HIGH VOLTAGE POWER SUPPLY

PROBLEM TO BE SOLVED: To provide a high voltage power supply capable of accurately detecting discharge even if it occurs at the transformer of a low voltage side. SOLUTION: A high voltage power supply 5A includes high voltage transformers 15a-15d each of which has primary windings and secondary windings wherein the secondary windings are directly connected together and the secondary winding on the lowest voltage side is connected to a ground node, resonance circuits 11a and 11b that are connected to an input power supply VIN and include FETQ1, Q2 for parallel-driving the primary windings, an output voltage detecting circuit 17 connected to the secondary winding on the highest voltage side, a PWM modulation circuit 22 which compares a voltage detected by the output voltage detecting circuit 17 with a voltage BV of reference sawtooth wave, and PWM-controls the FETQ1, Q2 according to the comparison results, peak rectification circuits 13a and 13b for detecting outputs of the resonance circuits 11a and 11b, and a differential voltage absolute value circuit 14 which differentially detects output results from the peak rectification circuits 13a and 13b and stops operation of the PWM modulation circuit 22 according to the detection results. COPYRIGHT: (C)2011,JPO&INPIT