| 摘要 |
<p>A snubber circuit comprising two stages regulates the gate current of a MOSFET (12) in relation to the drain-to-source voltage at turnoff to clamp transient inductive voltages to a nondestructive level. At the onset of the turnoff, a current source (28) is activated to discharge the gate capacitance, and the snubber circuit controls the magnitude of such current in relation to the sensed drain-to-source voltage to stabilize the drain-to-source voltage at a nondestructive level. When the drain-to-source voltage approaches its limit value, a current injection circuit (76) supplies additional current to the gate (g) to sustain the MOSFET conduction, again in relation to the sensed drain-to-source voltage. When the inductive energy stored in the load (14) is substantially dissipated, the drain-to-source voltage falls; at such point, the current injection circuit (76) is disabled and the conduction of the current source is increased to complete the turnoff of the MOSFET.</p> |
