| 摘要 |
An electronic circuit is provided to improve the performance of a conventional power supply for driving a He-Ne laser. In order to avoid an undershoot of the DC current due to operation of the feedback circuit at driving start of the laser, a feedback interrupting circuit is provided in the power supply which compares a detected voltage with a first reference voltage smaller than a predetermined voltage to produce a resultant voltage when the detected voltage is larger than the first reference voltage. The resultant voltage is charged at a charging circuit with a charging time constant to produce a charged voltage. The charged voltage is compared with a second reference voltage having a predetermined voltage level, and the feedback circuit is prevented from producing the control signal during the time interval when the charged voltage is smaller than the second reference voltage.
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