The gate driver is essential in power electronics because of two basic reasons. First, at high frequency switching applications the switching time is less which means that in order to charge/discharge the mosfet capacitance fast, more current is required. The output current of most optocouplers is not enough to drive the mosfet properly. Secondly, most of the optocoupler output is limited to under 10 V which means that they can operate a mosfet near its threshold voltage, This results in high R_ds resulting in heating the mosfet.



Several chips are available for mosfet driving, that deals specifically with the special topologies. In this post TC4424 (datasheet) is explained to drive a low side n channel mosfet. I have checked this ic with switching frequency as high as 125 kHz.

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It has two inputs and two outputs. It is a non inverting gate driving ic which means that output follows the input. To avoid heating this ic following points should be kept in mind.

1. Unused input pin must be grounded. 
2. The V_dd must be decoupled with local ceramic capacitor.