Patent ID: 8232680
Filing Date: 2012-07-31
Classification: H02J

Abstract:
1. An apparatus that provides alternating current (“AC”) power source redundancy, the apparatus comprising: a first input module configured to receive a first AC power input waveform from a first power source, the first input module determining whether the first AC power input waveform is present by sensing a first direct current (“DC”) bias voltage generated from the first AC power input waveform; a second input module configured to receive a second AC power input waveform from a second power source, the second input module determining whether the second AC power input waveform is present by sensing a second DC bias voltage generated from the second AC power input waveform; a first switch connecting the first input module to a common node; a second switch connecting the second input module to the common node, wherein a power waveform at the common node provides power to an output node; a switching logic module that controls the first switch and the second switch, wherein a rectified AC waveform derived from the first AC power input waveform is applied to a first opto-coupler to provide the first DC bias voltage to the switching logic module and a rectified AC waveform derived from the second AC power input waveform is applied to a second opto-coupler to provide the second DC bias voltage to the switching logic module, the first and second opto-couplers electrically isolating the first and second AC power input waveforms from the switching logic module, and wherein the first switch comprises a first relay and second switch comprises a second relay, the first and second relays comprising electromagnetic relays; and a DC power source, a first logic switch, a second logic switch, and a third logic switch, a coil of the first relay connected to the DC power source and to the first logic switch such that closing the first logic switch closes the first relay, a coil of the second relay connected to the DC power source and to the second logic switch such that closing the second logic switch closes the second relay, the third logic switch connected to a drive input to the second logic switch such that closing the third logic switch prevents the second logic switch from closing, wherein