Power Supply Circuit for Selectively Supplying Power to a Vehicle Accessory

摘要

According to one embodiment of the present invention, a power supply circuit is provided for selectively supplying power to a vehicle accessory. The power supply circuit may be comprised of a switch coupled to a power line from the vehicle battery and to a power input of the accessory, and a control circuit coupled to the switch. The control circuit may monitor the battery voltage and selectively supply power from the battery to the accessory in response to the battery voltage. The control circuit may supply power from the battery to the accessory when the battery voltage changes at least a predetermined amount over a time period. The control circuit may comprise a microprocessor that adaptively learns signatures in the battery voltage occurring when the engine is running in order to provide power from the battery to the accessory as if the power were supplied from the ignition.