| 摘要 |
PROBLEM TO BE SOLVED: To provide a driver circuit with a small size and a simple configuration.SOLUTION: A driver circuit includes: normally-on transistors Q1 and Q2; a control circuit 1 controlling the transistor Q1 in response to a control signal &phgr;1; a control circuit 2 controlling the transistor Q2 in response to a control signal &phgr;2; a capacitor 1 connected between power-supply nodes 1c and 1d of the control circuit 1; a power supply 7 connected between power-supply nodes 2c and 2d of the control circuit 2; a switch element 5 connected to the power-supply nodes 1d and 2d; and a control circuit 3 turning on the switch element 5 when an output voltage VO becomes approximately 0 V. Thus, a negative voltage V3 can be supplied to the control circuit 1 without separately providing an insulating power supply. |
