Hildebrandt & Power Density Solutions v. Google — TPUv3 Patent Case Dismissed
Power Density Solutions and inventor James Hildebrandt sued Google in the Southern District of California alleging infringement of US6552901B2 by Google’s version 3 Tensor Processing Units. The case closed just 92 days after filing when plaintiffs voluntarily dismissed without prejudice before Google served an answer.
TPUv3 infringement claim exits before Google responds
On August 13, 2024, James Hildebrandt and Power Density Solutions, LLC filed suit against Google, LLC in the U.S. District Court for the Southern District of California, asserting infringement of U.S. Patent No. 6,552,901. The accused product is Google’s version 3 Tensor Processing Unit (TPUv3), a custom AI accelerator chip central to Google’s machine-learning infrastructure. The case was assigned Case No. 3:24-cv-01437 and handled by Weeks Nelson on the plaintiff side, with Paul Hastings, LLP retained by Google.
On November 12, 2024 — three months after filing — plaintiffs filed a Notice of Voluntary Dismissal under Federal Rule of Civil Procedure 41(a)(1)(A)(i). Because Google had not yet served an answer or a summary judgment motion, the dismissal was self-executing and required no court action. The court confirmed the dismissal without prejudice the following day. A without-prejudice dismissal means the claims are extinguished for now but plaintiffs retain the right to refile the same allegations, subject to applicable statutes of limitations.
A 92-day lifecycle ending before any substantive exchange is notable: it suggests the parties may have reached an early accommodation, or that plaintiffs reassessed their filing strategy after defendant retained a well-resourced litigation team from Paul Hastings. The without-prejudice posture keeps litigation optionality alive. The public record is silent on any settlement, license, or claim-mapping exercise that may have driven the early exit, and no financial terms are disclosed.
Filing to Dismissed without Prejudice in 92 days
92 days — resolved before any substantive pleading exchange
Dismissed without prejudice: what the Rule 41 exit means for both sides
Rule 41(a)(1)(A)(i): plaintiff’s absolute right to exit early
Under FRCP 41(a)(1)(A)(i), a plaintiff may voluntarily dismiss an action as of right — with no court approval needed — before the defendant serves an answer or summary judgment motion. The Ninth Circuit treats this as an ‘absolute right.’ Google had not yet answered, so the dismissal was self-executing and took effect upon filing. The court’s November 13 order merely confirmed the administrative close.
Self-executing dismissalWithout prejudice: the door to refiling stays open
A dismissal without prejudice does not adjudicate the merits. Power Density Solutions retains the right to refile claims based on US6552901B2 against Google, provided the statute of limitations (six years for patent infringement under 35 U.S.C. § 286) has not run on the accused acts. Plaintiffs face no claim-preclusion bar from this dismissal. Note: this is a court-confirmed without-prejudice dismissal — not an ambiguous voluntary dismissal where prejudice status is uncertain.
Refiling right preservedGoogle exits with no merits ruling — but risk lingers
Google secured a clean exit: no infringement finding, no claim construction, no invalidity ruling on US6552901B2. Paul Hastings’s six-attorney team never had to serve a formal response. However, because the dismissal is without prejudice, Google cannot treat this matter as closed. The TPUv3 — and successor TPU generations — remain potentially exposed to a refiled action asserting the same patent.
No merits adjudicationAI accelerator IP: early exits rarely signal the end
TPU architecture is strategic infrastructure for Google’s AI business. A without-prejudice dismissal in an accelerator-hardware patent case typically signals one of three scenarios: a licensing conversation is underway, the plaintiff is refining claim charts, or the parties have reached an undisclosed agreement. For competitors and licensees in the AI chip space, US6552901B2 remains an unlitigated-on-the-merits patent that could re-enter enforcement at any point.
Patent enforcement risk activeFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | James Hildebrandt | Individual | Patent holding entity — holder of US6552901B2, power-density and processing IPSearch in Eureka ↗ |
| Co-Plaintiff | Power Density Solutions, LLC | Company | Search in Eureka ↗ |
| Defendant | Google, LLC | Company | Google, LLC — developer of custom TPU AI accelerator hardwareSearch in Eureka ↗ |
| Plaintiff counsel | Gregory K. Nelson | Attorney | Counsel for James HildebrandtSearch in Eureka ↗ |
| Plaintiff counsel | Gregory N. Suhr | Attorney | Counsel for James HildebrandtSearch in Eureka ↗ |
| Plaintiff law firm | Weeks Nelson | Law Firm | Representing James HildebrandtSearch in Eureka ↗ |
| Defendant counsel | Ariell Bratton | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant counsel | Elizabeth L. Brann | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant counsel | Matthias A. Kamber | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant counsel | Robert Laurenzi | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant counsel | Robert W. Unikel | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant counsel | Sasha Vujcic | Attorney | Counsel for Google, LLCSearch in Eureka ↗ |
| Defendant law firm | Paul Hastings, LLP | Law Firm | Representing Google, LLCSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | California Southern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The court’s order confirms the dismissal arose under Rule 41(a)(1)(A)(i) — the self-executing provision triggered by Google’s failure to serve an answer. The without-prejudice designation is court-affirmed, not merely assumed. This means no merits of the infringement claim were assessed: validity, claim scope, and accused product mapping all remain open. For Power Density Solutions, the order preserves maximum flexibility; for Google, it provides procedural closure but no substantive protection against re-assertion of US6552901B2.
US6552901B2 — power density and processing unit architecture
U.S. Patent No. 6,552,901 (application number 09/974,335) is asserted by Power Density Solutions, LLC and inventor James Hildebrandt. The patent addresses power-density management in processing unit hardware — a design challenge that is acutely relevant to large-scale AI accelerators where thermal and power constraints directly limit computational throughput. The application pre-dates the modern deep-learning era, suggesting the core inventive concept may have broad applicability across evolving accelerator architectures.
Google’s TPUv3 was specifically identified as the accused product, making this patent strategically significant for any company designing or deploying custom AI inference and training hardware. As hyperscalers race to develop proprietary silicon — including TPU, Trainium, and similar designs — patents covering foundational power-density architecture acquire increasing commercial leverage. The absence of any prior claim construction or invalidity ruling means US6552901B2 enters any future proceeding with an untested but presumed-valid status under 35 U.S.C. § 282.
Should you run an FTO analysis against US6552901B2?
Any organisation designing custom AI accelerators, neural processing units, or high-density compute modules should treat US6552901B2 as an active FTO concern. The patent was asserted against Google’s TPUv3 — a product representing the state of the art in AI training hardware — and remains unlitigated on the merits. Hardware teams at semiconductor companies, cloud providers, and edge AI chip developers should verify whether their power-density architectures fall within the claim scope before tape-out or product launch.
PatSnap Eureka’s FTO Search Agent can map the claims of US6552901B2 against your product specifications and identify design-around opportunities or prior art that may affect validity. The platform also monitors new filings by Power Density Solutions, LLC so your legal team receives early warning if assertion activity resumes — giving you time to respond strategically rather than reactively.
Run a freedom-to-operate analysis on US6552901B2 to assess your product’s exposure
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What this case signals for the AI hardware IP landscape
A 92-day voluntary dismissal against Google’s TPUv3 raises questions that matter beyond this single docket.
Without-prejudice exits keep patent risk live for AI chip developers
Power Density Solutions retains full ability to refile against Google or assert US6552901B2 against other AI accelerator manufacturers. Companies building custom inference hardware — including hyperscalers and semiconductor vendors — should map their architectures against this patent before a new filing appears.
Early team size asymmetry is a common driver of pre-answer exits
Google deployed a six-lawyer team from Paul Hastings within the filing window. This level of early resourcing by a defendant can signal aggressive defence preparation and sometimes prompts plaintiffs to reassess litigation economics before spending is committed on both sides.
Hildebrandt v Google — key questions answered
The case was dismissed without prejudice on November 13, 2024. Plaintiffs filed a voluntary Notice of Dismissal under FRCP 41(a)(1)(A)(i) before Google served an answer, making the dismissal self-executing. No merits ruling was issued. Power Density Solutions retains the right to refile claims based on US6552901B2.
The asserted patent is US6552901B2 (application no. 09/974,335), held by Power Density Solutions, LLC and inventor James Hildebrandt. The accused product is Google’s version 3 Tensor Processing Unit (TPUv3), a custom AI accelerator chip. The patent relates to power-density architecture in processing unit hardware.
No. A dismissal without prejudice is not a merits victory for either party. It terminates the current action but does not adjudicate infringement, validity, or damages. The patent holder retains the right to refile within the statute of limitations. Google received no invalidity ruling or non-infringement finding from this dismissal.
FRCP 41(a)(1)(A)(i) gives a plaintiff the absolute right to voluntarily dismiss an action before the defendant serves an answer or a summary judgment motion. Because Google had not yet answered in this case, the dismissal was self-executing — it required no court approval and took immediate effect upon plaintiffs filing the notice on November 12, 2024.
Yes, subject to the six-year damages limitation under 35 U.S.C. § 286 and any applicable equitable defences. A without-prejudice dismissal imposes no claim-preclusion bar. Power Density Solutions could refile against TPUv3 or potentially assert US6552901B2 against newer TPU generations, depending on how the claims read on those architectures.
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