Class D Power Amplifier with Time-based Circuits ----- NE555 Class D Power Amplifier

Class D Power Amplifier with Time-based Circuits, NE555 Class D Power Amplifier Keywords: Class D power in time base circuit The switch type (Class D) audio power amplifier designed by the author uses the time base circuit NE555 to push the two-channel power amplifier TDA1521, which can output 30 W × 2 power at a time than 85% efficiency at ± 16V. The electrical principle is shown. The NE555 time base Ic is received as a oscillation frequency 120 kHz, a square wave oscillator that duty 50%. When the audio signal is input by 5 foot, the output signal duty cycle of the 3 foot will make linear variations as the input audio signal is low. The signal is reduced by the filter circuit composed of L1 to L4, C1 to C4 after the TDA1521 power is enlarged. The quick recovery diode D1 to D4 is used to protect TDA1521 from the damage of the L1 ~ L4 self-sensing potential. Since the IC is working in a switching state, high power can be output efficiently. When debugging, the audio signal is not entered. At this time, the output terminal of the TDA 1521 should be 0V, otherwise it is the time-based circuit static output asymmetric square wave, and the RP should be adjusted to correct. Then the input signal speaker should vote. When the output power is 30 W × 2, the device is 30 W × 2, the actual efficiency is more than 85%, and the harmonic distortion is less than 0.8%, and the effect is an intention of exactly.

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