Reducing latency when activating a power supply unit

A method for reducing latency using a charging module when activating a power supply unit (PSU) among a plurality of PSUs in a power supply system. The method includes: Receiving, by the PSU from a power input feed, input power; receiving, from a supply bus shared by the plurality of PSUs, a first controlled signal designating a status of the PSU as standby; disabling, in response to the first controlled signal, a switching regulator of the PSU; receiving, from a voltage rail of the supply bus, charge flowing through a resistor of the charging module to maintain a charge of an output capacitor of the switching regulator; receiving a second controlled signal designating the status of the PSU as active; enabling the switching regulator; outputting a voltage from the PSU through the charging module to the voltage rail; and charging the output capacitor using the PSU.