Cheap and beautiful NE555 switching power supply

Today we use NE555 for everyone (NE555 is one of the 555 series of timing ICs, the 555 series IC's pin function and application are compatible, but the model is different because of its price, its stability, province Electricity, the oscillation frequency that can be generated is not the same.) Be an inexpensive switching power supply.
As shown in the figure, a step-up switching regulator power supply circuit composed of 555 is used. In the circuit, the transistor BG1 is used as a switching adjustment tube; the operational amplifier IC1 constitutes a comparison amplifier; and the 555 time base circuit is connected to an astable multivibrator. The oscillator generates a sawtooth voltage on C1 (Vmin=1/3Vz, Vmax=2/3Vz, the frequency is determined by W1 and C1) and is sent to the non-inverting input of comparator IC1. The sampled voltage is sent to the inverting input of the comparator. . The duty cycle of the IC1 output rectangular waveform is controlled by the sampling voltage. When the output voltage is a stable value, the sampling voltage is a value between 1/3Vz and 2/3Vz. When the output voltage rises (or falls) for some reason, the sampling voltage rises (or falls), causing the duty cycle of the IC1 output rectangular wave to decrease (or increase), and the on-time is shortened (or increased). The output voltage drops (or rises) to achieve a stable output voltage. Adjust W to control the output voltage.