Patent ID: 7012342

Claim:
A power supply system comprising: power supply bus lines; a power supply unit for providing voltages to the power supply bus lines; a power supply control unit for providing control signals indicating desired voltages on the power supply bus lines; switching circuits connected to the bus lines, each switching circuit receiving the control signal from the power supply control unit and connecting one of the voltages from the power supply unit to a given one of the power supply bus lines to maintain one of the desired voltages on the given power supply bus line based on the control signal; wherein each of the switch circuits comprises a pair of photo isolator relays, wherein each photo isolator relay having a first photo isolator input terminal coupled for receiving a given one of the control signals from the power supply control unit, and a relay output having a first terminal connected to a given one of the power supply bus lines, wherein a first one of the photo isolator relays of each pair has a second output terminal connected to receive a given one of the voltages from the power supply unit; and wherein a second one of the photo isolator relays of each pair has a second input terminal connected to a first power supply potential.