An improvement of the current–voltage conversion technique in over-current sensing circuit for low-power low dropout linear voltage regulators

Abstract

In this paper, a resistance-less over-current sensing circuit using current---voltage conversion technique for CMOS low dropout linear voltage (LDO) regulators with PMOS as pass device is proposed. The scheme of this over-current sensing uses the I---V conversion technique. This improvement results in an elimination of the body effect and reduces the deviation of the current limiter. The resulting current clamp value only varies from 190 to 250 mA when the supply voltage varies from 2.7 to 5 V. The total quiescent current of the LDO is 3.51 uA at the 5 V supply voltage. The current consumption of the over-current sensing circuit is about 1 uA.