Michael Broach

US Patent:

6600639, Jul 29, 2003

Filed:

Jun 14, 2001

Appl. No.:

09/881933

Inventors:

Siew Siong Teo - Sunnyvale CA
Michael Eugene Broach - San Mateo CA
Richard Frank - Mountain View CA

Assignee:

National Semiconductor Corporation - Santa Clara CA

International Classification:

H02H 324

US Classification:

361 92, 361 18

Abstract:

An integrated circuit system and method provides a reliable low voltage reference including undervoltage lockout capabilities that prevent a premature or false response. A physical constant trigger circuit initiates a response based upon a physical constant (e. g. a stable point associated with a voltage summation in a transistor circuit with components configured to produce equal and opposite temperature coefficients). A response includes changing polarities of the transistor circuit at a predetermined inflection point. A comparator compares signals from the physical constant trigger circuit and determines when a change occurs in the response. A voltage divider provides a varying voltage to the physical constant trigger and when the voltage level corresponds to the physical constant it is utilized as the reference voltage. An input signal port conveys an input signal to the voltage divider and output port conveys an indication of the response (e. g. , a desired reference voltage is available).