US 5,672,958 AGranted

Method and apparatus for modifying feedback sensing for a redundant power supply system

AssigneeDell USA, L.P.

InventorsAlan E. Brown, Nathan Wiscombe

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Abstract

A feedback sensing system including a control circuit for detecting power failure of either power supply, and for controlling first and second switch circuits to modify the feedback sensing path of the other supply to the output load. In this manner, when one power supply fails, the feedback sensing path of the other power supply is rerouted to the output node to directly monitor and regulate the voltage across the load. Each switch circuit preferably operates to switch between two nodes along the respective output paths of the power supply, including a first node located before the current control device and a second node located between the current control device and the load. In one embodiment, each switch circuit includes two switches operated in a mutually-exclusive manner. In another embodiment, each switch circuit includes a relatively low value resistive device coupled between the output sense input and the first node, and a switch coupled between the output sense input and the second node for swamping the resistive device when activated or otherwise turned on.

Claims20

Dependent claims

A feedback sensing system for controlling power provided to a load of a power supply system, the power supply system including first and second power supplies, each having at least one power output and an output sense input for sensing a node for feedback control, the power supply system further including first and second current control devices coupled in series along first and second output paths, respectively, between the respective outputs of the first and second power supplies and the load, the feedback sensing system comprising:

a first switch circuit for coupling to the output sense input of the first power supply for selecting between first and second nodes along the first output path, wherein said first node is located between the output of the first power supply and the first current control device, and the second node is located between the first current control device and the load;
a second switch circuit for coupling to the output sense input of the second power supply for selecting between first and second nodes along the second output path, wherein said first node is located between the output of the second power supply and the second current control device, and said second node is located between the second current control device and the load;
and
a control circuit coupled to control said first and second switch circuits to select said first nodes of the first and second output paths during normal operation, said control circuit for detecting failure of the first and second power supplies, wherein if the first power supply fails, said control circuit switches said second switch circuit to select said second node of the second output path, and if said second power supply fails, said control circuit switches said first switch circuit to select said second node of the first output path.

1 more element

A redundant power supply system for providing power to a load, comprising:

a first power supply having a first power output and an output sense input;
a first current device having a current path coupled in series between said first power output and the load for controlling current to the load from said first power supply;
a first switch circuit for coupling said output sense input of said first power supply to either a first node located between said output of said first power supply and said first current device, or to a second node located between said first current device and the load;
a second power supply having a second power output and an output sense input;
a second current device having a current path coupled in series between said second power output and the load for controlling current to the load from said first power supply;
a second switch circuit for coupling said output sense input of said second power supply to either a third node located between said output of said second power supply and said second current device, or to a fourth node located between said second current device and the load;
and
a control circuit coupled to said first and second power supplies and said first and second switch circuits, wherein if said first power supply fails, said control circuit switches said second switch circuit to said fourth node from said third node, and wherein if said second power supply fails, said control circuit switches said first switch circuit to said second node from said first node.

5 more elements

Dependencies are inferred from the claim text.