Rambus Inc., earns two more patents

United States Patent 7,164,997
Batra, et al. January 16, 2007

Bus line current calibration

Abstract
Disclosed herein is a method and system for calibrating line drive currents in systems that generate data signals by varying line drive currents and that interpret the data signals by comparing them to one or more reference voltages. The calibration includes varying the line drive current at a transmitting component. At different line drive currents, a receiver reference voltage is varied while the transmitting component transmits data to a receiving component. At each line drive current, the system records the highest and lowest receiver reference voltages at which data errors do not occur. The system then examines the recorded high and low receiver reference voltages to determine a desirable line drive current.

Inventors: Batra; Pradeep (Santa Clara, CA), Rutkowski; Rick A. (Sunnyvale, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 11/233,918
Filed: September 23, 2005

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United States Patent 7,164,292
Schmitt, et al. January 16, 2007

Reducing electrical noise during bus turnaround in signal transfer systems

Abstract
Systems and methods for reducing electrical noise generated during bus turnaround in signal transfer systems are provided. These systems include differential drivers having current sources continuously coupled to a signal bus during all operating modes of the drivers. A first transistor of the driver couples a first signal line of the bus to the driver current source and a second transistor of the driver couples a second signal line of the bus to the driver current source. Each transistor receives control signals in accordance with the operating mode of the driver. These control signals continuously and selectively couple the current source to the bus lines in a manner which provides uniform current distribution across the bus during all driver operating modes. The uniform current distribution across the bus minimizes interruptions in driver current dissipation and any effects from self-induced supply noise during signal transfers.
Inventors: Schmitt; Ralf (Mountain View, CA), Yuan; Xingchao (Palo Alto, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 10/866,157
Filed: June 12, 2004

HT FinzToRite.