Patent ID: 7227588

Claim:
A clamping system for clamping a video signal, the clamping system comprising: a charge-pump unit ( 10 ), which receives and clamps a potential of an analog video signal, wherein the charge-pump unit ( 10 ) is composed of a first charge pump circuit ( 11 ) and a second charge-pump circuit ( 12 ); a programmable gain amplifier (PGA) ( 20 ) coupled to the charge-pump unit ( 10 ) to amplify the clamped analog video signal; an analog to digital converter ( 30 ) coupled to the PGA ( 20 ) to convert the amplified analog video signal to a digital video signal; and a digital clamping controller ( 40 ) coupled to the A/D converter ( 30 ), wherein the digital clamping controller ( 40 ) detects whether a sync tips signal is contained in the digital video signal output from the A/D converter ( 30 ), and based on the detected result to control the charge-pump unit ( 10 ) to clamp the analog video signal by using a strong burst signal or a weak burst signal.