| 摘要 |
PURPOSE:To improve the response characteristic of a whole control system, by adding a diode to an error amplifier as a limit circuit. CONSTITUTION:A diode D1 which acts as a limiter circuit is installed to an OP amplifier Q1 which works as an error amplifier in a negative constant-current high voltage power source which exercises frequency control of a high voltage output. When such an arrangement is made, a transistor (Tr) Q3 is switching- driven by a frequency from a V/F converter 1 through a soft start circuit 5 and generates a high voltage output through a TrQ2, if a high voltage output turning on signal is inputted into a terminal 6. The high voltage output is supplied to a high voltage load RL through a rectifier circuit 2. If the high voltage output is not generated, the diode D1 operates and the output VP3 of the OP amplifier rises. The output VP3 stabilizes when the electric potential VP1 at the point P1 of the output VP3 becomes equal to that VP2 of the point P2 and the dynamic range of the OP amplifier output VP3 is narrowed by setting the lower limit value to VP2-0.6V. |
