A Low-Dropout Regulator With Smooth Peak Current Control Topology for Overcurrent Protection

The proposed low-dropout (LDO) regulator with a smooth peak current control (SPCC) circuit can be simultaneously controlled by using an error amplifier to regulate output voltage and a peak current controller as a means to limit its current level. The SPCC circuit can be switched smoothly between these two control mechanisms by detecting the information of load current and the dropout voltage. Measured results show that overcurrent protection can make the pass device operate as a current source while the load current exceed the peak current level. Moreover, the control mechanism can return to error amplifier control when load current becomes smaller than the limiting current, thus ensuring output voltage to be close to the rated value. Output voltage is stable and varies smaller than 15 mV when a 160 mA load current step or a 2 V supply voltage step is placed on this LDO regulator.