Design, analysis and implementation of A/D converter for switching power supply

The A/D conversion circuit is an important part of switching power supply equipment, and the circuit design has a great influence on the conversion accuracy. This paper mainly discusses the current mode circuit, gives the difference between it and voltage mode, and studies the design idea and circuit of the A/D conversion circuit. In this paper, the current mode circuit is composed of basic components, and the A/D conversion of the switching power supply is realized by switching current mode. The reason of A/D conversion error is that when the current mirror is not strictly matched, it is caused by the limited input and output resistance of MOS tube, and an operational amplifier is added between the drain and gate of the current mirror to improve the A/D conversion accuracy. The results show that the current mode is used to realize A/D conversion, which has low power consumption and fast conversion speed.