Class D power amplifier composed of comparators and triodes ----- Class D Amplifier

Keywords: comparator and triode composed of D-class production Class D power amplifier composed of comparators and triodes Power supply voltage: Single power supply 9 ~ 24VDC (higher no tried) output power: 24V at 4.3 Europa test load up to 10W, at this time, power consumption is about 14W no-load current: 40mA (12V), 100mA (24V Harmonic distortion: 1kHz with 4.3 Euro test load, harmonic distortion ingredients mainly second and three harmonics, the quantity is close to each other; the total amount of the two is 1%. There is no significant change after the load is replaced with a bass horn. High-end frequency response (theoretical value): LC filter center frequency 30kHz, q = 1; closed-loop-3db bandwidth 19kHz low-end frequency response (theoretical value): use 1000uf electrolytic capacitance (doing experimental money) to do output coupling, -3db bandwidth 39Hz switching frequency: 200 ~ 300kHz variable. Overall structure: first use the LM311 plus the positive feedback resistor and the power buffer driving stage to form a high-power hysteresis comparator, and then add the RC integral negative feedback loop, which can generate the pulse width and frequency of input voltage modulation. oscillation. In order to eliminate the resonance of the output filter improve the frequency response characteristics, a small capacitor is performed between the output of the LC filter and the inverted end. Some miscellaneous test results have a certain amount of heat on the green magnetic ring, and the heat is hot, and it is estimated to be the "culpric juice" of power consumption. The power supply input has anti-reverse diodes, so it has directly input 9V AC on the internal semi-wave rectification. The communication sound is small, and only the ear is close to the horn; only the maximum output power will be greatly reduced. High frequency large signal characteristics and transient intermodulation distortion: Sine wave of 20K with sound card virtual oscilloscope (the highest frequency of the program can output, it has been highly obsoleted), the output amplitude is added to 60% of the VCC does not affect The sound; when it is added to 80%, the "咚" sound of Windows will become a metal sound. This amplitude is quite large, you can think that it will not encounter such a strong high frequency when you actually put your music. The schematic is as follows:

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