Patent ID: 7714851

Claim:
A video line driver chip that operates using a single external positive supply voltage, comprising: a charge pump that uses the single external positive supply voltage to produce a negative voltage that has a lower amplitude than an amplitude of the positive external supply voltage; a plurality of amplifiers each of which are powered by the external positive supply voltage and the negative voltage produced by the charge pump; and a single reference voltage input that accepts a common external positive reference voltage for use by all of said amplifiers; wherein each said amplifier includes a first input, a second input and an output; wherein each said amplifier receives, at said second input of said amplifier, a voltage dependent on the common positive reference voltage accepted at said single reference voltage input; and wherein each said amplifier receives a different portion of a video signal at said first input of said amplifier; wherein each said amplifier outputs an amplified version of the received portion of the video signal, with its analog level shifted down by an amount substantially equal to the common external positive reference voltage accepted at said single reference voltage input, at said output of said amplifier; and wherein at least a significant portion of switching noise generated by the charge pump when producing the negative voltage is greater than 1 GHz, which is outside a frequency bandwidth of the video signal.