Comarco Wireless Systems LLC v. Walgreen Co.

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Comarco Wireless Systems LLC (Texas)
  • Defendant: Walgreen Co. (Illinois)
  • Plaintiff’s Counsel: Direction IP Law
• Case Identification: 4:23-cv-01111, E.D. Tex., 12/15/2023
• Venue Allegations: Venue is based on Defendant maintaining multiple established places of business within the Eastern District of Texas.
• Core Dispute: Plaintiff alleges that Defendant’s sale of certain USB chargers and portable power banks infringes three patents related to power supply systems that communicate with portable electronic devices to control battery charging safely.
• Technical Context: The technology addresses the need for intelligent communication between power sources and portable devices to ensure appropriate power levels are delivered, preventing damage or hazards from electrical mismatches.
• Key Procedural History: The complaint alleges that Plaintiff sent Defendant a notice letter on September 15, 2023, which included infringement charts for the asserted patents. This event forms the basis for Plaintiff's allegations of willful infringement. The patents-in-suit claim priority to a 2004 patent application, indicating a long history of prosecution and development in this technology area.

Case Timeline

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

U.S. Patent No. 9,413,187 - "Power Supply System Providing Power and Analog Data Signal for Use by Portable Electronic Device to Control Battery Charging"

The Invention Explained

• Problem Addressed: The proliferation of portable devices and various power sources (e.g., wall sockets, car outlets) created a risk of connecting a device to an inappropriate power level, which could result in charging failure, device damage, battery overheating, or fire (Compl. ¶10).
• The Patented Solution: The invention describes a power supply system where the charger and the portable device communicate through a "handshake" process. The system uses a four-conductor connection to transfer DC power, provide a ground reference, receive a first signal from the portable device, and transmit a second, analog signal back to the device. This second signal informs the device about the power supply's characteristics, allowing the device to control its own battery charging accordingly (’187 Patent, Abstract; Compl. ¶11). The patent's background discusses the specific problem of distinguishing between automobile and airplane (EMPOWER) power sources, which have different voltage ranges and safety requirements for battery charging (’187 Patent, col. 1:40-2:51).
• Technical Importance: This approach allows a single power adapter to intelligently and safely charge a variety of devices from different power sources by delegating the final charging control to the electronic device itself based on information provided by the power supply (Compl. ¶11).

Key Claims at a Glance

• The complaint asserts independent claims 1 and 7 (Compl. ¶27).
• Essential elements of Independent Claim 1 include:
  • A system with a portable electronic device (with a battery) and an external power supply.
  • The power supply has power circuitry for DC power and data circuitry.
  • The data circuitry receives a first signal from the portable device and, in response, provides a second, analog signal.
  • A four-conductor connector transfers DC power, ground, the first signal, and the second signal.
  • The portable device uses the second signal's parameter level to control charging of its battery.
• The complaint reserves the right to assert dependent claims 2 and 8-9 (Compl. ¶27).

U.S. Patent No. 10,855,087 - "Power Supply Systems"

The Invention Explained

• Problem Addressed: The patent's background describes the risk that arises when a user forgets to change connectors for a DC/DC adapter when moving between different power environments, such as from a car to an airplane. Using the wrong connector could improperly signal the portable device, leading it to dangerously recharge batteries when it should not (’087 Patent, col. 2:38-52).
• The Patented Solution: The invention claims a power supply system with circuitry that provides DC power and communicates with a portable electronic device (PED) via a four-conductor connector. The data circuitry receives an "input signal" from the PED and provides an "output signal" back to it. This output signal has a "parameter level" that the PED can use to control the charging of its own battery, thereby enabling an intelligent and safe charging process based on the power source's characteristics (’087 Patent, Abstract; col. 3:31-4:15).
• Technical Importance: This system enables a power supply to automatically communicate its capabilities or the nature of its power source to a connected device, offloading the final charging logic to the device itself and enhancing safety (’087 Patent, col. 2:53-60).

Key Claims at a Glance

• The complaint asserts independent claims 1 and 11 (Compl. ¶44, p. 58).
• Essential elements of Independent Claim 1 include:
  • A power supply system with power circuitry and data circuitry.
  • The data circuitry is configured to receive a first signal from a portable device and provide a second signal back to it.
  • A four-conductor connector is configured to transfer DC power, ground, the first signal, and the second signal.
  • The second signal has a parameter level usable by the portable device to control charging based on the DC power provided.
• The complaint reserves the right to assert dependent claims 2, 5-8, 12, and 15-18 (Compl. ¶44, p. 58).

U.S. Patent No. 10,951,042 - "Power Supply Systems"

• Technology Synopsis: Similar to the ’087 Patent, this patent describes a system where a portable electronic device and a power supply engage in a signaling handshake to ensure safe battery charging. The claims focus on the portable electronic device itself, which contains power circuitry to receive DC power and data circuitry to provide a first signal to, and receive a second signal from, the power supply to control charging (’042 Patent, Abstract).
• Asserted Claims: Independent claims 1 and 11 are asserted (Compl. ¶71, p. 121).
• Accused Features: The complaint accuses various Belkin and Infinitive branded portable power banks, such as the "Belkin 10,000 mAh Portable PowerBank" and "Infinitive Power Bank 5000mAh" (Compl. ¶71, p. 121).

III. The Accused Instrumentality

Product Identification

• The complaint accuses two categories of products sold by Defendant:
  1. Accused Chargers: Various Belkin-branded USB-C wall and car chargers, such as the "Belkin USB-C PD 3.0 PPS Wall Charger 25W" (Compl. ¶27, ¶44).
  2. Accused Devices: Various Belkin and Infinitive-branded portable power banks (Compl. ¶71).

Functionality and Market Context

• The complaint alleges that the Accused Chargers and Devices are external power supplies that provide DC power to portable electronic devices (e.g., mobile phones) via a USB cable (Compl. ¶28, ¶72).
• The infringement theory is grounded in the products' alleged compliance with the USB Battery Charging (BC) 1.2 specification (Compl. ¶28). The complaint alleges that this standard employs a "Primary Detection" method where a portable device sends a signal on the D+ data line of a USB connector, and the charger responds by shorting the D+ and D- lines through a resistor. This creates a modified signal on the D- line that the portable device receives and interprets to determine the type of charging port it is connected to, thereby controlling how much current it draws (Compl. ¶30, ¶33, ¶34). The complaint includes a circuit diagram from the USB BC 1.2 specification to illustrate this alleged mechanism (Compl. p. 10, Figure 3-6).

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,413,187 Infringement Allegations

U.S. Patent No. 10,855,087 Infringement Allegations

Identified Points of Contention

• Technical Questions: The complaint's infringement theory hinges on the operation of the USB BC 1.2 standard. A central question will be whether the D- signal, which the complaint describes as a voltage-dropped version of the D+ signal, is "provided by" the charger's data circuitry as claimed, or if it is merely a passive modification of a signal that originates from and is returned to the portable device. The complaint repeatedly pleads infringement under the doctrine of equivalents for this element, suggesting an anticipated dispute over the literal meaning of "provide a second signal" (Compl. ¶30, ¶37, ¶41).
• Scope Questions: The '187 Patent requires the second signal to be "analog." The complaint's basis is that the device compares the signal's voltage to a reference (Compl. ¶33). A potential point of contention is whether this voltage comparison constitutes use of an "analog signal" as understood in the patent, or if it is functionally a binary threshold detection that does not read on the claim.

V. Key Claim Terms for Construction

• The Term: "data circuitry...to provide a second signal" (or "output signal")
• Context and Importance: This term is central to the infringement analysis for all asserted patents. The complaint alleges that the Accused Chargers' circuitry, by shorting the D+ and D- lines through a resistor, "provides" the D- signal (Compl. ¶30, ¶46). The case may turn on whether this passive electrical arrangement meets the claim requirement that the data circuitry "provides" a signal, as opposed to merely modifying one.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent specifications describe the overall system function of communicating power capability from the supply to the device. A court could find that any circuitry, active or passive, that achieves this communicative function falls within the claim scope, consistent with the patent's purpose (’087 Patent, Abstract).
  • Evidence for a Narrower Interpretation: The embodiments described in the patents appear to contemplate more active circuitry. For example, the block diagrams show distinct "Control circuitry," "Comparison circuitry," and "Post-regulation circuitry" which suggest active logic components rather than a simple resistive path (’087 Patent, Fig. 3). This may support a narrower construction that excludes the alleged mechanism.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement. The inducement theory is based on Defendant selling the Accused Chargers with the knowledge and intent that customers will use them in an infringing manner with portable devices, aided by instructions and advertisements (Compl. ¶43-44).
• Willful Infringement: Willfulness is alleged based on Defendant’s continued infringing activities after receiving a detailed notice letter from Plaintiff on September 15, 2023, which allegedly included claim charts demonstrating the infringement (Compl. ¶46, ¶69, ¶92).

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

• A core issue will be one of technical and definitional scope: does the passive mechanism of shorting USB data lines through a resistor, as allegedly practiced by the Accused Products under the BC 1.2 standard, constitute "data circuitry" that "provides" a "second signal" as those terms are used in the patents-in-suit? The resolution will depend on whether the claims are construed to cover passive signal modification or require active signal generation.
• A key alternative question will be one of functional equivalence: if the accused mechanism does not literally infringe, is the creation of a voltage-dropped D- signal insubstantially different from the patented method of providing a second signal to control charging? The plaintiff's repeated pleading of the doctrine of equivalents indicates this will be a central battleground.
• A critical factual issue for damages will be willfulness: what was the content of the September 15, 2023 notice letter, and can Plaintiff establish that Defendant's continued sales after receiving this notice constituted an unjustifiably high risk of infringement that was either known or so obvious it should have been known?