| 摘要 |
PURPOSE:To suppress a spike voltage or a noise to small values by providing a switching circuit for switching the time constant of a gate voltage drive circuit. CONSTITUTION:When a drive signal Si2 becomes L level, a transistor 6 is turned ON, a gate voltage drops in response to the time constant determined by the storage capacitor of a P-channel power MOS transistor 7 and a resistor 5, and the transistor 7 is turned OFF. When the signal Si2 then becomes H level, the transistor 6 is turned OFF, the gate voltage of the transistor 7 slowly rises in response to the time constant determined by the storage capacitor and the resistor 4, and is turned OFF. Thus, the gate voltage is controlled by a large time constant by the ON and OFF of the transistor 7 to suppress the spike voltage, then switched to a small time constant to prevent a longitudinal current due to the erroneous operation of the gate voltage. |
