Patent ID: 9621153
Date: 2017-04-11
CPC Classifications: H01L,H03K

Claim:
1. A gate control device configured to control a gate voltage to be applied to a gate electrode of a junction field effect transistor including a source electrode, a drain electrode, and the gate electrode, the transistor having a first threshold voltage at which the transistor is turned on, and a second threshold voltage at which conductivity modulation occurs in the transistor so as to make the gate voltage equal to or higher than the second threshold voltage when a forward current in a direction from the drain electrode toward the source electrode flows, so as to make a time variation in the gate voltage have a point from which a rate of the time variation starts decreasing at a voltage between the second threshold voltage and the first threshold voltage when the forward current to be shut down, and so as to maintain the gate voltage at a voltage between the second threshold voltage and the first threshold voltage for a predetermined time when the forward current is to be shut down, wherein the predetermined time is equal to or longer than 18 nanoseconds.