Patent ID: 7205727

Claim:
A power supply circuit, comprising: a coil having first and second ends, the coil having supply voltage applied to the first end thereof; a first element connected between the second end of the coil and ground, the first element being a switching element; a second element configured to rectify current to be supplied to a load in accordance with voltage generated at a connection of the coil and the first element, and to supply the current to the load; a driver circuit configured to switch at least the first element; a third element connected in series between to the load and base potential, the third element being a switching element; a resistor connected in series between the load and the third element; and a power supply stop circuit configured to switch off the third element so as to stop supplying the current to the load in accordance with an external signal, wherein when the power supply stop circuit switches off the third element, the driver circuit is caused to switch off the first element through a feedback loop for controlling the current to the load so that supplying power to the load is stopped, the feedback loop being provided between the driver circuit and a connection of the load and the resistor.