Patent ID: 6998824
Filing Date: 2006-02-14
Classification: H02M,Y02B

Abstract:
1. A power supply circuit comprising: a DC—DC conversion circuit including a high side transistor and a low side transistor connected in series between a power supply voltage and a reference potential and producing a direct current output voltage as a PWM controlled output which is obtained by turning “on” and “off” each of the transistors with each PWM signal; a detection circuit for detecting a level of an intermediate node potential at a junction point of the high side transistor and the low side transistor after turning “off” the high side transistor, wherein the detection circuit is directly connected to the high side transistor and the low side transistor at the junction point so as to directly detect the intermediate node potential therefrom, wherein the detection circuit includes: means for turning “on” the low side transistor when the intermediate node potential becomes below or equal to a predetermined potential.