Voltage transformer type high-voltage power supply unit, high-voltage power supply apparatus, and an image forming apparatus.

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric transformer type high voltage power supply which controls an output voltage of a piezoelectric transformer with high resolution with no micronization of a semiconductor process required, in order to solve the problems that are related ro digital control with the piezoelectric transformer that, if an internal operation clock is raised in speed, unwanted radiation noise and power consumption are increased, and micronization of semiconductor process is required, followed by raised development cost and longer development period, resulting in increase in chip cost.;SOLUTION: The drive frequency of a piezoelectric transformer is changed with a rough frequency resolution. It is determined whether or not a target set voltage V+α is obtained. If within that range, Duty is changed to reach a target set voltage by control. Thus, the operation clocks of CPU and ASIC are raised in speed, in other words, an output voltage can be controlled with high precision without micronizing a semiconductor process.;COPYRIGHT: (C)2012,JPO&INPIT