Video signal processing circuit and computer system

Abstract

A video signal processing circuit, in which a horizontal synchronizing signal is separated from an input analog video signal by a synchronism separating circuit, whether a “H” period of the horizontal synchronizing signal continues for more than a prespecified period of time or not is checked by a synchronizing signal monitoring counter, and power supply to an A / D converter is controlled thereby according to a result the confirmation.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,621,523 B2. The reissue applications are application Ser. Nos. 11 / 229,447 and the present application, all of which are reissues of U.S. Pat. No. 6,621,523 B2, and all of which are commonly assigned to the assignee of the present invention.[0002]The present patent application is a Continuation of Reissue patent application Ser. No. 11 / 229,447, filed Sep. 16, 2005, which is a Reissue Patent Application of U.S. Pat. No. 6,621,523 B2 to Toshiro Obitus, entitled “Video Signal Processing Circuit and Computer System,” filed on Feb. 21, 2002, and issued on Sep. 16, 2003. <?insert-end id="INS-S-00001" ?>[0003]ThisThe patent application isthat issued as U.S. Pat. No. 6,621,523 B2 to Toshiro Obitus was a continuation of U.S. application Ser. No. 09 / 040,424, filed Mar. 18, 1998, now allowed.[0004]ThisThe patent application isthat issued as U.S. Pat. No....

AI Technical Summary

Benefits of technology

[0011]It is a first object of the present invention, putting attention to a received video signal itself, to provide a video signal processing circuit which can prevent wasteful power consumption in the circuit as a whole by eliminating unnecessary A / D conversion according to a video signal.

[0012]It is a second object of the present invention to provide a computer system which can prevent wasteful power consumption in the system as a whole by applying therein the video signal processing circuit which achieves the first object.

[0013]With the present invention, power supply for A / D conversion is controlled according to a synchronizing signal to an input analog video signal, so that unnecessary A / D conversion is eliminated according to a video signal, and with this feature, it is possible to prevent wasteful power consumption in a circuit as a whole.

Problems solved by technology

In this battery-driven system, a driving time is limited because of correlation between a battery life and a driving time.

For this reason, even when it is conceivable from the view point of an A / D converter and a video signal processing circuit as a peripheral unit thereof or of the system as a whole that, even when the sampling driving is not needed, power is supplied to an A / D converter and the power is wastefully consumed, which makes an operating time of the whole system shorter.

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