Patent ID: 8072342
Filing Date: 2011-12-06
Classification: H02H

Abstract:
1. An overcurrent protection circuit connected between a voltage input and a voltage output of an electronic device to protect against excessive current between the voltage input and the voltage output, the overcurrent protection circuit comprising: a relay comprising a coil and a normally closed switch, wherein the switch is opened in response to the coil being powered on, wherein a first terminal of the switch is connected to the voltage input via a first resistor, a second terminal of the switch is connected to the voltage output; an pnp transistor, wherein an emitter of the pnp transistor is connected to the voltage input, a collector of the pnp transistor is connected to a first terminal of the coil via a second resistor, a second terminal of the coil is grounded, a series circuit including a third, a fourth, and a fifth resistors in series is connected between the first terminal of the switch and ground, a base of the pnp transistor is connected to a node between the third resistor and the fourth resistor; and a break-over element having a break-over voltage, wherein a first terminal of the break-over element is connected to the first terminal of the switch, a second terminal of the break-over element is connected to a node between the fourth resistor and the fifth resistor.