CRT power supply apparatus having synchronized high and low voltage power supply switching circuits

Abstract

A power supply circuit for a CRT display device includes a low-voltage power supply switching circuit for supplying power to a horizontal oscillation circuit of the CRT display device, and a high-voltage power supply switching circuit for supplying power to high-voltage circuits of the CRT display device. The low-voltage power supply switching circuit includes an oscillator and a switching transistor. The oscillator is triggered by an output of the horizontal oscillation circuit, and the conductive state of the switching transistor is controlled according to an output of the oscillator. The high-voltage power supply switching circuit includes a switching transistor. The conductive state of the switching transistor of the high-voltage power supply switching circuit is controlled according to an output of the low-voltage power supply switching circuit. As such, the switching operations of the low-voltage and high-voltage power supply switching circuits is carried out at a same frequency and in synchronism with the output of the horizontal oscillation circuit.

Dependencies are inferred from the claim text.