Principle of DC/DC converter

The output voltage is compared with the reference voltage through a voltage divider resistor to form a feedback. When the output voltage decreases and is lower than the reference voltage, the output of the comparator flips and triggers the oscillation circuit to start working. The oscillation circuit outputs a fixed-time pulse to control the conduction of the MOS tube. Otherwise, the MOS tube will be cut off. The turn-on is controlled by the oscillator, and the cut-off time depends on the load. In this way, the output voltage can be controlled.