DCT
1:23-cv-01407
Sonrai Memory Ltd v. Micron Technology, Inc.
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Sonrai Memory Ltd. (Ireland)
- Defendant: Micron Technology, Inc. (Delaware)
- Plaintiff’s Counsel: Russ August & Kabat
- Case Identification: 6:22-cv-00855, W.D. Tex., 08/16/2022
- Venue Allegations: Plaintiff alleges venue is proper because Defendant Micron Technology, Inc. has a regular and established place of business in the district and has allegedly committed acts of infringement there.
- Core Dispute: Plaintiff alleges that Defendant’s Solid-State Drives (SSDs) and NAND Flash chips infringe two patents related to portable memory architecture and on-chip voltage regulation circuitry.
- Technical Context: The technology at issue concerns both the high-level architecture of portable data storage devices and the low-level semiconductor circuits used to power non-volatile memory.
- Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the asserted patents.
Case Timeline
| Date | Event |
|---|---|
| 2002-10-25 | U.S. Patent No. 6,724,241 Priority Date |
| 2003-02-11 | U.S. Patent No. 6,920,527 Priority Date |
| 2004-04-20 | U.S. Patent No. 6,724,241 Issued |
| 2005-07-19 | U.S. Patent No. 6,920,527 Issued |
| 2022-08-16 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,920,527, "Portable RAM drive," Issued July 19, 2005
The Invention Explained
- Problem Addressed: The patent describes a market where portable storage mediums like floppy disks and memory sticks were slow compared to a computer's internal random access memory (RAM) (’527 Patent, col. 1:28-34). This performance gap created a bottleneck for users accessing data on portable devices.
- The Patented Solution: The invention proposes a hybrid portable memory device that contains both non-volatile memory (for persistent data storage) and faster volatile memory (RAM). When the device is connected to a computer, data is copied from the non-volatile memory to the volatile memory, allowing the computer to access it at higher speeds ('527 Patent, col. 2:45-55). To prevent data loss upon disconnection, an internal power source (e.g., a capacitor or battery) provides enough power to write any changes from the volatile memory back to the non-volatile memory ('527 Patent, col. 2:54-62). Figure 4 illustrates this architecture, showing a memory controller chip managing data flow between the volatile memory, non-volatile memory, and the USB connection.
- Technical Importance: The described architecture aimed to combine the speed benefits of RAM with the portability and data persistence of non-volatile flash memory, addressing a key performance limitation of early-generation portable storage.
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶10).
- Essential elements of Claim 1:
- A portable memory apparatus comprising a housing.
- A memory controller comprised in the housing.
- A volatile memory coupled to the memory controller.
- A non-volatile memory coupled to the memory controller.
- A connector to couple the apparatus to a computer system.
- Wherein, upon connection, the memory controller "copies data from said non-volatile memory to said volatile memory."
- And wherein the computer system "accesses said data in said volatile memory through said connector."
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 6,724,241, "Variable charge pump circuit with dynamic load," Issued April 20, 2004
The Invention Explained
- Problem Addressed: The patent’s background explains that memory chips require high internal voltages for operations like programming and erasing, which are often generated by on-chip "charge pump" circuits. A problem with conventional charge pumps is that they can produce an unstable output voltage with significant "ripple" or "overshoot," especially when designed to supply multiple different voltage levels (’241 Patent, col. 2:4-28).
- The Patented Solution: The invention is a charge pump circuit designed to minimize this voltage ripple. It achieves this by incorporating a "plurality of loads" and a "load selector means" ('241 Patent, col. 3:7-14). The selector dynamically connects an appropriate load to the pump's output based on the desired target voltage. This matching of the load to the pump's operating condition stabilizes the output voltage, reducing inefficient and potentially harmful overshoots ('241 Patent, col. 4:51-56). Figure 3 shows a schematic of the circuit, including a pumping circuit (300), multiple loads (Load A, B, C), and switches (320, 324, 328) that act as the selector.
- Technical Importance: This technology provides a method for generating more stable and efficient on-chip high voltages, a fundamental requirement for the reliable operation of non-volatile memories like NAND Flash.
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶16).
- Essential elements of Claim 1:
- A charge pump circuit for generating a charge pump voltage with minimal ripples.
- A "pumping circuit" comprising one or more stages to receive a supply voltage and generate pump voltages.
- A "plurality of loads" that are selectively coupleable to the output of the pumping circuit, with each load associated with a specific pump voltage.
- A "load selector means" for selectively coupling a load to the output.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- For the ’527 Patent: A range of Micron-branded and Crucial-branded Solid-State Drives (SSDs), including NVMe and SATA models such as the 9300 SSD, 7450 SSD, and Crucial P5 Plus (Compl. ¶9).
- For the ’241 Patent: Micron's 176L 3D NAND Flash chips and other products containing flash chips with "substantially similar charge pumps" (Compl. ¶15).
Functionality and Market Context
- The accused SSDs are high-performance data storage devices used in computers and servers. Functionally, they use non-volatile NAND flash memory for long-term data storage and typically include a small amount of volatile DRAM memory that operates as a high-speed cache, managed by an onboard controller.
- The accused NAND flash chips are the core memory components within the accused SSDs and other electronic devices. The complaint alleges these chips contain charge pump circuitry to generate the various voltages needed for reading, writing, and erasing data from the memory cells (Compl. ¶16).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint references, but does not include, claim chart exhibits. The following tables summarize the infringement allegations based on the asserted claims and the general functionality of the accused product categories identified in the complaint.
’527 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A portable memory apparatus, comprising: a housing; | The physical enclosure or casing of the accused SSDs. | ¶9 | col. 2:41 |
| a memory controller comprised in the housing; | The controller chip within the accused SSDs that manages data flow and memory operations. | ¶9 | col. 2:60-62 |
| a volatile memory coupled to said memory controller...; | The DRAM cache memory used within the accused SSDs for high-speed temporary data storage. | ¶9 | col. 2:62-63 |
| a non-volatile memory coupled to said memory controller...; | The NAND flash memory chips used within the accused SSDs for persistent data storage. | ¶9 | col. 2:63-64 |
| a connector positioned on the housing...couples said portable memory apparatus to a computer system; | The SATA or NVMe interface on the accused SSDs that connects the drive to a host computer system. | ¶9 | col. 2:45-49 |
| ...said memory controller chip copies data from said non-volatile memory to said volatile memory,... | The process, managed by the SSD controller, of loading data from the NAND flash into the DRAM cache for faster access by the host. | ¶9 | col. 2:51-55 |
| ...said computer system accesses said data in said volatile memory through said connector. | The host computer system reading and writing data to the SSD's DRAM cache via the SATA/NVMe connector. | ¶9 | col. 2:51-55 |
- Identified Points of Contention:
- Scope Questions: A central question may be whether the standard caching algorithms used in modern SSDs for performance optimization meet the claim limitation "copies data from said non-volatile memory to said volatile memory." Defendant may argue that caching frequently-accessed data is functionally different from the broader data transfer process described in the patent.
- Technical Questions: The analysis may focus on how and when the accused SSDs transfer data between their non-volatile and volatile memory. The court may need to determine if this process is initiated "when said connector couples said portable memory apparatus to said computer system," as Claim 1 requires, or if it is a continuous, dynamic process driven by usage patterns.
’241 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a) a pumping circuit comprising one or more stages operable to receive a supply voltage and generate a selected one of a plurality of pump voltages; | The internal voltage-boosting circuitry within the accused Micron NAND flash chips used to generate high voltages for memory operations. | ¶15 | col. 3:64-4:4 |
| b) a plurality of loads selectively coupleable to an output of the pumping circuit, each load associated with a specific pump voltage; and | Multiple, distinct electrical loads (e.g., capacitors or current sinkers) allegedly present within the charge pump of the accused chips. | ¶15 | col. 4:35-38 |
| c) a load selector means for selectively coupling a load associated with a specific pump voltage to the output of said pumping circuit. | Control logic and switching transistors within the accused charge pump that allegedly select and connect one of the plural loads to the output. | ¶15 | col. 3:12-14 |
- Identified Points of Contention:
- Scope Questions: The term "load selector means" is a means-plus-function limitation under 35 U.S.C. § 112(f). Its scope is not limitless but is confined to the corresponding structures disclosed in the specification (and their equivalents). This raises the question of whether the accused circuits contain the specific switch-based structures shown in the '241 patent or legally equivalent structures.
- Technical Questions: The core of the dispute will be evidentiary. Infringement will depend on a detailed, circuit-level analysis of the accused Micron flash chips to determine if they actually implement a charge pump with a "plurality of loads" and a "load selector means" that functions in the manner claimed. The complaint's high-level allegations do not provide this evidence.
V. Key Claim Terms for Construction
For the ’527 Patent:
- The Term: "copies data from said non-volatile memory to said volatile memory"
- Context and Importance: This term is critical because it defines the core data transfer action that allegedly occurs upon connection. The viability of the infringement case against standard SSDs will depend on whether their caching operations fall within the scope of this term.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states the purpose of the transfer is to provide "faster access by the computer system" ('527 Patent, col. 2:53-55), which could support an argument that any transfer for performance enhancement, such as caching, is covered.
- Evidence for a Narrower Interpretation: A defendant might argue that the claim implies a more discrete, complete transfer event upon connection, rather than the continuous and dynamic caching process used in modern SSDs, which moves small blocks of data based on access patterns rather than connection events alone.
For the ’241 Patent:
- The Term: "load selector means"
- Context and Importance: This is a means-plus-function term, and its construction will define the specific circuitry that the accused products must contain to infringe. Practitioners may focus on this term because its scope is strictly limited by the patent's disclosure, making it a common point of non-infringement defense.
- Intrinsic Evidence for Interpretation:
- Function: "selectively coupling a load associated with a specific pump voltage to the output of said pumping circuit" ('241 Patent, col. 8:26-29).
- Corresponding Structure (Narrower Interpretation): The specification discloses the structure as a set of switches (320, 324, 328), such as NMOS transistors, each controlled by a respective control signal (EN_A, EN_B, EN_C) that enables connection of a specific load to the output ('241 Patent, col. 4:40-56; Fig. 3). The infringement analysis will be limited to this structure and its structural equivalents.
VI. Other Allegations
- Indirect Infringement: The complaint makes a boilerplate allegation of "direct and indirect infringement" (Compl. ¶6) but does not plead specific facts to support the knowledge and intent elements required for induced or contributory infringement, such as alleging that Micron's manuals instruct users in an infringing manner.
- Willful Infringement: The complaint does not explicitly allege willful infringement or plead facts suggesting Micron had pre-suit knowledge of the patents. It does request a finding of an "exceptional case" to recover attorneys' fees under 35 U.S.C. § 285 (Compl. p. 6, ¶e).
VII. Analyst’s Conclusion: Key Questions for the Case
A central issue for the ’527 patent will be one of functional scope: Does the dynamic, performance-optimizing caching mechanism of a modern SSD perform the same function as the "copies data" step recited in Claim 1, which the patent describes as an operation to make data available for "faster access" upon connection?
For the ’241 patent, the case will likely turn on claim construction and evidence: As the "load selector means" limitation will be construed narrowly to cover the specific switch-and-control-signal structure in the patent, a key question will be whether discovery of Micron's proprietary circuit designs reveals a structurally identical or equivalent system for selecting from a plurality of loads to stabilize voltage.