| CPC H03K 17/0822 (2013.01) [G05F 1/573 (2013.01); H02H 3/087 (2013.01); H03K 2217/0027 (2013.01)] | 18 Claims |
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1. A semiconductor integrated circuit device, comprising:
an output transistor connected between a voltage input terminal to which a DC voltage is input and a voltage output terminal;
a control circuit that controls on/off of the output transistor;
an overcurrent detection circuit configured to detect an overcurrent state of an output current by determining whether a current equal to or greater than a first predetermined current value flows through the output transistor, based on the current flowing through the output transistor;
a retry circuit that includes a timer circuit using charging and discharging by a capacitor and that generates and outputs a signal for intermittently turning off the output transistor in response to the overcurrent detection circuit detecting the overcurrent state continuously for a first period of time; and
a first external terminal,
wherein:
the timer circuit includes a constant current source, a current mirror circuit that copies a current from the constant current source, the capacitor that is charged and discharged by a current from the current mirror circuit and that is connected to the first external terminal as an external capacitor, and a comparator whose input is connected to the first external terminal,
the first period which is set by a capacitance value of the capacitor is longer than a period during which a rush current flows, the rush current flowing immediately after the output transistor is turned on,
the timer circuit starts measuring a time of the capacitor charged by the constant current source in response to the overcurrent state being detected, and, when the first period has elapsed, the output transistor changes from on to off, and when a second period has elapsed, the output transistor changes from off to on, and the control circuit repeats control of turning on and off the output transistor until the overcurrent state is resolved, and
the current mirror circuit turns off and on by output signal of the comparator.
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