Patent ID: 8502418

Claim:
An auto-shut off circuit comprising: a relay comprising a coil and a switch; a voltage conversion device comprising an input terminal and an output terminal; first to third diodes; a capacitor; and a first transistor and a second transistor; wherein a first terminal of the switch is connected to a power supply, a second terminal of the switch is connected to the input terminal of the voltage conversion device, a first terminal of the capacitor is connected to the second terminal of the switch, a second terminal of the capacitor is connected to a base of the first transistor and a collector of the second transistor, a collector of the first transistor is connected to an anode of the first diode, a cathode of the first diode is connected to the input terminal of the voltage conversion device, an emitter of the first transistor is connected to a first terminal of the coil, a second terminal of the coil is grounded, an emitter of the second transistor is connected to the output terminal of the voltage conversion device, a base of the second transistor is connected to an electronic device, the output terminal of the voltage conversion device is connected to an anode of the second diode, a cathode of the second diode is connected to an anode of the third diode, a cathode of the third diode is connected to the electronic device.