| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem associated with a current turn-on/off switch using a field effect transistor (FET): the FET is destroyed by an excessive current or excessive voltage generated when a current is turned on or off.SOLUTION: The value of a gate resistor is so controlled that the following is implemented: when a current is turned on, the value of the gate resistor 110 is a value large sufficient to prevent a gate voltage from producing a parasitic oscillation by a gate stray capacitance and a gate tray inductance when a gate voltage rises and is small sufficient to exclude the possibility that FET operates in an active region within a gate voltage rise time and this leads to destruction, and when a current is turned off, the gate resistance value is large sufficient for eliminating the possibility that gate voltage rapidly drops and a source-drain voltage produces overshoot due to a counter electromotive force. |
