| 摘要 |
PROBLEM TO BE SOLVED: To completely detect an overcurrent even when detection time of a switch voltage is short. ! SOLUTION: A switching power supply unit has an overcurrent protection section 19 of low-side detection system thereon. The overcurrent protection section 19 includes: an overcurrent detection comparator 191 that compares a low-side switch voltage SWL to a threshold voltage VthL to create an overcurrent detection signal S3; latch sections (192 and 19A) that latch the overcurrent detection signal S3 to create a minimum off-time extension signal Sa; and a minimum off-time extension section 19X that extends a minimum off-time MINOFF according to the minimum off-time extension signal Sa. ! COPYRIGHT: (C)2014,JPO&INPIT |
