Discrete component class D power amplifier modulation board

The function of the Class D power amplifier modulation board
is to modulate the analog audio signal into a PWM signal. An external power board is required.
Full differential input and output are used
. BD & 1SPW & self-oscillation modes are supported
. Power limitation (limiting)
is supported. Frequency is adjustable.
Variable gain is supported .
The internal block diagram of 3116 is used for reference (3116 discrete version)
. There is currently no integrated chip for amplification, modulation, limiting and feedback (the feedback circuit of 3116 is not easy to adjust internally, the frequency is only fixed, and self-oscillation is not supported), so discrete components are used to make one.
This design has been verified and basically free of debugging after welding (the output DC offset will be automatically corrected, and the offset of 24V is <10mV. PLimit needs to be adjusted to limit the maximum duty cycle to 98% to prevent bootstrap undervoltage.)
The actual component parameters will be different from the figure, and need to be adjusted by yourself (for example, the gain of the front and rear stages, the front stage is recommended to be 0.5~10 times, and the rear stage is recommended to be 20 times).
Add a full-bridge (two half-bridges are also OK) amplifier circuit to amplify the signal of this modulation board, and send the signal to this modulation board for feedback to work normally.