Tuesday, May 08, 2007

Rambus Inc. lands two more patents

United States Patent 7,216,187
Perego, et al. May 8, 2007

Memory system including a circuit to convert between parallel and serial bits

A memory controller comprises a circuit to convert a set of parallel constituent bits to a serial stream of constituent bits. A first output driver receives at least four bits of the serial stream of constituent bits in succession from the circuit. The first output driver outputs the at least four bits of the serial stream of constituent bits onto a first external signal line.

Inventors: Perego; Richard E. (San Jose, CA), Ware; Fredrick A. (Los Altos Hills, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 11/151,792
Filed: June 14, 2005

United States Patent 7,215,161
Nguyen May 8, 2007

Wave shaping output driver to adjust slew rate and/or pre-emphasis of an output signal

Integrated circuit, system, method and machine readable media embodiments adjust a slew rate and/or a transmit pre-emphasis of an output signal at selected phases during a bit time. A timing circuit provides a plurality of delayed data signals in response to a clock signal. A plurality of adjustable impedance circuits, including a plurality of select circuits, output a plurality of selected delayed data signals to form the output signal having an adjusted slew rate. Delay elements in the timing circuit are also biased from a current of a lock loop circuit to further adjust slew rate of the output signal. Transmit pre-emphasis of the output signal is adjusted by selecting a polarity of a selected delayed data signal in each of the plurality of adjustable impedance circuits. Each adjustable impedance circuit also includes a predriver and driver for adjusting impedance in response to a signal indicating an impedance value. In an embodiment, an integrated circuit is able to operate in multiple modes of operation depending upon the type of output signal, frequency range of the output signal, physical packaging and/or system configuration.

Inventors: Nguyen; Huy (San Jose, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 11/068,116
Filed: February 28, 2005

HT FinzToRite.

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