3com Corporation

Tan Thanh Ho

Scott William Mitchell

Ngo Thanh Ho

George Kwan

Andrew Nakao

Ryan E Hirth

A circuit and method thereof for arbitrating between a first power source and a second power source in a computer system peripheral device such as a network adapter (e.g., a network interface card) that is connected to multiple power sources. The circuit includes a field effect transistor (FET) and a diode integral with the FET coupled between the first power source and the second power source. The FET is adapted to conduct current from the second power source when power is not available from the first power source, and to substantially prevent current from flowing from the first power source to the second power source. The circuit also includes a voltage regulator coupled between the first power source and the second power source, adapted to regulate voltage such that a voltage from the first power source and a voltage from the second power source are approximately equal.

Peripheral device power management circuit and method for selecting between main and auxiliary power sources or from third power source

A circuit and method thereof for arbitrating between a plurality of power sources connected to a computer system peripheral device. The circuit includes a first circuit subassembly coupled to a first power source and a second power source. The first circuit subassembly conducts current from the first power source when power is not available from the second power source, and otherwise conducts current from the second power source. The circuit also includes a second circuit subassembly coupled between the first circuit subassembly and a third power source. The second circuit subassembly conducts current from the third power source when the third power source is available and otherwise conducts current from the first circuit subassembly. The second circuit subassembly comprises a first component, a second component and a third component. The first component is coupled to the third power source and the first circuit subassembly. The first component conducts current from the first circuit subassembly when power is not available from the third power source and otherwise substantially does not conduct current. The second component is coupled to the third power source and the first component. The second component conducts current from the first component when power is available from the third power source and otherwise substantially does not conduct current. The third component is coupled to the first component, the second component and the third power source. The third component conducts current from the third power source when power is available from the third power source.

Power management for a peripheral component interconnect environment with auxiliary power

A circuit and method thereof for indicating availability of a power source other than a first power source in a computer system peripheral device (such as a network adapter) connected to a plurality of power sources including. The circuit includes a circuit subassembly coupled to the first power source and a second power source. The circuit subassembly conducts current from the first power source when power is not available from the second power source and otherwise conducts current from the second power source. A first component is coupled to the circuit subassembly and conducts current when the second power source is available; otherwise, it does not conduct current. A second component is coupled to the circuit subassembly and to the first component. The second component conducts current when the first component is conducting current and otherwise does not conduct current. An output lead is coupled to the second component, and the output lead provides a signal indicating the second power source is available.

Growing community of inventors

Santa Clara, CA, United States of America

Tan Thanh Ho