Automatic contrast control apparatus according to the child Damn, control system

摘要

The automatic contrast control apparatus is a cathode ray tube to decrease the contrast adjusting voltage through the automatic contrast limiting (ACL) circuits if the contrast adjusting voltage input via the I ² C communication line exceeds a normal range according to the disclosed I ² C control scheme to allow automatic adjustment of the contrast of the video signal such as R, G and B supplied.; Automatic contrast control apparatus in accordance with the present invention I ² C control according to the method outputs a reference oscillation signal by receiving the horizontal sync signal and vertical sync signal outputted from the video card, and to adjust the contrast of the R, the video signal of G and B contrast adjustment voltage comprises the I ² horizontally for supplying a signal to the high-voltage circuit and bias circuit receives the microcomputer, a reference oscillation signal and a horizontal / vertical synchronization signal from the microcomputer and a video card for outputting the C data, and vertical oscillation for signal processing and the detection of the contrast adjusting voltage includes a horizontal and FBT and an I ² C data input from the microcomputer is connected to the output terminal of the vertical oscillation signal processor for generating a high voltage to be supplied to the cathode ray tube and detecting the contrast adjusting voltage in some cathode ray contrast control signal to R, G, and adjust the gain of the video signal at the B input from the video card gwaneu A video preamplifier output to and connected to a video pre-amplifier is operated by a control signal outputted from the video pre-amplifier according to the contrast adjustment voltage comprises the I ² C data output from the microcomputer to pull down the contrast adjusting voltage It consists ACL circuit.; Accordingly, I ² of this invention, if it exceeds the detection result, a normal range of the contrast adjusting voltage comprising the I ² C data signal output from the microcomputer to drive the ACL circuit is connected independently to the video preamp output from the microcomputer C to pulldown the contrast adjusting voltage in the data signal R, and provides an effect of adjusting the contrast of the G and B video signals.