| 摘要 |
<p>In an electronic flash device according to the present invention, a main condenser (101) charged by a high power voltage supply (100) is connected in series with a flash discharge tube (102) and an IGBT (104). To the gate of the IGBT (104), bias voltage is applied by a gate bias power supply (105') before a flash start signal is provided, and the IGBT (104) waits, in an ON state that the flash discharge tube (102) is triggered in response to the flash start signal. When predetermined time elapses after the flash discharge tube (102) starts to flash, a flash stop circuit (106') changes gate bias voltage of the IGBT (104) so as to shift the IGBT (104) to an OFF state by predetermined time width. Application of high voltage to the IGBT (104) is made for extremely short period of time in the OFF state. Consequently, requirement for high breakdown voltage and less leaking current is eased. In addition, a gate controlling circuit becomes simple.</p> |
