Power Sources and Supplies: World Class Designs

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Chapter 8

(only) by Rdrive

and Cgd . Finally, in T3, the current starts falling toward zero. The

gate voltage falls exponentially (as an RC circuit)—down to Vt , at which moment, the

end of subinterval T3 is declared. The transition is now complete as far as the switch

is concerned. But after that, during T4, the RC exponential discharge continues down

to 10% of the initial gate drive amplitude. As before, driver dissipation occurs over

T1  T2  T3  T4, whereas crossover occurs during T2  T3.

8.9 Gate Charge Factors

A more recent way of describing the parasitic capacitor-based effects in a MOSFET is

in terms of