| 摘要 |
PURPOSE:To make a device compact and cheap, by providing a circuit for detecting the terminal voltage of a capacitor and a circuit for controlling the width of switching pulse of a DC conversion circuit by the output of the detection circuit. CONSTITUTION:Two outputs inverse in phase to each other are sent out of an oscillator 9 and applied to input terminals of comparators 12a, 12b through integrators 11a, 11b. The output of an inversion amplifier 8 is applied to the other input terminals of the comparators. The outputs of the comparators 12a, 12b and the oscillator 9 are supplied to AND circuits 13a, 13b, the outputs of which are supplied as control signals to switching transistors 1a, 1b. The turn-on period of the switching transistors is short when the terminal voltage of a capacitor 6 is low, but long when the terminal voltage is high. As a result, the capacitor 6 is charged always by an optimal current. |
