DCT
1:25-cv-23704
Voltstar Tech Inc v. Sun Jinming
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Voltstar Technologies, Inc. (Illinois)
- Defendant: Sun Jinming a/k/a EGK-US (China)
- Plaintiff’s Counsel: Sriplaw PLLC
- Case Identification: 1:25-cv-23704, S.D. Fla., 08/18/2025
- Venue Allegations: Plaintiff alleges venue is proper because the defendant is not a resident of the United States and has committed acts of infringement in the district.
- Core Dispute: Plaintiff alleges that Defendant’s various electronic chargers, sold online, infringe a patent related to the compact physical design of AC/DC power adapters.
- Technical Context: The technology concerns the mechanical and electrical design of small-footprint power converters, a critical component for the vast market of portable electronic devices.
- Key Procedural History: The patent-in-suit, RE48,794 E, is a reissue of U.S. Patent No. 9,024,581. The complaint notes that the reissue proceeding amended Claim 1 to narrow the claimed dimensions of the charger housing, specifically changing a length limitation from "equal to or less than 2.0 inches" to "less than 2.0 inches" and adding a new width limitation of "less than 1.75 inches." This amendment will likely be a central focus of the infringement analysis.
Case Timeline
| Date | Event |
|---|---|
| 2008-05-21 | Patent Priority Date (RE48,794 E) |
| 2015-05-05 | Issue Date of original U.S. Patent 9,024,581 |
| 2021-10-26 | Issue Date of Reissue Patent RE48,794 E |
| 2025-08-18 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Reissue Patent No. RE48,794 E, "Charger Plug With Improved Package," issued October 26, 2021.
The Invention Explained
- Problem Addressed: The patent’s background section describes problems with prior art charger plugs, noting they are often bulky, interfering with adjacent wall outlets, and have an increased length that makes them susceptible to being struck or dislodged from the wall (’794 Patent, col. 1:42-57). It also identifies manufacturing inefficiencies and costs associated with traditional "insert molding" of power blades and hand-soldering of internal components (’794 Patent, col. 2:1-26).
- The Patented Solution: The invention is a "reduced plug-size charger plug" that simplifies construction and reduces physical dimensions (’794 Patent, Abstract). Instead of molding the power blades into the housing, the blades are separate components that are slidably mounted into the housing and connected to the internal circuitry via spring contacts, obviating the need for soldering (’794 Patent, col. 4:1-17). This design allows for a smaller, more compact package that avoids obstructing adjacent outlets.
- Technical Importance: This approach addressed a market need for smaller, less obtrusive, and more cost-effective chargers for the growing number of portable electronic devices (’794 Patent, col. 1:21-25).
Key Claims at a Glance
- The complaint asserts at least independent Claim 1 (Compl. ¶29).
- Essential elements of Claim 1 include:
- A charger plug for converting 120V input power to DC output power.
- A housing containing first and second separate blade members with prong portions that extend from a front wall.
- A DC connector with an aperture to receive a power cord plug.
- The housing being sized with a longitudinal length of "less than 2.0 inches" and a width of the "housing outer profile being less than 1.75 inches."
- The housing's "outer profile having no interference with an adjacent receptacle of the power source."
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- A series of chargers sold under the "EGK-US" brand on Amazon.com, including models such as the "EGK VR Fast Charger," "15W Fast Charger for Kindle Fire," and various speaker and watch chargers (Compl. ¶21).
Functionality and Market Context
- The complaint alleges the accused products are chargers designed to be connected between an AC power source, like a wall outlet, and a device to be charged (Compl. ¶22). It specifically alleges that the chargers "employ a reduced plug-size" design so that they do not "block or interfere with the use of adjacent outlets" (Compl. ¶23). The products are marketed to consumers throughout the United States via e-commerce stores (Compl. ¶18).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint.
The complaint references a claim chart in its Exhibit 3, which was not attached to the publicly filed document. The following analysis is based on the narrative infringement allegations in the body of the complaint.
RE48,794 E Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A charger plug capable of connecting with a two or three receptacle power source to convert 120V input power received from the power source to DC output power... | Defendant's products are chargers advertised for connection between an AC power source (wall outlet) and a device with a rechargeable battery using DC power. | ¶22 | col. 13:18-24 |
| being sized so that the charger plug housing comprises a longitudinal length extending between the front wall and the rear end and the longitudinal length is less than 2.0 inches, a width of the housing outer profile being less than 1.75 inches... | The chargers distributed by Defendant employ a reduced plug-size charger plug. | ¶23 | col. 13:46-51 |
| ...the outer profile having no interference with an adjacent receptacle of the power source located on all sides of the first receptacle when a like charger plug is mounted in all available orientations in any of the other receptacles... | The chargers do not block or interfere with the use of adjacent outlets upon plugging them into a source of AC power such as a wall outlet. | ¶23 | col. 13:51-59 |
| so that when space is limited by an obstacle adjacent or in front of the power source the charger plug is capable of being conveniently mounted...the power cord plug end may be conveniently received by the DC connector and the power cord plug end can be conveniently removed...while leaving the charger plug connected... | The size and shape of the chargers allow a power cord to be easily inserted and removed while the charger is plugged into the AC source. | ¶24 | col. 14:1-9 |
- Identified Points of Contention:
- Scope Questions: A central issue may be the interpretation of "housing outer profile." The defense may question the precise method for measuring this "profile" to determine if it is indeed "less than 1.75 inches" as required by the claim.
- Technical Questions: The complaint makes a conclusory allegation that the accused chargers have the claimed dimensions and non-interference properties (Compl. ¶23). A key factual question will be whether physical testing and measurement of the accused products confirm they meet the specific numerical limitations ("less than 2.0 inches" and "less than 1.75 inches") introduced during the patent's reissue.
V. Key Claim Terms for Construction
- The Term: "a width of the housing outer profile being less than 1.75 inches" (from Claim 1(i)).
- Context and Importance: This limitation was added during the reissue proceeding that led to the ’794 Patent, suggesting it was critical for establishing patentability over the prior art (Compl. ¶12 & fn. 1). The infringement case against the accused products, which are alleged to be compact chargers, may hinge entirely on whether their measured dimensions fall within this precise numerical boundary.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The complaint does not provide sufficient detail for analysis of evidence supporting a broader interpretation.
- Evidence for a Narrower Interpretation: The patent specification provides exemplary, preferred dimensions: "By way of example, the lateral width of the plug housing 14 is less than 1.75 inches, and preferably approximately 1.35 inches" (’794 Patent, col. 14:4-6). This explicit recitation of the claimed dimension as an example in the specification may support a strict, literal interpretation of the term.
VI. Other Allegations
- Indirect Infringement: The complaint does not contain allegations of indirect infringement.
- Willful Infringement: Plaintiff requests a determination that infringement has been willful in its prayer for relief (Compl., Prayer for Relief ¶C). The complaint alleges, "Upon information and belief," that the defendant had "actual or constructive knowledge" of Plaintiff's intellectual property rights (Compl. ¶20). The complaint does not plead specific facts detailing when or how Defendant became aware of the ’794 Patent.
VII. Analyst’s Conclusion: Key Questions for the Case
The resolution of this dispute may depend on the answers to two primary questions:
- A core issue will be one of evidentiary proof: Can Plaintiff demonstrate through measurement and testing that the accused "EGK-US" chargers possess a "longitudinal length" of less than 2.0 inches and a "width of the housing outer profile" of less than 1.75 inches, thereby satisfying the specific dimensional limitations added during the patent's reissue?
- A second key question will be one of claim scope: How will the court construe the functional limitation "having no interference with an adjacent receptacle"? The answer will determine the standard by which the accused products' physical shape and its interaction with standard multi-receptacle outlets are judged for infringement.