Tan V Ho

US Patent:

6438429, Aug 20, 2002

Filed:

Dec 3, 1999

Appl. No.:

09/454796

Inventors:

Tan Thanh Ho - Santa Clara CA
Scott William Mitchell - San Jose CA
Andrew Nakao - Fremont CA
Ngo Thanh Ho - San Jose CA
George Kwan - Sunnyvale CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

G06F 126

US Classification:

700 22, 713340

Abstract:

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.

US Patent:

6560714, May 6, 2003

Filed:

Dec 3, 1999

Appl. No.:

09/454676

Inventors:

Tan Thanh Ho - Santa Clara CA
Scott William Mitchell - San Jose CA
Andrew Nakao - Fremont CA
Ngo Thanh Ho - San Jose CA
George Kwan - Sunnyvale CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

G06F 126

US Classification:

713340, 713310

Abstract:

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.

US Patent:

6564333, May 13, 2003

Filed:

Dec 3, 1999

Appl. No.:

09/454468

Inventors:

Tan Thanh Ho - Santa Clara CA
Scott William Mitchell - San Jose CA
Ryan Hirth - Windsor CA
Ngo Thanh Ho - San Jose CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

G06F 126

US Classification:

713340, 713310

Abstract:

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.