| CPC H03K 17/08104 (2013.01) [H03K 17/145 (2013.01); H03K 17/6871 (2013.01); H03K 2017/0806 (2013.01)] | 7 Claims |
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1. A switch device comprising:
an output transistor;
an overcurrent protection circuit configured to be capable of performing an overcurrent protection operation in which magnitude of target current flowing in the output transistor is limited to a predetermined upper limit current value or less; and
a control circuit configured to be capable of controlling a state of the output transistor and capable of changing the upper limit current value among a plurality of current values including a predetermined first current value and a predetermined second current value less than the first current value,
wherein:
the control circuit is configured to be capable of changing the upper limit current value to the second current value after performing the overcurrent protection operation to limit the magnitude of the target current to the first current value or less when the magnitude of the target current reaches the first current value,
the output transistor is a field effect transistor having a plurality of channel regions that are controlled to an ON state or an OFF state independently from each other on the basis of a plurality of gate signals, and
the control circuit is configured to be capable of generating the plurality of gate signals, so that the target current flows through the plurality of channel regions in the overcurrent protection operation to limit the magnitude of the target current to the first current value or less, and that the target current flows through only a part of the plurality of channel regions in the overcurrent protection operation to limit the magnitude of the target current to the second current value or less.
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