Broadcom Corporation v. Emulex Corporation

732 F.3d 1325, 108 U.S.P.Q. 2d (BNA) 1513, 2013 WL 5508730, 2013 U.S. App. LEXIS 20411
CourtCourt of Appeals for the Federal Circuit
DecidedOctober 7, 2013
Docket20-1072
StatusPublished
Cited by46 cases

This text of 732 F.3d 1325 (Broadcom Corporation v. Emulex Corporation) is published on Counsel Stack Legal Research, covering Court of Appeals for the Federal Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Broadcom Corporation v. Emulex Corporation, 732 F.3d 1325, 108 U.S.P.Q. 2d (BNA) 1513, 2013 WL 5508730, 2013 U.S. App. LEXIS 20411 (Fed. Cir. 2013).

Opinion

RADER, Chief Judge.

After a trial and post-trial motions, the United States District Court for the Central District of California determined that Emulex Corporation (Emulex) infringed Broadcom Corporation’s (Broadcom) U.S. Patent No. 7,058,150 (the '150 patent). On appeal, the only issues remaining relate to the '150 patent, and the district court’s grant of a permanent injunction and modifications to that permanent injunction. Second Amended Notice of Appeal, Broadcom Corp. v. Emulex Corp., No. 2012-1309 (Fed.Cir. August 10, 2012) (No. 43). Upon review of the record, this court affirms the district court’s finding that Emulex infringed the '150 patent. Similarly, this court affirms the district court’s determination that the '150 patent would not have been obvious at the time of invention and hence invalid. Finally, because the district court properly exercised its discretion in granting a permanent injunction with a well-crafted sunset period, this court also affirms that determination.

I.

This case concerns digital communication systems with data transceivers capable of receiving multiple, analog, high-speed, serial data signals. '150 patent Abstract, col. 2 11.17-26. Once received, the analog data signal needs to be converted into a digital signal through a process called “sampling.” Sampling is the process of measuring the amplitude of the analog signal at precisely timed intervals in order to extract the data carried in the analog signal. To do so, the receiver needs a way to discern the proper rate at which to sample the analog signal and needs a means for generating a sampling signal having the appropriate frequency. In addition, when data is sent through cables over long distances, the incoming signal frequency can vary over time. To compensate for such variances, receiver circuits adjust the sampling signal to match the frequency and phase of the incoming data signal. Circuits for aligning and sampling data in this manner are known as Clock/Data Recovery (CDR) circuits.

The '150 patent discusses that communication devices with transceivers for transmitting and receiving data signals were known in the art. '150 patent col. 111. 18-25. And, integrating transceiver circuits on an integrated circuit (IC) chip to reduce size and power dissipation of the transceiver was also known in the art. '150 patent col. 111. 26-28. The circuits typically operate in accordance with timing signals, such as sampling signals, generated by oscilla *1329 tors. '150 patent col. 111. 26-41. Because there are multiple transceiver circuits on an IC chip, there are also multiple oscillators on a common IC chip. '150 patent col. 1 11. 26 — 41. However, the presence of multiple oscillators on one IC chip can cause one oscillator to deleteriously influence the operation of another oscillator. '150 patent col. 111. 37-47. Thus, the need to integrate transceiver circuits on an IC chip and the related need to reduce the number of oscillators on the IC chip were long felt by those of skill in the art. '150 patent col. 111. 42-47.

To reliably process a data signal, a receiver needs to match its operating characteristics with the characteristics of the data signal. '150 patent col. 1 11. 48-50. To do so, it was known in the art to employ a receiver that uses a sampling signal to sample the data signal at sample times to produce optimal data recovery and thus minimize errors. '150 patent col. 1 11. 48-55. Such timing control includes control of the phase and frequency of a sampling signal used to sample the received data signal. '150 patent col. 1 11. 59-61.

Sampling of high data rate signals also presented challenges. '150 patent col. 2 11. 7-9. In prior art systems, as the received data signal rate increased into the multigigabit-per-seeond range, the difficulty in effectively controlling sampling processes in the receiver correspondingly increased. '150 patent col. 111. 62-66. At lower rates, the sampling proceeds by making multiple copies of the same high-speed signal and distributing those copies to several sampling circuits operating in parallel. '150 patent col. 29 1. 65-col. 301. 6.

The '150 patent solves the problems in the prior art by using a phase interpolator to perform high speed sampling of a signal using a technique known as clock and data recovery. Specifically, the '150 patent addresses the sampling problem at high data rates by using four parallel data paths, each operating at a quarter of the rate of the incoming data signal. '150 patent col. 31 11. 10-37. Further, to solve the problems related to the presence of multiple oscillators on an IC chip, the '150 patent eliminates the need for multiple oscillators by “advantageously” using a single master oscillator “in a multiple receiver” environment on an IC chip. '150 patent col. 3 11. 22-40.

The invention thus relies on a single, master oscillator because the phase interpolator, not the oscillator, tunes the phase and frequency of the sampling signal. '150 patent col. 3 11. 22-25. Instead of changing the oscillator frequency, the '150 patent discloses adjusting the phase of the sampling signal forward or backward so that the sampling rate, i.e., the number of rising edges per unit time, matches the data rate. '150 patent col. 23 11. 15-41. For a change in phase to cause the same ultimate result as a change in frequency, the phase must be continually “rotated” at a specific rate — otherwise the sampling signal will not keep up with the desired sampling frequency. '150 patent col. 23 11. 17-55.

Claim 8, the only claim at issue, recites:

8. A COMMUNICATION DEVICE CONFIGURED TO RECEIVE MULTIPLE SERIAL DATA SIGNALS, COMPRISING:
a master timing generator adapted to generate a master timing signal; multiple receive-lanes each configured to receive an associated one of the multiple serial data signals, each receive-lane including
a phase interpolator adapted to produce a sampling signal having an interpolated phase, and a data path adapted to sample and quantize the associated serial data sig *1330 nal in accordance with the sampling signal; and
an interpolator control module coupled to each receive-lane, the interpolator control module being adapted to cause the phase interpolator in each receive-lane to rotate the interpolated phase of the sampling signal in the receive-lane at a rate corresponding to a frequency offset between the sampling signal and the serial data signal associated with the receive-lane so as to reduce the frequency offset between the sampling signal and the serial data signal.

'150 patent col. 38 1. 53-col. 39 1. 5.

Thus, claim 8 recites a communication device with “multiple receive-lanes each configured to receive an associated one of the multiple serial data signals.” '150 patent claim 8. Each receiving lane has a data path — a path for the analog signal to move through the circuit so that it may be sampled and turned into digital data — and a phase interpolator to adjust the sampling signal to match the incoming data in the data path. '150 patent claim 8. Claim 8 also recites an interpolator control module (ICM) — a mechanism that varies outputs of the phase interpolators in order to achieve the desired rate of phase rotation. '150 patent claim 8.

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Bluebook (online)
732 F.3d 1325, 108 U.S.P.Q. 2d (BNA) 1513, 2013 WL 5508730, 2013 U.S. App. LEXIS 20411, Counsel Stack Legal Research, https://law.counselstack.com/opinion/broadcom-corporation-v-emulex-corporation-cafc-2013.