SERDES VOLTAGE-MODE DRIVER WITH SKEW CORRECTION

摘要

A driver circuit for transmitting serial data on a communication link combines voltage-mode and current-mode drivers. The driver circuit uses a voltage-mode driver as the main output driver. One or more auxiliary current-mode drivers are connected in parallel with the voltage-mode driver to adjust the output signal by injecting currents into the outputs. The voltage-mode driver supplies most of the output drive. Thus, the output driver circuit can provide the power efficiency benefits associated with voltage-mode drivers. The current-mode drivers can provide, for example, pre-emphasis, level adjustment, skew compensation, and other modifications of the output signals. Thus, the driver circuit can also provide the signal adjustment abilities associated with current-mode drivers.

主权项

1. A driver circuit for driving data values on a differential output including a positive output node and a negative output node, the driver circuit comprising:
a voltage-mode driver module configured to drive voltages on the positive output node and the negative output node based on values on an input of the voltage-mode driver module; and a first current-mode driver module including:
a head current source operable to source a first current;a tail current source operable to sink a second current; andswitches configured to selectively couple the head current source and the tail current source to the positive output node and the negative output node based on values on an input of the first current-mode driver module, wherein the magnitudes of the first current and the second current are independently selectable.