| 摘要 |
A fast lossless power MOSFET gate capacitance (C) driver uses a 3-winding transformer (T) to secure clamping (N, Vc, D) of the turn-on voltage level by coupling of the winding (N1) in the capacitance charging circuit to that (N) across the clamping potential (Vc) in series with a clamping diode (D). A similarly coupled winding (N2) in the discharging circuit can ensure clamping of the turn-off level, both rise and fall starting at zero current and being sinusoidal. Alternatively, a high Q constant current charge can be used with the charging circuit switch (S1) DC isolated from the capacitance and using the magnetising current built up in the transformer. Instead of clamping the turn-off level, the discharging circuit can be switched (S2) during magnetising current build-up (S1) using a separate inductance to reverse the capacitance voltage in a half-wave resonant circuit.
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