| 摘要 |
PROBLEM TO BE SOLVED: To effectively suppress ringing pulses arising in a boosting circuit. SOLUTION: This boosting circuit is equipped with a coil 1 where a battery voltage VB is applied to one end, an n-channel MOSFET 3 which is connected between the other end of the coil 1 and ground potential, a diode 5 whose anode is connected to a drain of the FET3, and a capacitor 7 which is connected between the cathode of the diode 5 and ground potential. The boosting circuit generates a voltage higher than the battery voltage VB in the terminal of the capacitor 7 by charging the capacitor 7 by a counter electromotive force which is generated in the coil 1 at OFF of the FET3 by turning on or off the FET 3 repeatedly by means of a control IC9. Herein, the control IC9 operates the FET 3 in an active region only for a certain time tb after a specified delay time ta after turning off the FET3 after the finish of a switching control period when the FET3 is turned on or turned off repeatedly, whereby the ringing pulses generated in the drain side of the FET3 is suppressed. COPYRIGHT: (C)2006,JPO&NCIPI
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