2-5. Auto discharge function of LDO regulators

An electronic system consists of multiple ICs and circuits. For the system to work properly, it is necessary to set a power supply sequence, i.e., the order in which to supply power to the constituent ICs and circuits. A relatively large capacitor is connected to the V_OUT pin of an LDO regulator in order to smooth the output voltage. After the LDO regulator is turned off, this smoothing capacitor remains charged for a while, depending on the supply current of the subsequent IC or circuit. This makes it difficult to set the required power supply sequence. When an LDO regulator turns off, the auto discharge function discharges the smoothing capacitor quickly via the internal N-channel MOSFET connected between the V_OUT and GND pins, thereby simplifying power supply sequencing.