Patent ID: 6621308
Filing Date: 2003-09-16
Classification: H03K,H04L

Abstract:
A predrive circuit comprising:a predrive supply voltage; a predrive input stage responsive to a first bias current and operative to process a differential input signal and generate a first differential output signal therefrom; a first level shifter stage responsive to the first bias voltage and operative to level shift the first differential output signal downward to generate a second differential output signal therefrom; a differential gain stage responsive to the first bias voltage and operative to process the second differential output signal to generate a third differential output signal therefrom; a second level shifter stage connected to a pair of predrive output nodes and responsive to a second bias voltage based on a second bias current to level shift the third differential output signal downward as the predrive supply voltage increases to generate a predrive output signal at the pair of predrive output nodes; and a bias current supply circuit configured to generate the second bias current such that the second bias current is proportional to the square of the predrive supply voltage.