02 Micro Intern. Ltd. v. Monolithic Power Systems

• Decision Date: 15 November 2006
• Docket Number: No. 06-1064.,06-1064.
• Citation: 467 F.3d 1355
• Parties: 02 MICRO INTERNATIONAL LIMITED, Plaintiff/Counterclaim Defendant-Appellant, and 02 Micro, Inc., Counterclaim Defendant-Appellant, v. MONOLITHIC POWER SYSTEMS, INC., Defendant/Counterclaimant-Appellee.
• Court: U.S. Court of Appeals — Federal Circuit

Page 1355

467 F.3d 1355

02 MICRO INTERNATIONAL LIMITED, Plaintiff/Counterclaim Defendant-Appellant, and 02 Micro, Inc., Counterclaim Defendant-Appellant, v. MONOLITHIC POWER SYSTEMS, INC., Defendant/Counterclaimant-Appellee.

No. 06-1064.

United States Court of Appeals, Federal Circuit.

November 15, 2006.

Richard L. Stanley Howrey, LLP, of Houston, Texas, argued for plaintiff/counterclaim defendant-appellant and counterclaim defendant-appellant. With him on the brief were Korula T. Cherian and Duane H. Mathiowetz, of San Francisco, California. Of counsel on the brief were Joseph Lin, O2 Micro, Inc., of Santa Clara, California; Charlene M. Morrow, Fenwick & West, LLP, of Mountain View, California; and Michael J. Sacksteder and Heather N. Mewes, Fenwick & West, LLP, of San Francisco, California. Of counsel was C.J. Alice Chen, Fenwick & West, LLP, of Mountain View, California.

Dan L. Bagatell, Perkins Coie Brown & Bain P.A., of Phoenix, Arizona, argued for defendant/counterclaimant-appellee. With him on the brief were James A. DiBoise and Michael Barclay, Wilson Sonsini Goodrich & Rosati, of Palo Alto, California.

Before MICHEL, Chief Judge, DYK and PROST, Circuit Judges.

DYK, Circuit Judge.

Appellants 02 Micro International Limited and 02 Micro, Inc. (collectively "02 Micro") appeal the district court's grant of summary judgment of non-infringement in favor of appellee Monolithic Power Systems, Inc. ("MPS"). Specifically, 02 Micro contends that the district court erred in denying it leave to amend its infringement contentions and refusing to allow supplementation of its expert report. Because we find no error in the district court's denial of leave to amend the infringement contentions, refusal to allow amendment of the expert report, or grant of summary judgment, we affirm.

BACKGROUND

I

02 Micro is the holder of U.S. Patent No. 6,259,615 ("'615 patent"), which discloses a circuit for converting direct current ("DC") to alternating current ("AC"). The principal use of the circuit is to convert the direct current supplied by laptop batteries into the alternating current required for the cold cathode fluorescent lamps ("CCFLs") that provide the lighting for computer monitors. By using feedback signals and pulse signals, the circuit controls two pairs of switches so as to regulate the amount of power delivered to the lamp.

Claim 1 of the '615 patent discloses, in relevant part, "a feedback control loop circuit receiving a feedback signal indicative of power being supplied to said [lamp], and adapted to generate a second signal [sic] pulse signal for controlling the conduction state of said second plurality of switches only if said feedback signal is above a predetermined threshold." col.10, l.67-col.11, l.5 (emphasis added).¹ The latter claim limitation requires that the second set of switches be controlled only if the feedback signal is above a certain thresh-old. Claim 18 of the '615 patent discloses a nearly identical limitation;² the parties refer to the relevant limitations in claims 1 and 18 collectively as the "only if" limitation.

II

02 Micro filed suit in the U.S. District Court for the Northern District of California on October 24, 2001, alleging infringement by MPS of claims 1 and 18 of the '615 patent. MPS counterclaimed for a declaratory judgment that the '615 patent was invalid, unenforceable, or not infringed; it also counterclaimed that 02 Micro infringed MPS's U.S. Patent No. 6,316,881 ('881 patent). (The '881 patent is no longer at issue in the appeal.) Although the complaint did not set forth a specific theory of infringement of the '615 patent, 02 Micro relied on three theories in the course of the proceedings before the district court to explain how the "only if" limitation was satisfied by the accused device. As the district court noted, "[i]n order to determine whether a device infringes the `only if' limitation, one must compare the feedback signal to the threshold in the allegedly infringing devices." 02 Micro Int'l Ltd. v. Monolithic Power Sys., Inc., Nos. C 00-4071 CW, C 01-3995 CW, slip. op. at 8 (N.D.Cal. Feb. 11, 2004).

Under 02 Micro's "Isense" theory, a feedback control loop in the accused device runs between the lamp and Isense pin. The Isense pin measures the current supplied to the lamp in terms of voltage. According to this theory, the "only if" limitation is satisfied because the second set of switches is not controlled unless the voltage measurement at the Isense pin is greater than a predetermined threshold determined by another pin, called the Bright pin.

In 02 Micro's "open lamp" theory, the feedback control loop runs between the lamp and the open lamp pin, which is designed to recognize a fault at the lamp ("open lamp condition"), such as an unattached or burnt out lamp. An open lamp condition causes the voltage at the open lamp pin to fall below a certain level, normally 1.2V, which causes all of the switches to stop. The "only if" limitation is met under this theory because the second set of switches (like all switches) is only controlled when the open lamp pin value is above the threshold of an open lamp condition (i.e., normally 1.2V).

Finally, 02 Micro's "Vsense" theory identifies the same feedback control loop as the Isense theory. During normal operations, the voltage value at the Isense pin is greater than either 92mV (standard operation), 83mV (minimum operation), or 101 mV (maximum operation). According to this theory, the second set of switches (like all switches) is only controlled during normal operations, which means that the value at the Isense pin must be above the threshold for normal operations, thus satisfying the "only if" limitation.

On May 31, 2002, the court entered a scheduling order setting the case management schedule.³ It established a period for discovery with fact discovery ending on November 4, 2002, and expert discovery ending on December 11, 2002. The scheduling order also noted the prior April 19 submission of preliminary infringement contentions and set a June 7 deadline for preliminary invalidity contentions. Finally, the court set a trial date of May 5, 2003. This order was revised on October 7, 2002. In the revised order, the court established deadlines dependent on the service of its claim construction ruling. Final infringement contentions were to be exchanged 20 days after service of the claim construction ruling. Final invalidity contentions were due 20 days later. Under this revised schedule, fact discovery was to be completed by April 21, 2003, and expert discovery by June 3. On April 21, at the joint request of the parties, the court extended fact discovery until May 9 and expert discovery until June 30.

The Northern District of California has adopted local rules that require parties to state early in the litigation and with specificity their contentions with respect to infringement and invalidity.⁴ The ability of parties to amend those contentions is restricted. Apart from amendments designed to take account of the district court's claim construction, amendments are permitted only for "good cause" even though the period allowed for discovery typically will not have expired.

02 Micro filed preliminary infringement contentions as to the '615 patent on April 19, 2002, as required by the local rules, and relied exclusively on the Isense theory. MPS' preliminary invalidity contentions as to the '615 patent were then served on June 7, 2002. The district court held a claim construction hearing on October 4, 2002, and issued its ruling on December 27, 2002. Under Patent Local Rule 3-6(a),⁵ 02 Micro had 30 days after this claim construction ruling to amend its infringement contentions without leave of the court. On January 16, 2003, 02 Micro served its final infringement contentions, still relying solely on the Isense theory. Final invalidity contentions were submitted by MPS twenty days later. Discovery was on-going during this time period, and 02 Micro deposed James C. Moyer, MPS's chief integrated circuit engineer, on February 24-25, 2003. 02 Micro contends that it was only after Dr. Moyer explained the operation of the open lamp pin that it was able to develop the open lamp theory, though 02 Micro did have documents identifying the open lamp pin as early as March 2002.

On March 17, 2003, 02 Micro requested that MPS stipulate to amendment of 02 Micro's invalidity contentions relating to the two MPS patents that are not in issue in this appeal. MPS responded on March 20, 2003, by suggesting reciprocal stipulations allowing amendments of both infringement and invalidity contentions for all patents in the case at the close of discovery. On April 7, 2003, 02 Micro indicated its willingness to enter such an agreement, provided that the amendments did not involve new statutory bases for invalidity or new prior art references.⁶ In an April 11 letter MPS responded that it "[could] not agree" to this proposal because "[t]he changes to the stipulation proposed by 02 defeats [sic] the purpose of the amendment," though MPS did indicate its willingness to continue negotiations. J.A. at 961. 02 Micro responded on April 15 with substantially the same proposal that it made on April 7, and no further negotiations took place. As the May 9, 2003, discovery deadline approached, 02 Micro counsel telephoned MPS counsel to schedule a date to exchange amended contentions. MPS responded by letter on May 14, stating that it had no plans to amend either its infringement or invalidity contentions and therefore would not stipulate to amendments; MPS did, however, agree to allow amendment of 02 Micro's invalidity contentions with respect to MPS' patents.

Undeterred, 02 Micro sent proposed supplemental infringement contentions concerning the '615 patent, which included the open lamp theory, to MPS on May 23, 2003. MPS responded that same day objecting to 02 Micro's "entirely new infringement theories" and stating that amendment of 02 Micro's...