CLASS D POWER AMPLIFIER HAVING PROTECTION CIRCUIT

摘要

PURPOSE: A class D power amplifier having a protection circuit is provided to protect an operation of MOS transistors driven by a driver by blocking an operation of the driver according to short-circuit of a speaker output signal. CONSTITUTION: The first and the second drivers(202,204) input a PWM(Pulse Width Modulation) signal. An external circuit part(210) generates a speaker output signal by including MOS transistors and an LC filter comprising an inductor and a capacitor. An inverter(220) is driven by an output of the second driver. An output signal mapper(250) maps an operation range of the speaker output signal to an internal operation range of the class D amplifier. A low pass filter(230) demodulates an output of the inverter to an analog signal. The first and the second threshold area generation parts(240,260) set each of the output signal mapper output and the low pass filter output to be output within a threshold. And a protection circuit(270) judges whether to block an operation of the first driver.