Substrate biasing circuit

Aiming at the technical problems in the prior art, the utility model provides a substrate biasing circuit which comprises a current mirror, an analog comparison circuit, a logic comparison circuit and a power tube which are sequentially arranged between a voltage input end VI N and a voltage output end VOUT. A positive feedback circuit formed by P1, P2, P3, P4, N2, N3, N4 and N5 is utilized to greatly improve the voltage lowering speed, so that the bias judgment time of the circuit is shortened; and the positive feedback also ensures the judgment function of the circuit when the difference between the VI N and the VOUT is small. The circuit judges that the speed of the biased substrate is greatly increased; when the magnitude difference between the input voltage VI N and the input voltage VOUT is not large, the circuit can also quickly judge the bias voltage. 本实用新型针对现有技术中存在的技术问题，提供一种衬底偏置电路，其包括依次序设置在电压输入端VI N和电压输出端VOUT之间的电流镜、模拟比较电路、逻辑比较电路和功率管。利用P1、P2、P3、P4、N2、N3、N4和N5形成的正反馈电路极大的提升了电压拉低的速度，这样就减小了电路判断偏置的时间；正反馈同时