Power supply circuit and control method for the same

摘要

According to an embodiment, a power supply circuit is provided. The power supply circuit includes a switching transistor which is controlled to be ON/OFF by a PWM signal, and a mode switching control circuit configured to switch a control mode between peak current mode control and valley current mode control depending on the length of an ON time of the PWM signal which drives the switching transistor.

主权项

1. A power supply circuit comprising a first switching transistor in which a main current path is connected between an input terminal and an output terminal, and configured to adjust an output voltage by controlling ON/OFF of the first switching transistor by a PWM signal applied to the first switching transistor, the power supply circuit comprising:
a mode switching control circuit having a first mode and a second mode and configured to switch between the first mode and the second mode depending on the length of an ON time of the PWM signal; wherein the first mode is configured to control pulse width of the PWM signal by a predetermined timing signal and a timing when a feedback current becomes larger than a preset first control value, and the second mode is configured to control pulse width of the PWM signal by the timing signal and a timing when the feedback current becomes smaller than a preset second control value.