The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 30, 2000
Filed:
Mar. 18, 1998
Louis Bennie Capps, Jr, Round Rock, TX (US);
Robert Christopher Dixon, Austin, TX (US);
Khuong Huu Pham, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus for driving a battery-backed up clock while a computer system is powered-down. The present invention uses an auxiliary power supply, VAUX, to power a microprocessor bus oscillator. The microprocessor bus oscillator is typically a high frequency, highly accurate oscillator. The microprocessor bus oscillator continues to run while the computer system is powered down, but is connected to a wall outlet. Thus, it can be used to synthesize an accurate time base to drive a battery-backed up clock input. A microcontroller, PAL, or other such circuit can be used to convert the high frequency signal from the microprocessor bus oscillator to a frequency suitable for the battery-backed up clock. Thus, a single oscillator is used to keep time for normal operations. Only when the system is moved, or when main power fails, is a battery backed-up crystal oscillator used to keep time. This minimizes the occurrence of timing errors, due to the system being turned off and back on.