Class D - Class D audio amplifier is a switching amplifier or PWM as previously explained. By applying the Switching model can reduce power loss in the final amplifier and allow for 90% - 95% efficiency. The input audio signal is used to modulate the PWM carrier signal that drives the final amplifier. Before being fed to the speaker first pass the Low Pass Filter (LPF) to eliminate the high frequency of the PWM carrier.
Then what is the function of the comparator in the class-d amplifier?
Comparator serves to digitize the audio input signal by comparing the audio signal with the sawtooth signal. The result of this comparison circuit is a digital copy signal from the analog audio input signal. Low-frequency components of digital signals represent audio input signals, while high-frequency components of digital signals are not used or ignored.
But the schematic that I shared this only in the error amp section is not complete, this I made because to replace the damaged error amp section per block. So just install this circuit to power-d class, a class-d power amplifier that can be used is like:
IN= Audio Input
V-=Power Voltage Amplifier (-V)
V+= Power Voltage Amplifier (+)
B= To Base 2N5401
Part list for the schematic above you can download from the link at the end of this post.
PCB Layout Design
BoM (Bill of Materials)
PCB Layout PDF