Abstract: A system comprises a plurality of the hot swapping type uninterruptible power supply module and a plurality of conventional power supply. A HSUPS comprises a battery module and a controller module. A conventional power supplies is connected with an external AC power source and converts into DC voltage to provide power to the electronic system and/or to charge the HSUPS when necessary. The battery module holds the energy needed to power the electronic system during the absences of a conventional power supply and/or external AC power source. The controller module controls the operation to charge the battery, discharge the battery, switch off the HSUPS, or be standby. The controller module has the ability to detect for any failure event. The HSUPS provides power to the electronic system when the external AC power source is interrupted and when all of the conventional power supplies are removed from the system.

Abstract: The commutator for a bridgeless PFC circuit is characterized in that a synchronous half-wave rectifier is connected between a bridgeless PFC boost circuit and an AC power source and is coupled to the two terminals of the AC power source. The synchronous half-wave rectifier contains a first synchronous transistor, a second synchronous transistor, and a control circuit.

Abstract: The power supply comprises a bridge rectifier connected to an AC source; a boost converter series-connected to the bridge rectifier comprising an inductance coil; a filter capacitor series-connected to the boost converter; a DC/DC converter connected to a load; a hold-up-time enhancer connected to and positioned between the filter capacitor and the DC/DC converter; and a virtual by-pass system parallel-connected to the hold-up-time enhancer comprising an induction coil inductively coupled to the inductance coil of the boost converter. As such, voltage is induced on the induction coil by the inductance coil in the boost converter and the virtual by-pass system parallel-connected to the hold-up-time enhancer is thereby turned on and off.