Gate drive circuit for insulated gate semiconductor device and flash controller using the circuit

Claim 2

A gate drive circuit for on-and-off-driving an insulated gate semiconductor device, comprising: first and second power terminals for providing a relatively high first voltage and a relatively low second voltage, respectively; first and second reverse-blocking switches connected in series between said first and second power terminals; an inductance element connected between a junction point of said first and second reverse-blocking switches and a gate of said insulated gate semiconductor device; and a control circuit for on-and-off-driving said insulated gate semiconductor device by on-and-off-controlling said first and second reverse-blocking switches, wherein said inductance element has inductance sufficient to generate LC resonance in cooperation with a gate input capacitance of said insulated gate semiconductor device, so that a gate voltage of said insulated gate semiconductor device is charged to a value higher than said first voltage.

Claim 3

A gate drive circuit in accordance with claim 1, wherein said first reverse-blocking switch includes a first transistor having a first electrode connected with said first power terminal, a second electrode coupled with said junction point and a control electrode connected with said control circuit, and said second reverse-blocking switch includes a second transistor having a first electrode coupled with said junction point, a second electrode connected with said second power terminal and a control electrode connected with said control circuit.

Claim 4

A gate drive circuit in accordance with claim 2, wherein said first reverse-blocking switch further includes a first diode having a first electrode connected with said second electrode of said first transistor and a second electrode connected with said junction point, and said second reverse-blocking switch further includes a second diode having a first electrode connected with said junction point and a second electrode connected with said first electrode of said second transistor.

Claim 5

A gate drive circuit in accordance with claim 3, wherein said first electrodes of said first and second transistors are collectors, said second electrodes of said first and second transistors are emitters, said first electrodes of said first and second diodes are anodes, and said second electrodes of said first and second diodes are cathodes.

Claim 6

A gate drive circuit in accordance with claim 2, wherein said control circuit comprises a first logical circuit connected with said control electrode of said first transistor and a second logical circuit connected with said control electrode of said second transistor, for turning on and off said first and second transistors complementarily.

Claim 7

A gate drive circuit in accordance with claim 1, further comprising a regenerative diode having an anode connected with said gate of said insulated gate semiconductor device and a cathode connected with said first power terminal, wherein said first power terminal supplies high power source voltage.

Claim 8

A gate drive circuit in accordance with claim 1, further comprising a regenerative diode having an cathode connected with said gate of said insulated gate semiconductor device and an anode connected with said second power terminal, wherein said second power terminal supplies low power source voltage.

Claim 9

A flash controller, comprising: first and second high voltage power terminals; an insulated gate semiconductor device on-and-off-driven by a gate drive circuit; a flash discharge tube connected in series with said insulated gate semiconductor device between said first and second high voltage power terminals; a flash energy storing capacitor connected in parallel to a series connected body composed of said insulated gate semiconductor device and said flash discharge tube; and a trigger circuit for triggering said flash discharge tube to start flash discharge, said gate drive circuit comprising first and second power terminals, for providing a relatively high first voltage and a relatively low second voltage, respectively; first and second reverse-blocking switches connected in series between said first and second power terminals; an inductance element connected between a junction point of said first and second reverse-blocking switches and a gate of said insulated gate semiconductor device; and a control circuit for on-and-off-driving said insulated gate semiconductor device by on-and-off-controlling said first and second reverse-blocking switches, wherein said inductance element has inductance sufficient to generate LC resonance in cooperation with a gate input capacitance of said insulated gate semiconductor device, so that a gate voltage of said insulated gate semiconductor device is charged up to a value higher than said first voltage.

Claim 10

A flash controller, comprising: first and second high voltage power terminals; an insulated gate semiconductor device on-and-off-driven by a gate drive circuit; a flash discharge tube connected in series with said insulated gate semiconductor device between said first and second high voltage power terminals; a flash energy storing capacitor connected in parallel to a series connected body composed of said insulated gate semiconductor device and said flash discharge tube; and a trigger circuit for triggering said flash discharge tube to start flash discharge, said gate drive circuit comprising first and second power terminals, for providing a relatively high first voltage and a relatively low second voltage, respectively; first and second reverse-blocking switches connected in series between said first and second power terminals; an inductance element connected between a junction point of said first and second reverse-blocking switches and a gate of said insulated gate semiconductor device; and a control circuit for on-and-off-driving said insulated gate semiconductor device by on-and-off-controlling said first and second reverse-blocking switches, wherein said inductance element has inductance sufficient to generate LC resonance in cooperation with a gate input capacitance of said insulated gate semiconductor device, so that a gate voltage of said insulated gate semiconductor device is charged up to a value higher than said first voltage.

Claim 11

A flash controller in accordance with claim 8, wherein said trigger circuit comprises a trigger capacitor coupled between said first and second high voltage power terminals, a switching means which is turned on in response to an emission start signal externally provided, and a trigger transformer having a primary coil connected in loop with said trigger capacitor and said switching means and a secondary coil connected with said flash discharge tube said flash controller further comprising means for maintaining a gate voltage of said insulating gate semiconductor device at such a level that said insulated gate semiconductor device can be turned on, prior to provision of said emission start signal.

Claim 12

A flash controller in accordance with claim 9, wherein said switching means includes a thyristor switch.

Claim 13

A flash controller in accordance with claim 8, wherein said first reverse-blocking switch includes a first transistor having a first electrode connected with said first power terminal, a second electrode coupled with said junction point and a control electrode connected with said control circuit, and said second reverse-blocking switch includes a second transistor having a first electrode coupled with said junction point, a second electrode connected with said second power terminal and a control electrode connected with said control circuit.

Claim 14

A flash controller in accordance with claim 11, wherein said first reverse-blocking switch further includes a first diode having a first electrode connected with said second electrode of said first transistor and a second electrode connected with said junction point, and said second reverse-blocking switch further includes a second diode having a first electrode connected with said junction point and a second electrode connected with said first electrode of said second transistor.

Claim 15

A flash controller in accordance with claim 12, wherein said first electrodes of said first and second transistors are collectors, said second electrodes of said first and second transistors are emitters, said first electrodes of said first and second diodes are anodes, and said second electrodes of said first and second diodes are cathodes.

Claim 16

A flash controller in accordance with claim 11, wherein said control circuit comprises a first logical circuit connected with said control electrode of said first transistor and a second logical circuit connected with said control electrode of said second transistor, for turning on and off said first and second transistors complementarily.

Claim 17

A flash controller in accordance with claim 8, further comprising a regenerative diode having an anode connected with said gate of said insulated gate semiconductor device and a cathode connected with said first power terminal, wherein said first power terminal supplies high power source voltage.

Claim 18

A flash controller in accordance with claim 8, further comprising a regenerative diode having an cathode connected with said gate of said insulated gate semiconductor device and an anode connected with said second power terminal, wherein said second power terminal supplies low power source voltage.