| 摘要 |
PURPOSE:To facilitate a noise countermeasure by narrowing the ON or OFF period of a reference pulse in response to the instantaneous value of a load current, thereby maintaining a switching frequency constant. CONSTITUTION:When a load current reaches the upper limit value during the ON period of a transistor 2 with the output pulse of a phase regulator 11 varying at the ratio of ON/OFF in response to the current command value as a reference, the ON period is narrowed, next ON signal is outputted when the output of the regulator 11 becomes high level, the OFF period is narrowed when the load current reaches the lower limit value during the OFF period of the transistor 2, and the next OFF signal is outputted when the output of the regulator 11 becomes low level. Thus, the ON/OFF frequency of the transistor 2 becomes the same as the output frequency of the regulator 11, the noise generated when the transistor 2 operates ON or OFF becomes constant, thereby facilitating a noise countermeasure. |
