| 摘要 |
PURPOSE:To obtain a high voltage only when it is needed without supplying the high voltage from an external part by generating a boosting voltage only when it is needed with being synchronized to an input signal. CONSTITUTION:An input pulse is let to a timer 3 and the pulse of a constant time width T is obtained with being synchronized to the rising edge of the input pulse. Further, this waveform-shaped pulse signal is let to an inverter 5 and inputted to the base of a transistor 6 with inverting the phase of the pulse signal. When the output voltage of the inverter 5 is low, the transistor 6 is disconnected. At such a time, a current is stopped being flowed from a coil 11 to the transistor 6 and a high fly-back voltage, which is higher than a power source voltage, is generated to an output terminal 9. Thus, the boosting voltage can be obtained only when it is needed with being synchronized to the input signal. |
