Patent ID: 6515536
Filing Date: 2003-02-04
Classification: H03L

Abstract:
A common mode feedback circuit comprising:an input differential transistor pair receiving a differential input, the input differential transistor pair producing a differential output current; a reference current source providing a common mode reference current; a current mirror having a first current provided by the common mode reference current, and a second current provided by the differential output current, the second current being controlled by the current mirror to be equal in magnitude to the common mode reference current; a difference wire, the difference wire extending from between the input differential transistor pair and the current mirror, the difference wire providing a current path for a current equal in magnitude to the difference between the magnitude of the first current and the magnitude of the second current; wherein the reference current source comprises a reference differential transistor pair receiving a reference signal input; wherein the reference signal input is a reference voltage; and wherein the reference differential transistor pair are matched in width to length ratios to the input differential transistor pair.