SWITCHING POWER SOURCE DEVICE, SEMICONDUCTOR DEVICE, AND AC/DC CONVERTER

摘要

The switching power source device obtains a desired DC voltage by controlling the current flowing through a coil by turning on and off a switching element by a PWM control. In the PWM ON period to turn on the switching element by the PWM control, the switching power source device is enabled to switch the switching element by a first pulse signal whose cycle is shorter than the PWM cycle and whose pulse width is gradually increased, in a first period just after the start of the PWM ON period. Further, the switching power source device is enabled to switch the switching element by a PWM signal based on the PWM control after the first period in the PWM ON period has elapsed. According to this approach, it is possible to reduce the harmonic noise.

主权项

1. A switching power source device for controlling the current flowing through a coil by turning on/off a switching element by a PWM control to obtain a desired DC voltage,
wherein in the PWM ON period to turn on the switching element by the PWM control, the switching control of the switching element is enabled by a first pulse signal whose cycle is shorter than the PWM cycle based on the PWM control and whose pulse width is gradually increased, in a first period just after the PWM ON period is started, and wherein the switching control of the switching element is enabled by the PWM signal based on the PWM control after the first period has elapsed.