Patent ID: 8508901

Claim:
An overcurrent detection circuit comprising: a detection transistor whose current value is controlled according to a control voltage applied to a gate terminal of an output transistor, the output transistor being configured to control an electrical power supply to a load; a potential difference setting unit for which a potential difference of output voltages is controlled according to the current value of the detection transistor; and a first transistor whose current value is controlled according to a potential difference between its gate and source terminals, the potential difference between the gate and source terminals of the first transistor being controlled by the potential difference setting unit, wherein the overcurrent detection circuit detects an overcurrent based on the current value of the first transistor, and the potential difference setting unit comprises: a first depletion type transistor, a supply voltage being applied to a drain terminal of the first depletion type transistor, and gate and source terminals of the first depletion type transistor being connected to the gate terminal of the first transistor; a second transistor, drain and gate terminals of the second transistor being connected to a node between the gate and source terminals of the first depletion type transistor and the gate terminal of the first transistor; and a second depletion type transistor provided on a current path between the source terminal of the first transistor and the source terminal of the second transistor, gate and drain terminals of the second depletion type transistor being connected to a source terminal of the detection transistor, and a source terminal of the second depletion type transistor being connected to an output terminal to the load.