Patent ID: 9356518
Filing Date: 2016-05-31
CPC Classification: H02M

Claim Text:
1. An over-voltage protection circuit, applied to a switching voltage converting circuit, and used for detecting an abnormality of an upper bridge power switch in the switching voltage converting circuit, wherein the switching voltage converting circuit manipulates the upper bridge power switch, so as to convert an input voltage into an output voltage by an inductor, and a channel of the upper bridge power switch and the inductor are coupled to a phase end; comprising: a comparator, coupled to the switching voltage converting circuit, wherein when a voltage of the phase end is higher than a voltage limiting threshold, an output end of the comparator outputs a first voltage level; and a pulse width detection unit, coupled to the output end of the comparator, wherein when the output end of the comparator remains the first voltage level for a time period longer than a protection period, the pulse width detection unit outputs an over-voltage protection activation signal; wherein the switching voltage converting circuit further includes a lower bridge power switch, and when the pulse width detection unit outputs the over-voltage protection activation signal, a channel of the lower bridge power switch is conducted, and a current loop is formed between the channel of the upper bridge power switch and the channel of the lower bridge power switch.