Pulse-Shaped MOSFET Driver

The breadboard was constructed, and two waveforms were measured. These waveforms are shown in Fig. 9.8 the top trace is the output gate drive pulse, and the bottom trace is the input voltage to the 555. 

This circuit was also constructed in IsSpice, PSpice, and Micro-Cap. The resulting waveforms are shown in Figs. 9.9, 9.10, and 9.11, respectively. 

Generally, a linear SPICE primitive capacitor is not the best way to model the nonlinear capacitance of a MOSFET. The capacitance of the MOSFET s gate is dependent on the gate-to-source voltage, and to a lesser extent, the drain-to-source voltage. However, the fixed capacitance used in this simulation is adequate for our purposes. 

Advantages Good drive current capability, reduced turn-on switch transient currents Disadvantages Higher parts count than other solutions, slower tum-on that creates higher power dissipation in the MOSPET 

File names puls.sh (IsSpice), pls shp2 (PSpice), pls shp3 (Micro-Cap) 

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