Considerations for Driving Power MOSFETs in High-Current, Switch Mode Regulators
The low on-resistance and high current carrying capability of power MOSFETs make them preferred switching devices in SMPS power supply design. However, designing with these devices is not as straightforward as with their bipolar counterparts. Unlike bipolar transistors, power MOSFETs have a considerable gate capacitance that must be charged beyond the threshold voltage, VGS(TH), to achieve turn-on. The gate driver must provide a high enough output current to charge the equivalent gate capacitance, CEI, within the time required by the system design.
AN22, MOSFET, Switch Mode Regulators