulses. A duty cycle of the PWM signals is detected in real time by the duty cycle detection module (200) and when the logic control module determines that the duty cycle of the PWM signals is larger than a preset maximum duty cycle the PWM module is controlled to stop operation which is equivalent to turning off audio output of the class D power amplifier device. The amplitude of output audio signals is limited and burnout of a loudspeaker due to overlarge amplitude is avoided.