Abstract: An electrical power supply device includes a DC-DC power convertor receiving an input voltage and producing an output voltage, a first and second port connected to the DC-DC power convertor supplying electrical power to a first and second consumer device, and a device controller connected to the DC-DC power convertor, the first and second port. The memory device controller stores instructions to command the DC-DC power convertor to produce the output voltage between a first voltage threshold and a higher second voltage threshold when only the first consumer device is connected to the first port. The memory stores additional instructions which commands the DC-DC power convertor to produce the output voltage at the first voltage threshold when the first consumer device is connected to the first port and the second consumer device is connected to the second port.

Abstract: A motor vehicle accessory control is capable of reversibly activating a DC motor to operate a vehicle door lock, window, sun roof or similarly operated device through a relay controlled H-switch arrangement. The control is provided with an automatic control circuit in a module having input and output terminals but only a single power terminal, which provides either positive power or ground to the module. The opposite power connections are made from the module through the activating relay coils of the H-switch motor drive circuit. A manual switch may be provided for alternative manual reversible activation of the relays; and the circuit provides priority of manual over automatic operation. Neither the manual switch nor the module circuit is capable of activating both relays simultaneously; therefore, a reliable power connection is always available for the module through at least one of the relay activating coils.