Rambus Inc.
METHOD AND SYSTEM FOR BALANCING POWER-SUPPLY LOADING

Abstract:

A transmitter merges even and odd data streams to drive a serialized signal. Identical even and odd drivers take turns driving symbols from respective even and odd streams using respective pull-up transistors and pull-down transistors. Each transistor exhibits a significant source-gate capacitance that is charged when the transistor is turned onto drive the serialized signal. Charging one of these capacitances loads the power supply and thus introduces noise. Each even and odd driver includes a pre-driver that times the charging of a source-gate capacitance in the active driver to the discharge of a source-gate capacitance in the inactive driver. The discharge of the source-gate capacitance in the inactive driver counters the effect of charging the active driver, providing much of the power required by the active driver and thus reducing supply noise.