DCT

2:23-cv-00323

Vicor Corp v. Delta Electronics Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:23-cv-00323, E.D. Tex., 07/12/2023
  • Venue Allegations: Venue is alleged to be proper for U.S.-based defendants based on their having regular and established places of business within the Eastern District of Texas. For foreign-domiciled defendants, venue is alleged to be proper in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendants’ DC-DC power converter modules, and products containing them, infringe four U.S. patents related to power converter control, architecture, and thermal management.
  • Technical Context: The technology at issue is high-efficiency, high-density DC-DC power conversion, a critical component in power-intensive applications such as datacenters, servers, and high-performance computing systems.
  • Key Procedural History: The complaint alleges that U.S. Patent No. 6,930,893 expired in 2022 but remains enforceable for past damages. It further alleges that products practicing this patent were conspicuously marked, which may be relevant to claims of pre-suit knowledge and willful infringement.

Case Timeline

Date Event
2002-01-31 U.S. Patent No. 6,930,893 Priority Date
2005-08-16 U.S. Patent No. 6,930,893 Issued
2011-05-11 U.S. Patent No. 9,516,761 Priority Date
2013-03-14 U.S. Patent No. 9,166,481 Priority Date
2013-07-02 U.S. Patent No. 10,199,950 Priority Date
2015-10-20 U.S. Patent No. 9,166,481 Issued
2016-12-06 U.S. Patent No. 9,516,761 Issued
2019-02-05 U.S. Patent No. 10,199,950 Issued
2021-05-28 Accused Product Series Announced
2023-07-12 Complaint Filed

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

U.S. Patent No. 9,166,481 - "Digital Control of Resonant Power Converters"

The Invention Explained

  • Problem Addressed: The patent addresses the need for precise digital control of Sine Amplitude Converters ("SACs"), a type of power converter designed for high efficiency and high power density, to minimize power loss during the switching of electronic components (Compl. ¶53).
  • The Patented Solution: The invention is a method that uses digitally generated timing signals, based on a fixed-frequency oscillator, to turn power switches ON and OFF at moments of "essentially zero voltage and zero current" (Compl. ¶53). A key aspect is that the timing for various switching events can be set independently of one another, allowing for fine-tuned digital control (Compl. ¶67). The patent's Figure 2, referenced in the complaint, depicts a "Digital SAC Controller" block diagram that illustrates the components for implementing this method (Compl. p. 27).
  • Technical Importance: This digital control method enables the development of high-density and high-efficiency power converters, which are critical components for demanding applications such as modern datacenters (Compl. ¶53).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶65).
  • The essential elements of claim 1 are:
    • A method of synchronously operating a power converter with at least one primary switch and at least one secondary switch driving a resonant power train including a transformer.
    • Providing an oscillator to generate clock signals.
    • Generating timing control signals from the clock signals to turn the primary switch ON and OFF at times of essentially zero voltage and essentially zero resonant current.
    • Generating timing control signals to turn the secondary switch ON and OFF at times of essentially zero current and essentially zero voltage.
    • The oscillator frequency is preset, and the timing of control signals for selected events can be set independently of other signals.
  • The complaint states infringement of "at least claim 1," thereby reserving the right to assert additional claims (Compl. ¶65).

U.S. Patent No. 9,516,761 - "Encapsulated Modular Power Converter with Symmetric Heat Distribution"

The Invention Explained

  • Problem Addressed: The patent addresses the technical challenge of managing heat density in compact power converters, as excessive heat can limit both power density and operational efficiency (Compl. ¶55).
  • The Patented Solution: The invention claims a power converter architecture that distributes heat through both the top and bottom surfaces of the device. This is achieved by mounting power semiconductor devices on both the top and bottom surfaces of a printed circuit board (PCB) and arranging them in a "symmetrical multi-cell converter topology" that shares conductive vias through the PCB, thereby balancing the thermal load (Compl. ¶55). The complaint includes Figure 27 from the patent, which illustrates this top and bottom component layout (Compl. p. 28).
  • Technical Importance: This symmetric thermal design reduces localized heat density, which in turn improves both the efficiency and the achievable power density of the converter module (Compl. ¶55).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶111).
  • The essential elements of claim 1 are:
    • An apparatus comprising a power converter with a PCB having top and bottom surfaces and a magnetic core structure.
    • A first set of power semiconductor devices mounted on the top surface, dissipating power at a level Pt.
    • A second set of power semiconductor devices mounted on the bottom surface, dissipating power at a level Pb.
    • The devices are distributed between the top and bottom sets to manage heat such that the power dissipated on one surface (Pt or Pb) is less than 150% of the power dissipated on the other.
  • The complaint asserts infringement of "at least claim 1," reserving the right to assert others (Compl. ¶111).

U.S. Patent No. 10,199,950 - "Power Distribution Architecture with Series-Connected Bus Converter"

  • Patent Identification: 10,199,950, "Power Distribution Architecture with Series-Connected Bus Converter," issued February 5, 2019 (Compl. ¶56).
  • Technology Synopsis: The patent claims a power distribution architecture using a class of non-isolated, fixed-ratio Sine Amplitude Converter modules. This "series-connected" configuration is described as enabling more efficient power distribution and superior power system density, particularly for applications with extreme power requirements like high-performance computing (Compl. ¶57).
  • Asserted Claims: Independent claim 9 (Compl. ¶154).
  • Accused Features: The Delta U50SU Series power modules are accused of infringing by being configured as a power converter with an input and output circuit connected in series across a power source (Compl. ¶¶155, 160).

U.S. Patent No. 6,930,893 - "Factorized Power Architecture With Point of Load Sine Amplitude Converters"

  • Patent Identification: 6,930,893, "Factorized Power Architecture With Point of Load Sine Amplitude Converters," issued August 16, 2005 (Compl. ¶58).
  • Technology Synopsis: The patent claims a fixed-ratio Sine Amplitude Converter where the conversion frequency is "locked" to the resonance of a "low Q" resonant circuit. This approach is alleged to enable greater power converter density and efficiency for distributed power systems in applications such as datacenters (Compl. ¶59).
  • Asserted Claims: Independent claim 1 (Compl. ¶200).
  • Accused Features: The Delta U50SU Series power modules are accused of infringing by allegedly practicing a method of power conversion that uses a resonant circuit with a Q less than 13 and achieves a peak conversion efficiency greater than 90% (Compl. ¶¶201, 205, 206).

III. The Accused Instrumentality

Product Identification

  • The primary accused products are the "Delta U50SU Series High Power Density 48V / 12V Bi-Directional DC-DC Converter Power Module," including models U50SU4P162, U50SU4P162MAR, and U50SU4P162PMDRF (Compl. ¶62). The complaint also accuses broader "power systems and/or products containing the same (e.g., power distribution networks ('PDNs'), servers, and AI accelerators)" that are manufactured and sold by all defendants (Compl. ¶62, ¶81, ¶96).

Functionality and Market Context

  • The accused modules are described as "highly efficient and reliable power supply" components "packed into a compact form factor" (Compl. ¶68). A product datasheet included in the complaint shows the U50SU4P162 module is designed to convert a high-side input voltage of 38-60V to a low-side voltage of 9.5V-15V (Compl. p. 34). These modules are alleged to be requirements for datacenters, supercomputers, and other high-end equipment (Compl. ¶68). The complaint alleges that defendants Foxconn and Quanta incorporate these or similar infringing modules into the servers and power systems they sell (Compl. ¶¶81, 96).

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,166,481 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of synchronously operating a power converter... the converter having at least one primary switch to drive a resonant power train and at least one secondary switch, the resonant power train including a transformer and having a characteristic resonant frequency and period... The accused module is a power converter that allegedly comprises at least one primary switch, a resonant power train with a transformer, and at least one secondary switch. ¶70 col. 1:49-54
providing an oscillator for generating clock signals at an oscillator frequency; The accused module allegedly contains an oscillator that generates clock signals at a specified frequency. ¶70 col. 6:29-31
generating timing control signals for each of a plurality of events based upon the clock signals... to: (i) turn the at least one primary switch ON and OFF at times when essentially zero voltage is impressed... and essentially zero resonant current is flowing... and (ii) turn the at least one secondary switch ON and OFF at times when essentially zero current is flowing... and essentially zero voltage is impressed... The accused module allegedly generates timing signals to control its primary and secondary switches to turn ON and OFF at times when voltage and current are "essentially zero." ¶71 col. 2:25-31
wherein the oscillator frequency is preset, and the timing of the timing control signals for one or more selected events may be set independently of other timing control signals and events. The accused module allegedly operates with a preset oscillator frequency, and the timing of its control signals for different events can be set independently of one another. ¶71 col. 7:42-47

Identified Points of Contention

  • Scope Questions: The infringement analysis may focus on the scope of terms of degree, such as "essentially zero voltage" and "essentially zero resonant current." A central question will be what degree of deviation from absolute zero falls within the scope of this language.
  • Technical Questions: The complaint's allegations regarding the performance of the claimed method are based on product datasheets and press releases (Compl. pp. 33, 34). A key question for the court will be what technical evidence, such as oscilloscope measurements or circuit simulations, demonstrates that the accused modules actually perform the switching steps at the precise moments of "essentially zero" voltage and current as required by the claim.

U.S. Patent No. 9,516,761 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An apparatus comprising: a power converter including a printed circuit board (PCB) comprising a plurality of conductive layers and having a top surface and a bottom surface; a magnetic core structure magnetically coupled to a winding formed by traces in one or more of the conductive layers in the PCB... The accused module is alleged to be a power converter built on a multi-layer PCB with a magnetic core structure coupled to windings formed by traces within the PCB layers. ¶116 col. 11:1-4
and a plurality of power semiconductor devices, a first set of the power semiconductor devices being mounted on the top surface... a second set of the power semiconductor devices being mounted on the bottom surface... The accused module allegedly has power semiconductor devices mounted on both its top and bottom surfaces. A teardown image is provided as evidence of this structure (Compl. p. 55). ¶117 col. 2:54-60
wherein the power semiconductor devices are distributed between the first and second sets to distribute heat generation during operation of the converter such that each level Pt, Pb is less than 150% of the other level Pb, Pt. The complaint alleges that the distribution of semiconductor devices between the top and bottom surfaces results in a thermal power dissipation ratio where neither side exceeds the other by 150%. ¶117 col. 24:1-12

Identified Points of Contention

  • Technical Questions: The complaint's primary evidence for the physical structure is a teardown photograph showing components on both sides of the PCB (Compl. p. 55). However, the central technical question will be whether the accused module meets the functional limitation regarding heat distribution. The complaint alleges this "less than 150%" ratio is met (Compl. ¶117), but provides no thermal analysis, test data, or simulation results to substantiate this functional claim.

V. Key Claim Terms for Construction

For the ’481 Patent

  • The Term: "essentially zero voltage" and "essentially zero resonant current"
  • Context and Importance: These terms define the "soft switching" conditions (ZVS/ZCS) that are critical to the patent's claimed efficiency improvements. The infringement analysis will depend heavily on whether the accused device's operation, which may deviate from a theoretical ideal, still falls within the scope of "essentially zero." Practitioners may focus on this term because it is a term of degree that is open to interpretation and will likely require expert testimony to define its bounds in the context of the patent.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The use of the modifier "essentially" suggests the patentee did not intend to require an absolute zero value, but rather a value close enough to zero to achieve the technical benefits of reduced power loss described in the patent (Compl. ¶53).
    • Evidence for a Narrower Interpretation: The patent's focus on "digital control" and a "Digital SAC Controller" (Compl. p. 27) could suggest that a high degree of precision is intended, supporting a construction where "essentially zero" means a value very close to absolute zero, rather than a broad approximation.

For the ’761 Patent

  • The Term: "distribute heat generation ... such that each level Pt, Pb is less than 150% of the other level Pb, Pt"
  • Context and Importance: This quantitative functional limitation is the core of the asserted claim. Infringement requires not just a particular structure (components on both sides) but achieving a specific performance metric for thermal balance. The case may turn on how Pt (power dissipated by the top set) and Pb (power dissipated by the bottom set) are measured and whether the accused product meets this ratio.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent's title refers to "Symmetric Heat Distribution," and the specification describes using "symmetrical multi-cell converter topologies" (Compl. ¶¶54, 55). This focus on symmetry could support an interpretation where the 150% threshold is an exemplary embodiment of achieving a balanced, symmetrical design.
    • Evidence for a Narrower Interpretation: The claim recites a specific, objective numerical threshold ("less than 150%"). This explicit numerical limit could support a narrower construction where any device operating outside this ratio, regardless of its structural symmetry, does not infringe.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. Inducement is primarily based on allegations that Defendants provide "marketing, user manuals, and online instruction materials" as well as "Application Notes" that instruct customers on how to use the accused products in an infringing manner (Compl. ¶¶75-76, 90-91, 105-106). Contributory infringement is based on allegations that the accused modules contain a material part of the inventions, are not staple articles of commerce, and are especially made for an infringing use (Compl. ¶¶77, 92, 107).
  • Willful Infringement: The complaint alleges willful infringement against all defendants for all asserted patents. For most patents, willfulness is based on knowledge acquired "no later than the filing and service of the Complaint" (e.g., Compl. ¶75). However, the complaint also makes stronger allegations of deliberate copying of the "design, layout, and functions of the Vicor products" (Compl. ¶¶78, 93, 108). For the ’893 Patent specifically, it alleges pre-suit knowledge based on Defendants' alleged copying of Vicor products that were "conspicuously marked with the ’893 Patent" (Compl. ¶213).

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

  • A central issue will be one of evidentiary proof for functional claims: The asserted claims contain key limitations defined by performance (e.g., "essentially zero voltage" switching, a heat dissipation ratio "less than 150%", and efficiency "greater than 90%"). A primary focus of the litigation will likely be on the technical evidence—such as testing, thermal imaging, and circuit analysis—required to prove whether the accused products actually operate in a manner that meets these specific, quantitative performance thresholds.
  • A second core issue will be one of intent and origin: The complaint repeatedly alleges not just infringement, but that Defendants "deliberately copied" Vicor's patented technology, particularly with respect to products allegedly marked with the '893 patent number. This elevates the dispute beyond a typical infringement question and raises a key question for the court regarding evidence of independent development versus copying, which will be central to the claims for willful infringement.