| 摘要 |
PURPOSE:To provide a simple and inexpensive device for detecting a precise main circuit DC voltage which is applicable to a serve motor control device by counting the time width of the rectangular wave output from a diode for halve-wave rectifying the output voltage of the secondary side coil of a pulse transformer. CONSTITUTION:A main circuit capacitor 2 has a main circuit DC voltage on both ends, and a pulse transformer 6 is switched by a switching circuit 7, whereby an output voltage VCC is provided. Since this output voltage is fed back by a feedback circuit 7 to change the switching duty, a fixed voltage can be regularly kept. For the waveform of the input voltage V2 of a counter 5, since the time width is contracted according to an increase in the main circuit DC voltage, when the load of the VCC is supposed to be constant, and reversely extended according to the decrease, the time width during one period is counted by the counter 5, and converted into a voltage by a microcomputer 4, whereby the main circuit DC voltage can be detected. |
