| 摘要 |
PURPOSE:To improve the charging efficiency and reduce the size and weight of a charging device, by providing a means for quickly discharging the electric charge accumulated in the capacitance between the gate and source of a MOSFET for high electric power at the same time as the switching pulse applised to the gate of the MOSFET shifts to an OFF state. CONSTITUTION:A DC water supply V is switched through a MOSFET2 for high electric power. The voltage V is boosted by a transformer 1 and supplied to an excitation charging circuit 100 through a diode D11. An accumulated charge dischargng circuit 16 has an astable multivibrator 161, an input resistor R162 and a transistor TR163 and carries out discharging of the electric charge accumulated in the capacitance between the gate and source electrodes of the FET2. The vibrator 161 performs free-running at a preset period and outputs timing pulses Q and inverted pulses Q', which are generated with opposite polarity. In consequence, the transistor TR163 is turned conductive at substantially the same timing as an OFF state of the gate voltage is started, so that the charge accumulated in the capacitance between the gate and the source of the FET2 is quickly discharged. Thus, it is possible to improve the charging efficiency and reduce the size and weight of the device. |
