| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique for limiting a current in a switch of a switching power supply. <P>SOLUTION: An example switching regulator circuit includes a power switch to be coupled to an energy transfer element of a power supply. A controller to generate a drive signal is coupled to be received by the power switch to control the switching of the power switch. A short on time period detector is included in the controller. The short on time period detector includes a comparator to detect whether or not a switch current flowing in the switch is larger than a current limitation. A frequency adjuster is also included in the controller and coupled to the short on time period detector. The frequency adjuster reduces, in response to the short on time period detector, a frequency of an oscillator so as to extend an off time period of the switch in response to detection of the switch current larger than the current limitation and when the on time period of the switch is equal to a sum of a rising blanking time period and a current limitation delay time period. <P>COPYRIGHT: (C)2012,JPO&INPIT |
