| abstract |
An object of the present invention is to reduce the on-resistance during high temperature operation of a junction field effect transistor (JFET) and improve the operating characteristics at high temperature. An output switching circuit gives an output switching instruction to a second drive circuit when a temperature detected by a temperature detecting device is equal to or higher than a predetermined threshold temperature. Thus, the second drive circuit drives the MOSFET 35, the rising voltage (forward voltage drop) V F over the gate voltage V GS is applied to the JFET 10, JFET is bipolar operation. Thereby, an increase in the on-resistance of the JFET 10 at a high temperature can be suppressed. [Selection] Figure 5 |