线性稳压器的短路保护电路解析（Analysis of short-circuit protection circuit for linear voltage regulator）.docVIP

线性稳压器的短路保护电路解析（Analysis of short-circuit protection circuit for linear voltage regulator） Analysis of short-circuit protection circuit for linear voltage regulator A highly reliable linear regulator usually requires a limited current protection circuit to prevent permanent damage to the voltage regulator due to a short circuit load or overload. Current limiting protection is usually of 2 types: limited flow and reentrant current limiting. The former refers to limit the output current to the maximum value, the biggest drawback of this method is the internal loss of power regulator, and the latter refers to reduce the output voltage but also reduces the output current, its biggest advantage is when over current occurs, the power consumption in energy is relatively small, but in the short circuit of the load most, reentrant current limiting protection circuit is not completely off the regulator, still current flows, so that the power of the MOS energy consumption, accelerate the aging of. In view of the above situation, a short circuit protection circuit is designed based on the limited flow protection circuit to ensure that the MOS power is shut off under the short-circuit condition. In this paper, the working process and principle of the short circuit protection circuit are analyzed qualitatively and quantitatively, and the simulation results of Spectra based on TSMCO.18 mu m CMOS are given. 1 the principle of short-circuit protection circuit High reliability circuit short circuit protection circuit as shown in Figure 1, where VMP is the power of MOS linear voltage regulator tube, R1, R2 VMO and feedback resistance regulator; VMP tube is a current mirror circuit, VMO tube current copy power tube in a certain proportion, through the resistor R4 into test voltage transistor; VM1 level shift function, positive input end access by VM8 ~ VM12 MOS tube composed of a comparator (Vinp), negative input terminal of the comparator (Vinm) and output (0UT) VM13, VM14 diode connec