Patent ID: 7902883
Filing Date: 2011-03-08
Classification: H04L

Abstract:
1. A system comprising: a low-frequency-period replica driver that comprises a plurality of n-type digital-to-analog converter (NDAC) current sources, the replica driver being operable to produce a low-frequency-period reference voltage based on current supplied by the NDAC current sources, wherein the replica driver further comprises a plurality of switches that are operable to selectively couple one of the NDAC current sources to a low-output voltage (VOL) node or a high-output voltage (VOH) node of the replica driver; a peak-output-voltage replica driver that comprises another plurality of NDAC current sources, the peak-output-voltage replica driver being operable to produce a peak-output-voltage reference voltage based on current supplied by the other NDAC current sources; and a plurality of driver fingers that are coupled to the replica driver and each comprise a driver bias circuit and an output driver, the driver bias circuit comprising an operational amplifier (op-amp) that is operable to adjust current-source gate voltage in the output driver to produce voltages at output nodes of the driver fingers that approximately match the reference voltage produced by the replica driver, each one of the driver bias circuits comprising a switch that is operable to selectively couple an input of the op-amp in the driver bias circuit to the low-frequency-period reference voltage or the peak-output-voltage reference voltage.