| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit for a semiconductor switching element configured to generate an appropriate negative voltage in simple configuration in the semiconductor switching element.SOLUTION: A half bridge circuit 2 for feeding power to a coil 1 is formed from GaN elements 3 and 4. A negative power supply circuit 13 of a control circuit 6 of the GaN element 4 is a series circuit of a capacitor 10 and a diode 12. As a clamp circuit, a Zener diode 11 is connected in parallel to the capacitor 10. By turning on the GaN element 3, the coil 1 is electrified and during a dead-time period, the GaN element 4 is reversely conducted by a load current. The capacitor 10 is iteratively charged by a forward voltage Vf of the GaN element 4. When a terminal voltage Vc of the capacitor 10 reaches a clamp voltage, charging is stopped. A negative voltage of the capacitor 10 is given to a gate drive circuit 8, such that a gate voltage can be supplied while the GaN element 4 is turned off. |
