Patent ID: 8138822
Filing Date: 2012-03-20
Classification: G05F,H03M

Abstract:
1. A circuit comprising: a first current source; a first switch having a second current source; a second switch having a third switch configured to open and close in response to a calibration signal, the third switch having a fourth switch configured to open and close in response to the calibration signal, the fourth switch having a programmable current source having an output coupled to the first current source or the second current source, wherein the calibration signal closes the third switch and the fourth switch in response to both the first switch and the second switch being open, and wherein the programmable current source is adjusted using a digital signal to reduce a difference between a first current from the first current source into the first node and a second current into the second current source out of the first node, wherein the digital signal is generated using a digital algorithm based on said difference.