Electrical characteristics of MOSFETs (Charge Characteristic Q_g/Q_gs1/Q_gd/Q_SW/Q_OSS)

Gate charge

Because the Gate (G) input terminal of a MOSFET is insulated, the amounts of charge Q seen from the Gate are important characteristics. Figure 1.5 illustrates the definitions of gate charge characteristics.

Total gate charge Q _g

The amount of charge to apply voltage (from zero to designated voltage) to gate

Gate-source charge 1 Q _gs1

The amount of charge required for a MOSFET to begin to turn on (before dropping drain-source voltage)

Gate-drain charge Q _gd

The amount of gate charge charged in the Miller plateau

Gate switch charge Q _sw

The amount of charge stored in the gate capacitance from when the gate-source voltage has reached V _th Until the end of the Miller plateau

Output charge Q _oss

Drain-source charge

The definition of the gate charge amount is shown in the figure below.

Data sheet description