CPC H02M 1/088 (2013.01) [B60R 16/033 (2013.01); H02H 7/1213 (2013.01); H02M 1/32 (2013.01); H02M 3/158 (2013.01); H03K 17/082 (2013.01); H02M 1/0009 (2021.05); H02M 1/0025 (2021.05)] | 20 Claims |
1. A switching regulator control circuit for use in a switching regulator that includes: a first switch having a first terminal thereof connected to a first application terminal to which an input voltage is applied; a second switch having a first terminal thereof connected to a second terminal of the first switch and having a second terminal thereof connected to a second application terminal to which a voltage lower than the input voltage is applied; and an overcurrent sensor configured to sense an overcurrent through the second switch based on a potential difference between the first terminal and the second terminal of the second switch, the switching regulator control circuit generating a switching signal for controlling ON/OFF operation of the first switch, the switching regulator control circuit comprising:
a fault detector configured to detect, based on a duty ratio of the switching signal or a variable correlated to the duty ratio and included in a control signal used to generate the switching signal, a fault state where the duty ratio falls outside a normal modulation range; and
a fault protector configured to stop switching of the first switch to turn the first switch OFF when the fault detector detects the fault state,
wherein:
the switching regulator control circuit is configured to inhibit any pulse from occurring in the switching signal during a period in which an overcurrent is sensed by the overcurrent sensor,
the fault detector is configured to detect the fault state based on pulses with a pulse width outside a normal range occur in the switching signal,
an upper limit of the pulse width of the switching signal is limited to a fixed width, and
a plurality of values are set as the fixed width, and any one of the plurality of values can be selected as the fixed width.
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