DCT
1:24-cv-00131
IFPower Co Ltd v. ASUSTeK Computer Inc
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: IFPower Co., Ltd. (Taiwan)
- Defendant: Zagg, Inc. (Delaware)
- Plaintiff’s Counsel: DiNovo Price LLP
- Case Identification: 1:23-cv-01501, W.D. Tex., 04/25/2025
- Venue Allegations: Venue is based on Defendant having an established place of business in the Western District of Texas.
- Core Dispute: Plaintiff alleges that Defendant’s Qi-compliant wireless charging products, including Mophie-branded chargers and battery cases, infringe patents related to adaptive frequency control in charging transmitters and integrated wireless charging circuits in battery covers.
- Technical Context: The technology concerns inductive wireless power transfer, a field largely governed by the Wireless Power Consortium's (WPC) Qi standard for consumer electronics.
- Key Procedural History: This is a Second Amended Complaint. U.S. Patent No. 7,298,361 was subject to an ex parte reexamination, which concluded with a certificate issued on October 15, 2024, confirming the patentability of asserted claim 1.
Case Timeline
| Date | Event |
|---|---|
| 2004-12-07 | U.S. Patent No. 7,298,361 Priority Date |
| 2007-06-29 | U.S. Patent No. 7,863,860 Priority Date |
| 2007-11-20 | U.S. Patent No. 7,298,361 Issue Date |
| 2009-08-01 | WPC published the Qi low-power specification |
| 2011-01-04 | U.S. Patent No. 7,863,860 Issue Date |
| 2025-04-25 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,298,361, Non-Contact Electric Inductance Circuit for Power Source, Issued Nov. 20, 2007
- The Invention Explained:
- Problem Addressed: The patent describes that in the manufacturing of early wireless chargers, minor variations in electronic components like inductors and capacitors could cause the device’s actual operating frequency to differ from its intended frequency, reducing charging efficiency (’361 Patent, col. 1:38-46). Correcting this mismatch required "cumbersome and repeated adjustment actions" during production, which lowered manufacturing yield (Compl. ¶¶13-14; ’361 Patent, col. 1:49-54).
- The Patented Solution: The invention proposes an automated, dynamic tuning system. It uses a feedback circuit to monitor the voltage or current of the power-transmitting harmonic circuit and sends this data to a micro-processing circuit (’361 Patent, Fig. 1). The micro-processor analyzes the signal and adjusts an oscillating circuit’s frequency in real-time to generate the "best harmonic frequency," thereby compensating for any component-level variations and optimizing performance (Compl. ¶15; ’361 Patent, col. 2:5-15).
- Technical Importance: The technology aimed to automate the frequency tuning process, which could "completely save the cumbersome adjusting operation during the process of production" and improve product consistency (’361 Patent, col. 3:39-42).
- Key Claims at a Glance:
- The complaint asserts at least independent claim 1 and dependent claim 2 (Compl. ¶¶39, 60).
- The essential elements of independent claim 1 are:
- A non-contact electric inductance circuit for a power source that amplifies an alternating current from an oscillator and passes it to a harmonic circuit.
- The circuit includes a feedback circuit, a micro-processing circuit, and an "adapted-to-adjusting-frequency oscillating circuit" integrated together.
- The feedback circuit transmits the voltage or current of the harmonic circuit to the micro-processing circuit.
- The micro-processing circuit analyzes the quality of the harmonic vibration and compares it to a pre-set quality standard.
- The oscillating circuit then "adjusts frequency to get the best harmonic frequency."
U.S. Patent No. 7,863,860, Battery Cover, Issued Jan. 4, 2011
- The Invention Explained:
- Problem Addressed: The patent notes the inconvenience of conventional charging methods, which required either physically removing batteries from a device to place them in a separate charger or connecting the entire device to a power source with a cable, which could lead to wear and an accumulation of different chargers ('860 Patent, col. 1:29-2:2; Compl. ¶20).
- The Patented Solution: The invention is a replacement battery cover that integrates all the necessary circuitry for wireless charging. The cover contains a receiving coil, power conversion circuits, and pins that connect to the device's battery terminals ('860 Patent, Fig. 1). This allows a user to make a standard, non-wireless-capable device (like a game controller) chargeable by simply swapping its original battery cover for the invented one and placing it on a compatible charging pad ('860 Patent, col. 2:5-12; Compl. ¶21).
- Technical Importance: The invention provided a way to retrofit existing electronic devices for wireless charging compatibility without modifying the device itself, offering a convenient upgrade path for consumers.
- Key Claims at a Glance:
- The complaint asserts at least independent claim 1 (Compl. ¶79).
- The essential elements of independent claim 1 are:
- A battery cover adapted for placement on an RF emitter for non-touch charging.
- The cover is used to cover a "battery groove" of an electric appliance and has pins to connect with chargeable batteries.
- It contains a "non-touch induction type electric power generating unit" which includes:
- A "first harmonic oscillation circuit" with a first coil to receive energy from an RF emitter.
- A "rectifying wave filtering circuit" to convert the received energy to DC current.
- An "electric charging circuit" to charge the batteries.
- A "first processing unit" to detect the state of charge.
- A "first modulating circuit" that uses a "load changing mode" to transmit data (like state of charge) back through the first coil.
III. The Accused Instrumentality
- Product Identification: The complaint accuses Zagg’s wireless charging products, sold under its "Mophie" brand and other lines, that are designed to comply with the Wireless Power Consortium (WPC) Qi wireless charging standard (Compl. ¶¶25-26). These include both "Power Transmitters" (e.g., charging pads, stands) and "Power Receivers" (e.g., "juice pack" battery cases) (Compl. ¶¶61, 80). The complaint provides a multi-page list of accused Qi-certified Mophie products (Compl. ¶28).
- Functionality and Market Context: The accused products function as a wireless power transfer system according to the Qi standard. The transmitter generates a magnetic field, and the receiver converts that field into electrical current to charge a device’s battery (Compl. ¶¶33, 44, 75). The system includes a communication protocol where the receiver sends information packets (e.g., control error, state of charge) to the transmitter by modulating the power load, and the transmitter adjusts its operating frequency and voltage to manage the power transfer (Compl. ¶¶35-38, 55). The complaint alleges Zagg represents these products as compliant with the Qi standard and instructs customers on their use (Compl. ¶26).
IV. Analysis of Infringement Allegations
’361 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A non-contact electric inductance circuit for a power source, said circuit amplifies an alternative current generated by an oscillator through a circuit driving circuit and pass to a harmonic circuit | The accused Qi-compliant Power Transmitters implement a Power Conversion Unit with an inverter (oscillator), driving circuit, and a primary coil (harmonic circuit) to generate an AC field for power transfer. A visual representation is provided in a Qi specification block diagram. (Compl. p. 23). | ¶33, ¶62 | col. 2:5-9 |
| said electric inductance circuit has a feedback circuit, a micro-processing circuit and an adapted-to-adjusting-frequency oscillating circuit integrated with one another | The accused products allegedly use a "Communications and Control Unit" (micro-processing circuit) that executes a PID control algorithm based on feedback from the receiver to control the inverter (oscillating circuit). The complaint presents a diagram of this PID control loop. (Compl. p. 24). | ¶36, ¶63 | col. 2:1-5 |
| said feedback circuit transmits voltage or current of said harmonic circuit to said micro-processing circuit that analyses quality of harmonic vibration practically generated... and obtains by comparing the degree of difference... | The Qi receiver sends "Control Error" messages to the transmitter's control unit. This message allegedly represents the difference between the actual and desired power transfer, which the complaint maps to the analysis of "quality of harmonic vibration." | ¶37 | col. 4:32-36 |
| then said adapted-to-adjusting-frequency oscillating circuit adjusts frequency to get the best harmonic frequency | The transmitter's control unit uses the PID algorithm to adjust the "Operating Frequency" of the inverter to manage power transfer, allegedly to achieve the "best harmonic frequency." Mophie product manuals state an operating frequency range of 112 kHz–205 kHz. | ¶37, ¶64 | col. 4:36-40 |
- Identified Points of Contention:
- Scope Questions: The infringement theory equates the Qi standard's digital "Control Error" packet, sent from a separate receiver device, with the patent's "feedback circuit" that "transmits voltage or current of said harmonic circuit." A key question is whether this digital, system-level feedback loop falls within the scope of the claimed, seemingly internal and analog, feedback circuit.
- Technical Questions: Does the Qi algorithm's goal of adjusting frequency to meet a power target requested by the receiver constitute an adjustment "to get the best harmonic frequency," as claimed? The patent's focus is on correcting for static manufacturing variations, which raises the question of whether the dynamic, load-responsive adjustments in the Qi protocol perform the same function in the same way.
’860 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A battery cover adapted to placing on an RF (radio frequency) emitter... said battery cover at least comprises: a cover used to cover a battery groove of an electric appliance... | The accused products include Mophie "juice pack" cases and other products that function as battery covers for devices like smartphones. The complaint provides internal photos of an accused Zagg keyboard showing a battery and charging coil inside the cover. (Compl. p. 33). | ¶44-45 | col. 6:10-14 |
| a non-touch induction type electric power generating unit provided in said cover... includes: a first harmonic oscillation circuit having a first coil | Accused Power Receivers implement a "Power Pick-up Unit" containing a "Secondary Coil" and resonant circuit, as specified by the Qi standard, to generate power from the RF emitter's field. A block diagram of a Qi receiver is provided in the complaint. (Compl. p. 35). | ¶46-48 | col. 6:23-27 |
| a rectifying wave filtering circuit connecting with said first harmonic oscillation circuit, to make said energy source become electric DC current | The accused products, per the Qi standard, implement a "Rectification circuit" to convert the AC waveform from the secondary coil into DC current to charge the battery. | ¶50 | col. 6:28-30 |
| a first processing unit connecting with said electric charging circuit to detect state of charging of said chargeable batteries | The Qi standard's "Communications and Control Unit" in the receiver monitors the system and load, which the complaint alleges corresponds to detecting the state of charge. | ¶53 | col. 6:34-36 |
| a first modulating circuit... for releasing signals of state of charging by a load changing mode to transmit data through said first coil | The Qi standard specifies that Power Receivers use a "communications modulator" to vary their electrical load. This load modulation transmits data packets (e.g., state of charge) back to the transmitter via the magnetic field coupling the coils. | ¶55 | col. 6:37-42 |
- Identified Points of Contention:
- Scope Questions: Can the term "battery cover" used to cover a "battery groove", which the patent illustrates with a simple lid for a removable-battery compartment (e.g., on a game controller), be construed to read on an integrated charging case (like a Mophie "juice pack") that fully encloses a smartphone? The definition of "battery groove" will be a central issue.
- Technical Questions: The complaint alleges infringement by a wide range of Qi-compliant products. A factual question will be whether each accused product family actually implements the specific "load changing mode" of communication and other circuit details as required by the claim and alleged by the plaintiff.
V. Key Claim Terms for Construction
For the ’361 Patent
- The Term: "best harmonic frequency"
- Context and Importance: This term defines the objective of the claimed frequency adjustment. The infringement analysis depends on whether the accused Qi-compliant products adjust their frequency to achieve this specific goal. Practitioners may focus on this term because its definition could distinguish the patent’s inventive concept (compensating for manufacturing flaws) from the accused products' function (managing power delivery).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states the circuit adjusts frequency "in order that the entire electric inductance circuit for the power source can generate the best harmonic frequency" ('361 Patent, col. 2:13-15), which a plaintiff might argue refers to the optimal frequency for any given condition.
- Evidence for a Narrower Interpretation: The patent’s background exclusively discusses overcoming frequency mismatches from "practical operating efficiencies of inductances... or capacitors" from the same specification ('361 Patent, col. 1:43-46). This suggests the "best" frequency is the pre-determined design frequency that the invention helps the circuit achieve despite component variations.
For the ’860 Patent
- The Term: "battery cover"
- Context and Importance: The primary accused products are integrated battery cases for smartphones. Whether these products meet the definition of a "battery cover" is fundamental to the infringement claim. Practitioners may focus on this term because many accused products are arguably more than just a simple "cover."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is general: "a cover used to cover a battery groove of an electric appliance" ('860 Patent, col. 6:13-14). Plaintiff may argue this broadly covers any accessory that encloses the part of a device where a battery is located.
- Evidence for a Narrower Interpretation: The patent's preferred embodiments and figures consistently depict a simple, removable lid for a compartment holding standard AA-type batteries in devices like a game controller ('860 Patent, Fig. 1). A defendant could argue the term is limited to this context and does not include a full-enclosure case with its own integrated battery.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for both patents. The allegations for inducement are based on Zagg's knowledge of the patents (from at least the original complaint filing) combined with providing products and instructive user guides that allegedly encourage customers to operate the devices in an infringing manner (Compl. ¶¶70, 87). The contributory infringement allegations state that Zagg's products are not staple articles of commerce and are especially adapted to infringe by being designed to comply with the Qi standard (Compl. ¶¶71, 88).
- Willful Infringement: The complaint alleges willfulness based on Zagg’s continued infringement after being notified of the patents and the alleged infringement via the original complaint in this lawsuit (Compl. ¶¶90-91).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: Can the term "battery cover" for a "battery groove", which is rooted in the patent’s context of replaceable-battery devices, be construed to encompass modern, integrated smartphone charging cases that are themselves complex electronic devices?
- A second central issue will be one of functional purpose: Does the Qi standard’s method of dynamically adjusting operating frequency to regulate power delivery to a load constitute the same function as the ’361 patent’s claimed invention, which adjusts frequency to achieve a "best harmonic frequency" to compensate for static component variations?
- Finally, the case relies heavily on a standards-based infringement theory. A key evidentiary question will be whether the specific technical mandates of the Qi standard, as implemented in Zagg's products, can be proven to map cleanly onto every limitation of the asserted patent claims, or if material operational differences exist.