DCT
1:25-cv-22599
Shenzhen Hehong Technology Co Ltd v. Luo
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Shenzhen Hehong Technology Co., Ltd. and Shenzhen Dushu Culture Advertising Co., Ltd. (China)
- Defendant: Xiaohua Luo (China)
- Plaintiff’s Counsel: Law Firm of Rubio & Associates, P.A.
- Case Identification: 25-cv-22599, S.D. Fla., 10/16/2025
- Venue Allegations: Plaintiffs allege venue is proper because the dispute arises from Defendant’s use of Amazon's APEX process to target product listings accessible for sale in the Southern District of Florida, and all parties conduct business in the district.
- Core Dispute: Plaintiffs seek a declaratory judgment that their decorative string-light controller products do not infringe Defendant's U.S. Patent No. 9,723,679, and that the patent is invalid.
- Technical Context: The technology concerns electronic circuits that use a single power supply line to transmit both power and control signals, primarily for controlling arrays of Light Emitting Diodes (LEDs).
- Key Procedural History: The dispute was initiated by Defendant Xiaohua Luo filing a complaint through Amazon's Patent Evaluation Express (APEX) procedure, alleging that Plaintiffs' products infringe the patent-in-suit. This action prompted Plaintiffs to file for a declaratory judgment of non-infringement and invalidity to prevent the removal of their product listings from the e-commerce platform.
Case Timeline
| Date | Event |
|---|---|
| 2014-10-10 | ’679 Patent - Earliest Priority Date |
| 2017-08-01 | ’679 Patent - Issue Date |
| 2025-03-31 | Defendant executed APEX Agreements asserting infringement |
| 2025-04-21 | Deadline for Plaintiffs to respond to Amazon's APEX notification |
| 2025-10-16 | Complaint for Declaratory Judgment filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,723,679 - "COMPUTING APPARATUS AND LED DRIVER"
- Patent Identification: U.S. Patent No. 9,723,679, "COMPUTING APPARATUS AND LED DRIVER," issued August 1, 2017 (’679 Patent).
The Invention Explained
- Problem Addressed: The patent's background section describes that conventional LED control systems, such as those based on the DMX512 protocol, require one or more independent signal lines in addition to power and ground lines to transmit control signals. This makes them unsuitable for applications where only a power supply line and a ground line are available (’679 Patent, col. 2:46-53).
- The Patented Solution: The invention discloses a "computing apparatus" that is powered by and receives control signals from the same power supply line. The core of the apparatus is an "edge-triggered computing device" that performs computations based on detecting the rising and falling edges of signals on the power line (’679 Patent, Abstract). This is coupled with a charging device that draws power from the line and an initialization device that resets the computing device, enabling complex control over devices like LEDs without extra wiring (’679 Patent, Fig. 1; col. 2:60-68).
- Technical Importance: This approach simplifies the wiring and on-chip implementation for complex lighting displays by combining power and data transmission onto a single electrical line (’679 Patent, Abstract).
Key Claims at a Glance
- The complaint asserts non-infringement of independent Claim 1 (Compl. ¶10).
- Essential Elements of Claim 1:
- A computing apparatus configured to be triggered by input signal edges from a power supply line, comprising an edge-triggered computing device, a charging device, and an initialization device.
- The edge-triggered computing device is configured to be triggered to perform computing by the input signal edges from the power supply line and to output computing results.
- The charging device is configured to supply power to the edge-triggered computing device based on the input signals from the power supply line.
- The charging device is charged when the input signal from the power supply line is at a high voltage and is discharged when the input signal is at a low voltage.
- The initialization device is configured to initialize the edge-triggered computing device based on the voltage of the power supplied by the charging device.
- The complaint does not explicitly reserve the right to assert dependent claims, as it is a declaratory judgment action focused on Claim 1.
III. The Accused Instrumentality
Product Identification
- Plaintiffs' "string-light controller products including RGB music-sync changing lights," sold on Amazon under ASINs B08BJ5Y4PN, B0DFCJR3YN, and B0D3QNSK9N (Compl. ¶17, ¶20).
Functionality and Market Context
- The complaint alleges the accused products operate on a fundamentally different principle from the patented invention (Compl. ¶13). Instead of detecting signal edges, the products' controllers decode signals by comparing the power line signal to a stable reference voltage and measuring the duration of high and low voltage levels (i.e., pulse-width modulation) (Compl. ¶13, ¶15, ¶27).
- The complaint further alleges that the products use a simple resistor-capacitor (RC) network for power-on-reset, contrasting this with what it characterizes as the patent's more complex multi-MOS transistor configuration (Compl. ¶13). These products are described as mass-market decorative lights (Compl. ¶15).
IV. Analysis of Infringement Allegations
The complaint seeks a declaratory judgment of non-infringement. The following table summarizes the key distinctions Plaintiffs allege between the elements of Claim 1 and the functionality of their accused products.
’679 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Non-Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| an edge-triggered computing device... configured to be triggered to perform computing by the input signal edges from the power supply line | The accused products' signal decoding is performed by a clock generator and logic modules that decode pulse-width-modulated signals by measuring duration of voltage levels, not by computations triggered directly by signal edges. | ¶27 | col. 14:7-11 |
| a charging device... charged when the input signal from the power supply line is at a high voltage, and is discharged when the input signal from the power supply line is at a low voltage | The accused products' charging device allegedly includes actively regulated PMOS-controlled circuits and MOS capacitors, differing from the passive diode-capacitor configuration described in the patent. | ¶28 | col. 14:15-20 |
| an initialization device is configured to initialize the edge-triggered computing device based on the voltage of the power supplied by the charging device | The accused products' initialization device allegedly consists of a logic-driven reset architecture using Schmitt triggers and oscillator timing, not a passive, voltage-based initialization tied to the charging device's voltage. | ¶29 | col. 14:21-25 |
- Identified Points of Contention:
- Scope Questions: A primary dispute will concern the scope of "edge-triggered computing." The question is whether this term, as used in the patent, is limited to circuits that directly count or react to discrete rising and falling signal edges (as disclosed in the patent's D-flip-flop embodiments), or if it could be interpreted more broadly to read on systems that measure the duration between such edges (i.e., pulse-width decoding).
- Technical Questions: The complaint raises a question of technical and structural non-equivalence. It alleges the accused products use "fundamentally different" hardware, such as actively regulated PMOS circuits for charging and logic-driven Schmitt triggers for initialization, in contrast to the patent's disclosure of more passive, voltage-dependent diode-and-transistor-based circuits (Compl. ¶16, ¶28-29).
No probative visual evidence provided in complaint.
V. Key Claim Terms for Construction
- The Term: "edge-triggered computing device"
- Context and Importance: This term is the central focus of the non-infringement argument. Plaintiffs contend their products are not "edge-triggered" but rather rely on measuring signal duration (Compl. ¶27). The case will likely depend heavily on whether the accused products' pulse-width decoding method falls within the court's construction of this term.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language states the device is "triggered to perform computing by the input signal edges" (’679 Patent, col. 14:8-9). A patentee might argue that any computation that logically follows a signal transition (an edge) meets this limitation, including measuring the time until the next transition.
- Evidence for a Narrower Interpretation: The specification's preferred embodiments consistently describe an "edge counting device" comprising a "plurality of D flip-flops connected in series" where the clock inputs are connected to the power supply line to detect edges (’679 Patent, col. 2:49-51; col. 3:1-7; Fig. 2). Plaintiffs may argue that this repeated emphasis on specific edge-counting hardware limits the term to circuits that directly count signal transitions, rather than measure pulse durations.
VI. Analyst’s Conclusion: Key Questions for the Case
This declaratory judgment action appears to center on two critical questions for the court:
- A core issue will be one of definitional scope: Can the term "edge-triggered computing device," which the patent specification exemplifies with circuits that count discrete signal transitions, be construed broadly enough to cover the accused products' system, which allegedly operates by measuring the duration of voltage levels (pulse-width)?
- A secondary issue may be one of structural and functional equivalence: Even if the claim scope is found to be broad, do the accused products' alleged use of actively-regulated charging circuits and logic-driven reset mechanisms constitute a "fundamentally different" architecture that is not equivalent to the passive, voltage-based circuits described and claimed in the ’679 Patent?