DCT
1:17-cv-00247
On Semiconductor Corp v. Power Integrations Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: ON Semiconductor Corporation and Semiconductor Components Industries, LLC (Delaware)
- Defendant: Power Integrations, Inc. (Delaware)
- Plaintiff’s Counsel: Ashby & Geddes; Baker Botts L.L.P.
- Case Identification: 1:17-cv-00247, D. Del., 03/09/2017
- Venue Allegations: Venue is alleged to be proper in the District of Delaware because the Defendant is a Delaware corporation and therefore resides in the district.
- Core Dispute: Plaintiff alleges that Defendant’s InnoSwitch family of semiconductor products, used in fast-charging power adapters, infringes six patents related to synchronous rectification and power converter technology.
- Technical Context: The lawsuit concerns integrated circuits for AC-DC power converters, a critical component in chargers for mobile devices, where high efficiency and rapid charging are significant market drivers.
- Key Procedural History: The complaint does not allege any prior litigation, licensing history, or post-grant proceedings involving the asserted patents.
Case Timeline
| Date | Event |
|---|---|
| 2003-07-01 | Earliest Priority Date for '211 Patent |
| 2006-08-11 | Earliest Priority Date for '298 and '705 Patents |
| 2006-09-05 | '211 Patent Issued |
| 2007-12-03 | Earliest Priority Date for '407 Patent |
| 2008-02-29 | Earliest Priority Date for '923 Patent |
| 2008-10-21 | '298 Patent Issued |
| 2009-07-21 | '705 Patent Issued |
| 2010-09-14 | '407 Patent Issued |
| 2010-09-21 | '923 Patent Issued |
| 2011-07-26 | Earliest Priority Date for '258 Patent |
| 2015-07-07 | '258 Patent Issued |
| 2017-03-09 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,440,298 - "Synchronous Rectification Circuit for Power Converters" (Issued Oct. 21, 2008)
The Invention Explained
- Problem Addressed: In conventional switching power converters using synchronous rectification, a "reverse current" can flow if the rectifier switch is not turned off at the precise moment the transformer is fully demagnetized, which reduces power efficiency ('298 Patent, col. 1:49-57). Existing methods to prevent this, such as current-sensing or phase-lock circuits, add complexity and power loss ('298 Patent, col. 1:65-col. 2:2).
- The Patented Solution: The invention proposes a switching-control circuit that does not directly measure current. Instead, it generates a control signal to turn the power switch on and off by calculating the required demagnetization period based on three inputs: the magnetized voltage of the transformer, the demagnetized voltage (output voltage), and the magnetization period ('298 Patent, col. 2:8-17; Fig. 4). This allows the circuit to predict the ideal turn-off point to prevent reverse current flow without the need for complex and lossy sensing components.
- Technical Importance: This predictive control method aimed to improve power converter efficiency, a key requirement for compact, fast-charging adapters, by eliminating the need for components that themselves consume power.
Key Claims at a Glance
- The complaint asserts infringement of at least independent Claim 1 (Compl. ¶22).
- Essential Elements of Claim 1:
- A power switch coupled to a transformer for rectification.
- A switching-control circuit that generates a control signal.
- The control signal is generated in response to:
- a magnetized voltage of the transformer,
- a demagnetized voltage of the transformer, and
- a magnetization period of the transformer.
- The control signal is coupled to control the power switch.
- The enable period of the control signal is correlated to a demagnetization period of the transformer.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 7,564,705 - "Synchronous Rectification Circuit for Power Converters" (Issued Jul. 21, 2009)
The Invention Explained
- Problem Addressed: This patent, a continuation of the application leading to the '298 patent, addresses the same problem of reverse current flow in synchronous rectifiers reducing efficiency ('705 Patent, col. 1:47-55).
- The Patented Solution: The '705 patent also discloses a switching-control circuit that obviates the need for current-sense or phase-lock circuits ('705 Patent, col. 2:15-18). The claimed solution is a control circuit that generates a control signal to determine the demagnetization period based on the magnetized and demagnetized voltages of a magnetic device (e.g., a transformer), thereby controlling the power switch to improve efficiency ('705 Patent, Abstract). The specification describes generating the control signal by using a capacitor that is charged and discharged based on signals correlated to the transformer's state ('705 Patent, col. 4:46-67).
- Technical Importance: Like the '298 patent, this invention provided a method to increase the efficiency of power converters, which is crucial for meeting regulatory standards and consumer demand for smaller, more powerful chargers.
Key Claims at a Glance
- The complaint asserts infringement of at least independent Claim 1 (Compl. ¶30).
- Essential Elements of Claim 1:
- A power switch coupled to a magnetic device for rectification.
- A switching-control circuit generating a control signal in response to:
- a magnetized voltage of the magnetic device, and
- a demagnetized voltage of the magnetic device.
- The control signal is coupled to control the power switch to determine a demagnetization period of the magnetic device.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 9,077,258 - "Regulation Circuit Associated with Synchronous Rectifier Providing Cable Compensation for the Power Converter and Method Thereof" (Issued July 7, 2015)
- Technology Synopsis: This patent addresses voltage drops that occur over the length of a charging cable, which can slow down charging. The invention provides a regulation circuit that uses the synchronous rectifying signal—which is correlated to the output current—to generate a compensation signal. This compensation signal adjusts the power converter's reference voltage to offset the cable voltage drop, ensuring the correct voltage is delivered to the device without needing a separate, power-consuming shunt resistor to measure the current ('258 Patent, col. 1:49-60, col. 2:2-6).
- Asserted Claims: Independent Claim 1 (Compl. ¶38).
- Accused Features: The complaint alleges the InnoSwitch family of products includes a power converter with a regulation circuit that has a signal generator and an error amplifier arranged in an infringing manner (Compl. ¶38).
U.S. Patent No. 7,796,407 - "Method and Apparatus for Providing Synchronous Regulation for Offline Power Converter" (Issued Sept. 14, 2010)
- Technology Synopsis: This patent describes an integrated regulation circuit for an offline power converter that combines primary-side control and secondary-side synchronous rectification. An isolation device (e.g., capacitor or pulse transformer) transfers a synchronous signal from the secondary side to the primary side. This signal is used on the primary side to generate switching signals for soft switching, while a pulse signal on the secondary side controls a synchronous rectifier, aiming to achieve high efficiency from no-load to full-load conditions ('407 Patent, col. 1:44-54).
- Asserted Claims: Independent Claim 1 (Compl. ¶46).
- Accused Features: The complaint alleges the InnoSwitch family of products constitutes an infringing synchronous regulation power converter that includes a secondary side switching circuit, an isolation device, a primary side switching circuit, and a synchronous switch (Compl. ¶46).
U.S. Patent No. 7,800,923 - "Offline Synchronous Switching Regulator" (Issued Sept. 21, 2010)
- Technology Synopsis: This patent discloses an offline switching regulator where switches on the primary side generate a switching signal on the secondary side of a transformer. A switching circuit uses this signal and a feedback signal to generate pulse signals that control a synchronous switch for rectification. The system is designed to integrate the regulation and rectification functions to improve efficiency without needing additional components like a magnetic amplifier ('923 Patent, Abstract; col. 1:30-34).
- Asserted Claims: Independent Claim 12 (a method claim) (Compl. ¶54).
- Accused Features: The complaint alleges the InnoSwitch family of products practices an infringing method involving switching a transformer to generate signals, transferring pulse signals to a latch, and controlling a power switch accordingly (Compl. ¶54).
U.S. Patent No. 7,102,211 - "Semiconductor Device and Hybrid Integrated Circuit Device" (Issued Sept. 5, 2006)
- Technology Synopsis: This patent addresses the problem of heat dissipation in semiconductor devices. The invention describes a physical package structure for an integrated circuit where "common leads" are coupled to the internal island (on which the semiconductor die sits) and project out from the resin body. These projecting common leads have a "coupling portion" that allows them to be bridged with brazing material when mounted, creating a larger surface area to dissipate heat away from the chip and improve thermal performance ('211 Patent, Abstract; col. 2:3-12).
- Asserted Claims: Independent Claims 1 and 5 (Compl. ¶62).
- Accused Features: The complaint alleges the InnoSwitch and SCALE-iDriver products infringe by including a hybrid integrated circuit board with a semiconductor element, leads, and a resin-sealing body arranged in an infringing manner (Compl. ¶62, ¶19).
III. The Accused Instrumentality
- Product Identification: The complaint accuses the "InnoSwitch family of products," including the InnoSwitch-CH, -EP, -CP, and -CE families, and specific part numbers such as SC1224K (Compl. ¶15, ¶22). The SCALE-iDriver family is also accused of infringing the ’211 patent (Compl. ¶62).
- Functionality and Market Context: The complaint identifies the accused InnoSwitch products as semiconductors included in fast-charging power adapters, such as the 18W USB Type-C charger distributed with the Google Pixel phone (Compl. ¶6, ¶15). The complaint provides an image of the disassembled charger showing an "InnoSwitch SC1224K product mounted on the circuit board" (Compl. p. 5). The accused functionality is primarily "synchronous rectification," which the complaint alleges offers "improved efficiency and reduced power consumption" (Compl. ¶18). Defendant's marketing materials are cited to claim that InnoSwitch products are designed for fast charging protocols like USB-PD and that they "optimize the effectiveness of output synchronous rectification, resulting in extremely high efficiency" (Compl. ¶16, ¶18).
IV. Analysis of Infringement Allegations
U.S. Patent No. 7,440,298 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A synchronous rectification circuit of the power converter, comprising: a power switch, coupled to a transformer for rectification; | The complaint alleges the InnoSwitch products are or include a power converter with a synchronous rectification circuit that includes a power switch. | ¶22 | col. 3:55-60 |
| and a switching-control circuit, generating a control signal in response to a magnetized voltage of the transformer, a demagnetized voltage of the transformer, and a magnetization period of the transformer, | The complaint alleges the InnoSwitch products contain a switching-control circuit that generates a control signal in an infringing manner. | ¶22 | col. 4:1-26 |
| wherein the control signal is coupled to control the power switch, and the enable period of the control signal is correlated to a demagnetization period of the transformer. | The complaint alleges the switching-control circuit in the InnoSwitch products is arranged to control the power switch as claimed. | ¶22 | col. 4:56-67 |
- Identified Points of Contention:
- Functional Questions: The complaint provides a conclusory allegation that the InnoSwitch products operate "in accordance with claim 1" (Compl. ¶22). A central question will be whether the accused switching-control circuit actually generates its control signal "in response to a magnetized voltage..., a demagnetized voltage..., and a magnetization period" as required by the claim. The case may turn on what evidence shows the accused device uses these specific three inputs to predictively calculate the demagnetization period, versus using another control scheme (such as direct current sensing) to achieve a similar outcome.
- Scope Questions: The term "correlated to" may become a point of contention, raising the question of how direct the relationship must be between the control signal's enable period and the transformer's demagnetization period.
U.S. Patent No. 7,564,705 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A synchronous rectification circuit for a power converter, comprising: a power switch, coupled to a magnetic device for rectification; | The complaint alleges the InnoSwitch products contain a power converter with a synchronous rectification circuit that includes a power switch. | ¶30 | col. 3:60-63 |
| and a switching-control circuit, generating a control signal in response to a magnetized voltage of the magnetic device and a demagnetized voltage of the magnetic device, | The complaint alleges the InnoSwitch products contain a switching-control circuit arranged in an infringing manner. | ¶30 | col. 4:1-12 |
| wherein the control signal is coupled to control the power switch to determine a demagnetization period of the magnetic device. | The complaint alleges the switching-control circuit in the InnoSwitch products controls the power switch to determine the demagnetization period as claimed. | ¶30 | col. 4:6-9 |
- Identified Points of Contention:
- Technical Questions: Similar to the '298 patent analysis, a key factual dispute will likely be the precise mechanism of the accused control circuit. The complaint alleges infringement but does not detail how the InnoSwitch circuit generates its control signal (Compl. ¶30). The litigation will likely require discovery into whether the accused device's operation relies on measuring or deriving signals corresponding to the "magnetized voltage" and "demagnetized voltage" to "determine" the demagnetization period, as claimed.
- Scope Questions: The scope of "determine a demagnetization period" may be disputed. This raises the question of whether the claim requires a predictive calculation of the full period, as described in the specification, or if it could read on a circuit that simply reacts to conditions that signify the end of the period.
V. Key Claim Terms for Construction
For U.S. Patent Nos. 7,440,298 and 7,564,705
- The Term: "switching-control circuit, generating a control signal in response to..."
- Context and Importance: This functional language is the core of the inventions. The infringement analysis for both patents will depend entirely on whether the accused InnoSwitch products perform this specific function using the claimed inputs. Practitioners may focus on this term because it defines the novelty over prior art that used direct current sensing.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claims use the general phrase "in response to," which a plaintiff might argue does not require a specific mathematical calculation but merely a functional dependency. The specification describes the control circuit (100) broadly as being used for "generating a control signal" ('298 Patent, col. 3:59-60).
- Evidence for a Narrower Interpretation: A defendant may argue that the term must be limited to the embodiment described in the specification, which involves a predictive calculation using a capacitor and various voltage-to-current converters ('298 Patent, Figs. 4, 7; col. 4:1-45). The specification repeatedly emphasizes that the invention's purpose is to "predict" the period based on specific voltage and time inputs, which could support a narrower construction requiring such a predictive mechanism ('298 Patent, col. 4:46-51).
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement against Power Integrations for all asserted patents. The basis for inducement is the allegation that Power Integrations provides its InnoSwitch products to be incorporated into downstream products (like the Google Pixel charger) and provides "product briefs, specification sheets and/or instructions on how to incorporate the accused products" in an infringing manner (e.g., Compl. ¶23-24, ¶31-32).
- Willful Infringement: Willfulness is alleged based on knowledge of the patents "at least as early as the filing of this Complaint" (e.g., Compl. ¶23, ¶31). This frames the willfulness claim as being based on post-suit conduct, a standard pleading practice. No specific facts supporting pre-suit knowledge are alleged.
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of technical operation: Does the accused InnoSwitch family of products, which is marketed as using "synchronous rectification," actually implement the specific predictive control logic recited in the asserted claims ('298, '705, '407, '923 patents)? Or does it achieve high efficiency through a different, non-infringing control method? The case will likely depend on detailed evidence of the accused circuits' internal functionality.
- A second key question will be one of claim construction: Can the functional claim language, such as generating a signal "in response to a magnetized voltage... a demagnetized voltage, and a magnetization period," be interpreted broadly to cover any control scheme that is functionally dependent on those parameters, or must it be limited to the specific predictive calculation circuits disclosed in the patent specifications?
- Finally, for the '211 patent, the dispute will likely turn on a structural comparison: Does the physical package of the accused InnoSwitch and SCALE-iDriver products include the claimed "common leads" with a "coupling portion" designed to enhance heat dissipation in the specific manner described by the patent? This will be a factual question resolved by physical analysis of the accused products.