| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the possibility of allowing a noise voltage pulse on a gate driving circuit to unnecessarily turn on a MOSFET switch by adding a nonlinear break down diode and the parallel circuit of a capacitor to a gate driving circuit. SOLUTION: In order to improve the gate drive circuit, the nonlinear break down diode (constant voltage diode) CR4 and the parallel combination of a capacitor C1 are included. By the adding of this parallel combination, Q1 is supposed to be N channel power MOSFET and a negative DC voltage is added to between the gate and source of a switch to increase a protecting degree to the unexpected contact turn on of power MOSFET. In this case, a noise spike should amount to a gate-source threshold voltage before MOSFET is commutated to on by exceeding the quantity of negative bias. The introduced negative bias is provided with a protecting degree to prevent the occurrence of an attempt only for maintaining a gate to be zero voltage. |
