Chin Chuan Chien

US Patent:

7529317, May 5, 2009

Filed:

Sep 27, 2005

Appl. No.:

11/236191

Inventors:

Chin Ming Chien - Irvine CA, US
Bojko F. Marholev - Irvine CA, US

Assignee:

Broadcom Corporation - Irvine CA

International Classification:

H04L 27/00

US Classification:

375316

Abstract:

Embodiments of the present invention provide an oscillator circuit having a steady output frequency that is independent of the supplied voltage. This oscillator includes a Schmitt trigger circuit which may be implemented within an integrated circuit of a wireless terminal or other like portable electronic device. The Schmitt trigger circuit receives a threshold voltage input and a second voltage input. The Schmitt trigger circuit generates an output voltage equal to either a first output voltage or a second output voltage based on the results of comparing the threshold voltage input to the second voltage input. An RC network may be coupled to the output of the Schmitt trigger circuit and is operable to supply the second voltage input to the Schmitt trigger circuit. A voltage divider network also couples to the output of the Schmitt trigger circuit wherein the threshold voltage input is proportional to the first output voltage reduced by the voltage divider network based on the output voltage of the Schmitt trigger circuit.

US Patent:

20090196375, Aug 6, 2009

Filed:

Apr 21, 2009

Appl. No.:

12/427618

Inventors:

Chin Ming Chien - Irvine CA, US
Bojko F. Marholev - Irvine CA, US

Assignee:

BROADCOM CORPORATION - IRVINE CA

International Classification:

H03K 9/00
H03K 3/00

US Classification:

375316, 327205

Abstract:

Embodiments of the present invention provide an oscillator circuit having a steady output frequency that is independent of the supplied voltage. This oscillator includes a Schmitt trigger circuit which may be implemented within an integrated circuit of a wireless terminal or other like portable electronic device. The Schmitt trigger circuit receives a threshold voltage input and a second voltage input. The Schmitt trigger circuit generates an output voltage equal to either a first output voltage or a second output voltage based on the results of comparing the threshold voltage input to the second voltage input. An RC network may be coupled to the output of the Schmitt trigger circuit and is operable to supply the second voltage input to the Schmitt trigger circuit. A voltage divider network also couples to the output of the Schmitt trigger circuit wherein the threshold voltage input is proportional to the first output voltage reduced by the voltage divider network based on the output voltage of the Schmitt trigger circuit.