SynQor Inc v. Vicor Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: SynQor, Inc. (Delaware)
  • Defendant: Cisco Systems, Inc. (California) and Vicor Corporation (Delaware)
  • Plaintiff’s Counsel: Sidley Austin LLP
• Case Identification: 2:11-cv-00054, E.D. Tex., 09/20/2011
• Venue Allegations: Plaintiff alleges venue is proper because Defendants conduct continuous business in the district, and because the current case is directly related to a prior patent infringement action in the same court (the "'497 case") involving the same patents and some of the same products, promoting judicial efficiency.
• Core Dispute: Plaintiff alleges that Defendant Vicor’s DC/DC bus converters, and Defendant Cisco’s telecommunications and computer products that incorporate them, infringe a portfolio of patents related to high-efficiency power conversion technology.
• Technical Context: The technology at issue involves DC/DC power converters used in intermediate bus architecture (IBA), a common design for efficiently distributing power at different voltage levels within modern electronic systems like servers and routers.
• Key Procedural History: The complaint heavily relies on prior litigation, SynQor, Inc. v. Artesyn Technologies, Inc. et al. (the "'497 case"), where a jury found five of the patents-in-suit infringed by other manufacturers' bus converters. The complaint asserts that the jury in that case, by awarding lost profits, necessarily found that Vicor's bus converters (which were presented as non-infringing alternatives) would also infringe the patents. An injunction was issued in the '497 case against the defendants and their customers, including Cisco, which allegedly prompted Cisco to replace the enjoined components with the accused Vicor converters.

Case Timeline

Date	Event
1997-01-24	Earliest Priority Date for ’190, ’034, ’083, ’702, ’290 Patents
2002-12-06	Earliest Priority Date for ’021 Patent
2006-07-04	U.S. Patent No. 7,072,190 Issues
2007-09-11	U.S. Patent No. 7,269,034 Issues
2007-09-18	U.S. Patent No. 7,272,021 Issues
2007-11-13	’497 case filed against other defendants
2009-06-01	Complaint alleges Cisco had notice of patents by this time (Summer 2009)
2009-07-07	U.S. Patent No. 7,558,083 Issues
2009-07-21	U.S. Patent No. 7,564,702 Issues
2010-07-27	Complaint alleges Vicor had notice of patents
2010-12-21	Jury verdict in ’497 case
2011-01-28	Original complaint filed in this action
2011-09-20	U.S. Patent No. 8,023,290 Issues
2011-09-20	First Amended Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,072,190 - "High Efficiency Power Converter"

The Invention Explained

• Problem Addressed: The patent addresses the technical challenge of creating high-efficiency switching power converters, particularly those used for low-voltage applications. A significant source of energy loss in conventional converters is the conduction loss in diodes used for rectification, and additional losses occur during the switching transitions of transistors (’190 Patent, col. 1:36-62).
• The Patented Solution: The invention proposes a power converter topology that uses transistors as "synchronous rectifiers" to reduce conduction losses and a specific circuit architecture and control method to minimize losses during switching transitions. The system uses a two-stage approach: a regulation stage followed by a non-regulating isolation stage with a fixed duty cycle, where energy from parasitic capacitances and inductances is "nearly losslessly delivered to and recovered" during switching transitions (’190 Patent, col. 2:5-18, 51-64; Fig. 1).
• Technical Importance: This approach allows for higher switching frequencies, which enables smaller physical components, without the typical efficiency penalty, a critical factor for compact electronic devices (’190 Patent, col. 1:26-35).

Key Claims at a Glance

• The complaint does not explicitly assert specific claims, but references those found to be infringed in the prior '497 case (Compl. ¶19). The lead independent claim of the ’190 Patent is Claim 1.
• Claim 1 of the ’190 Patent includes these essential elements:
  • A DC power source.
  • A non-regulating isolation stage comprising a primary transformer winding circuit and a secondary transformer winding circuit.
  • The secondary circuit has plural controlled rectifiers, each with a parallel uncontrolled rectifier.
  • The controlled rectifiers are turned on and off in synchronization with the voltage waveform across the primary winding.
  • Each primary winding has a voltage waveform with a fixed duty cycle and short transition times relative to the on-state and off-state times of the controlled rectifiers.
  • A plurality of non-isolating regulation stages that receive the output of the isolation stage and regulate it.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 7,272,021 - "Power Converter with Isolated and Regulated Stages"

The Invention Explained

• Problem Addressed: This patent addresses similar efficiency challenges as the '190 Patent but focuses on system architecture and control during both normal and abnormal conditions, such as startup or short-circuits (’021 Patent, col. 2:20-24). Conventional converters may be inefficient or unstable during these non-standard operating modes.
• The Patented Solution: The invention describes a power converter system with a "normally non-regulating isolation stage" followed by one or more regulation stages. The key is a control circuit that maintains a duty cycle causing "substantially uninterrupted control of power" during normal operation but can reduce the duty cycle to create "freewheeling periods" during other conditions like startup or to limit current (’021 Patent, col. 2:5-19). This allows the converter to be highly efficient in its normal mode while remaining stable and safe in other modes.
• Technical Importance: This architecture provides a robust and efficient power distribution system, known as Intermediate Bus Architecture (IBA), suitable for complex electronics that require multiple regulated downstream voltages (’021 Patent, Fig. 5).

Key Claims at a Glance

• The complaint references claims 21 and 30 as having been found infringed in the '497 case (Compl. ¶19). Claim 21 is an independent claim.
• Claim 21 of the ’021 Patent includes these essential elements:
  • A normally non-regulating isolation stage comprising a primary winding circuit and a secondary winding circuit.
  • The secondary circuit includes a controlled rectifier with a parallel uncontrolled rectifier.
  • A control circuit that controls the duty cycle of the primary winding circuit.
  • The duty cycle causes "substantially uninterrupted flow of power" during normal operation.
  • A plurality of non-isolating regulation stages receiving the output from the isolation stage.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 7,269,034 - "High Efficiency Power Converter"

• Technology Synopsis: This patent is part of the same family as the '190 Patent and describes a similar two-stage power converter architecture. It further details the control of the isolation/semi-regulation stage and its interaction with plural downstream non-isolating regulators to provide multiple regulated voltage outputs from a single semi-regulated bus voltage (’034 Patent, Abstract; col. 2:48-62).
• Asserted Claims: The complaint references claim 9 as having been found infringed in the '497 case (Compl. ¶19.a).
• Accused Features: The complaint accuses Cisco’s products incorporating semi-regulated bus converters with point-of-load converters (POLs) in an intermediate bus architecture of infringing the ’034 Patent (Compl. ¶72).

U.S. Patent No. 7,558,083 - "High Efficiency Power Converter"

• Technology Synopsis: This patent is also in the same family as the '190 Patent. It describes a high-efficiency power converter topology using synchronous rectifiers whose control inputs are cross-coupled from opposite secondary transformer windings, enabling properly timed, efficient switching without complex secondary-side control circuitry (’083 Patent, Abstract; col. 2:45-54).
• Asserted Claims: The complaint references claim 1 as having been found infringed in the '497 case (Compl. ¶19.a).
• Accused Features: The complaint accuses Cisco’s products incorporating unregulated bus converters of infringing the ’083 Patent (Compl. ¶78).

U.S. Patent No. 7,564,702 - "High Efficiency Power Converter"

• Technology Synopsis: Also in the '190 Patent family, this patent details a power converter architecture where a regulation stage precedes a fixed-duty-cycle isolation stage. The claims focus on the combination of a regulation stage, a non-regulating isolation stage with specific rectifier configurations, and the resulting regulated output voltage (’702 Patent, Abstract; Claim 1).
• Asserted Claims: The complaint references claims 56 and 71 as having been found infringed in the '497 case (Compl. ¶19.a).
• Accused Features: The complaint accuses Vicor's unregulated bus converters and Cisco's products incorporating them of infringing the ’702 Patent (Compl. ¶48, ¶84).

U.S. Patent No. 8,023,290 - "High Efficiency Power Converter"

• Technology Synopsis: This patent, also part of the same family, describes a similar high-efficiency DC-DC converter. It claims a system architecture comprising a non-regulating isolation stage that provides a semi-regulated output, followed by a plurality of non-isolating switching regulators that receive this output to provide multiple, fully regulated DC outputs (’290 Patent, Abstract; Claim 1).
• Asserted Claims: This patent was not part of the '497 case; the complaint does not assert specific claims (Compl. ¶18, ¶54, ¶90).
• Accused Features: The complaint accuses Vicor's unregulated bus converters and Cisco's products incorporating them of infringing the ’290 Patent (Compl. ¶54, ¶90).

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are "unregulated bus converters and/or semi-regulated bus converters used in intermediate bus architecture power supply systems" manufactured and sold by Vicor, and products sold by Cisco that incorporate these converters (Compl. ¶2, ¶3, ¶6, ¶31).

Functionality and Market Context

• The complaint describes the accused products by their function and market category rather than by specific technical operation. They are DC/DC power converters that serve as an intermediate stage in a power distribution system, taking a higher voltage DC input and converting it to a lower, intermediate DC voltage bus. This bus then powers multiple downstream point-of-load (POL) converters that provide the final regulated voltages for electronic components (Compl. ¶2, ¶3, ¶60). The complaint alleges that Cisco intends to use the accused Vicor converters as replacements for previously used converters that were found to infringe in the '497 case (Compl. ¶31).

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint alleges infringement in conclusory terms without mapping specific product features to claim limitations. The infringement theory appears to rest heavily on the jury finding in the prior '497 case, where Vicor's converters were presented as alternatives to the adjudicated infringing products (Compl. ¶22).

U.S. Patent No. 7,072,190 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a non-regulating isolation stage comprising: a primary transformer winding circuit . . . and a secondary transformer winding circuit . . .	The complaint alleges that Vicor's unregulated and semi-regulated bus converters are or contain the claimed non-regulating isolation stage.	¶36, ¶60	col. 2:5-18
plural controlled rectifiers, each having a parallel uncontrolled rectifier . . .	The complaint does not provide sufficient detail for analysis of this element.	¶36, ¶60	col. 2:9-12
each controlled rectifier being turned on and off in synchronization with the voltage waveform across a primary winding . . .	The complaint does not provide sufficient detail for analysis of this element.	¶36, ¶60	col. 2:12-14
each primary winding having a voltage waveform with a fixed duty cycle and transition times which are short relative to the on-state and off-state times of the controlled rectifiers	The complaint alleges that Vicor's converters operate with a fixed duty cycle, a central feature of the patented technology.	¶36, ¶60	col. 2:14-18
a plurality of non-isolating regulation stages, each receiving the output of the isolation stage and regulating a regulation stage output	The complaint alleges the accused converters are used in systems with downstream POLs, which function as the claimed regulation stages.	¶60	col. 2:38-42

Identified Points of Contention

• Scope Questions: A central issue may be whether Vicor’s products, described as "unregulated" or "semi-regulated," meet the claim limitation of a "non-regulating isolation stage." The parties may dispute the degree of regulation permissible before a stage is no longer considered "non-regulating."
• Technical Questions: A key evidentiary question will be whether the accused converters operate with a "fixed duty cycle" as claimed. The defense may argue that the converters' duty cycles vary under certain load or input conditions, thereby falling outside the scope of the claim.

U.S. Patent No. 7,272,021 Infringement Allegations

Claim Element (from Independent Claim 21)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a normally non-regulating isolation stage comprising: a primary winding circuit; a secondary winding circuit . . .	The complaint alleges that Vicor's bus converters function as the claimed normally non-regulating isolation stage.	¶42, ¶66	col. 2:7-12
a control circuit which controls duty cycle of the primary winding circuit . . .	The complaint does not provide sufficient detail for analysis of this element.	¶42, ¶66	col. 2:14-15
the duty cycle causing substantially uninterrupted flow of power through the primary and secondary winding circuits during normal operation	The complaint alleges the accused converters are used in a manner that provides for this substantially uninterrupted power flow.	¶42, ¶66	col. 2:15-19
a plurality of non-isolating regulation stages, each receiving the non-regulated output of the isolation stage and regulating a regulation stage output	The complaint alleges that Cisco’s products incorporate the accused bus converters with downstream POLs, which serve as the claimed regulation stages.	¶66	col. 2:20-23

Identified Points of Contention

• Scope Questions: The term "substantially uninterrupted flow of power" will likely be a key point of contention. The defense may argue that the operation of the accused converters includes periods that interrupt the power flow to a degree that is not "substantially uninterrupted."
• Technical Questions: Analysis may focus on what constitutes "normal operation" for the accused converters. The defense could argue that the operating conditions under which power flow is uninterrupted do not represent the full range of the products' "normal operation," especially if the control circuit reduces the duty cycle under common load conditions.

V. Key Claim Terms for Construction

The Term: "non-regulating isolation stage" ('190 Patent, Claim 1)

Context and Importance

This term is fundamental to the patent's two-stage architecture, distinguishing it from conventional single-stage regulated converters. Practitioners may focus on this term because the accused products are described as "unregulated" and "semi-regulated," making the precise scope of "non-regulating" critical to the infringement analysis.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The specification distinguishes this stage from a "regulation stage" and states its output is then received by "a plurality of non-isolating regulation stages," suggesting that the "non-regulating" character is defined by its role in the overall system architecture rather than a complete absence of any voltage-stabilizing effect (’190 Patent, col. 2:38-42, Claim 1).
• Evidence for a Narrower Interpretation: The specification describes the stage as operating with a "fixed duty cycle," which implies that its output voltage will vary directly with its input voltage, a characteristic of a truly non-regulating converter (’190 Patent, col. 2:14-18).

The Term: "fixed duty cycle" ('190 Patent, Claim 1)

Context and Importance

This term is a core operational parameter of the invention that enables high efficiency. Whether the accused converters operate at a "fixed" duty cycle will be a central factual dispute.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The specification contrasts the "fixed duty cycle" with control schemes where the duty cycle is actively varied to provide regulation, stating "A regulator regulates the output while the fixed duty cycle is maintained" (’190 Patent, col. 2:16-18). This could support an interpretation where minor, incidental variations in duty cycle do not negate its "fixed" nature, so long as it is not the primary means of regulation.
• Evidence for a Narrower Interpretation: The related ’021 Patent explicitly distinguishes "normal operation" with "substantially uninterrupted... power" (implying a fixed, high duty cycle) from other conditions where the "duty cycle may be reduced" (’021 Patent, col. 2:13-22). This suggests that "fixed" implies an absence of intentional variation during normal operation.

VI. Other Allegations

Indirect Infringement

• The complaint alleges both induced and contributory infringement against Vicor and Cisco (Compl. ¶36, ¶60). It alleges Vicor and Cisco had knowledge of the patents and their likely infringement based on subpoenas, depositions, and testimony in the '497 case, as well as direct pre-suit notice (Compl. ¶32, ¶33, ¶34). For contributory infringement, it alleges the accused converters are "especially made or adapted for use in an infringement" and are not "staple articles or commodities of commerce" (Compl. ¶37).

Willful Infringement

• The complaint alleges willful and deliberate infringement based on Defendants' alleged long-standing, pre-suit notice of the patents-in-suit and SynQor's infringement allegations, stemming from the '497 litigation (Compl. ¶40, ¶46, ¶52, ¶58, ¶64, ¶70, ¶76, ¶82, ¶88, ¶94).

VII. Analyst’s Conclusion: Key Questions for the Case

• A primary issue will be one of legal preclusion: to what extent can the findings from the '497 case—particularly the jury's implicit determination that Vicor's products were not acceptable non-infringing alternatives—be used to establish infringement or knowledge in this separate action against Vicor and its customer, Cisco?
• A central evidentiary question will be one of technical operation: do the accused Vicor bus converters, described by the plaintiff as "unregulated" and "semi-regulated," actually operate with the "fixed duty cycle" of a "non-regulating isolation stage" as required by the asserted claims, or do they employ a control scheme that varies the duty cycle in a manner that places them outside the claims' scope?
• A further question will be one of system-level infringement: for claims requiring a combination of an isolation stage and separate regulation stages, what evidence will be presented to show that Cisco's final products, which incorporate the accused Vicor converters along with downstream POLs, practice all elements of the asserted system claims?