SEMICONDUCTOR CIRCUIT AND SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To shorten the time from the start of switching until a predetermined current flows when switching an active element connected to a load from off to on.SOLUTION: An LED array 18 is electrically connected to an MOSFET20 capable of driving the LED array 18 which becomes on when a predetermined voltage is inputted. A semiconductor circuit 24 includes a calculation amplifier 30, a voltage drop circuit 36, and a switch 42. A non-inverting input terminal of the calculation amplifier 30 is applied with a reference voltage V. The voltage drop circuit 36 lowers a voltage outputted from the calculation amplifier 30. The switch 42, during a first period in which the MOSFET20 is applied with the predetermined voltage from the calculation amplifier 30 and is turned on, inputs a voltage according to a predetermined current that flow when the MOSFET20 is turned on into an inversion input terminal of the calculation amplifier 30, and during a second period while the MOSFET20 is off, inputs a voltage having been dropped by the voltage drop circuit 36 into the inversion input terminal.