Constant Voltage Switching Power Supplies

An LED switching power supply delivers constant power to the output load through high frequency switching operation. A switching regulator which can be used on its own or as part of a complete Power Supply switches a pass element, such as a MOSFET or bipolar junction transistor between its saturation and cut-off regions. The incoming power supply is chopped into a pulsed voltage, which is then smoothed out to match the required output using capacitors or inductors. Operating the in saturation and cut-off regions of the power transistor allows the switching power supply to deliver an efficiency of up to 95%. An SMPS can be implemented using the buck, boost, buck-boost, cuk, SEPIC, flyback or other topologies depending on the application scenario. In this mode of operation, the output of the converter circuit can be galvanically isolated from the input circuit to prevent electrocution.

switching power supplies are the only feasible option for medium to high power solutions which require a good efficiency, a high power factor and a low ripple output, or for applications which have to deal with wide input voltage ranges. The disadvantages with switching Power Supplies are that they are susceptible to electromagnetic interference (EMI) and they are also bulky and expensive.