Background
Chengdu Chip System Co. is the holder of an invention patent on a power-management chip, with claim 1 directed to a circuit architecture incorporating a pulse-signal generation feature. Power-management chips are central components in modern electronics — especially for new-energy vehicles, energy-storage systems, and industrial power applications — and the patent in suit covers a particular technical approach to managing power conversion and regulation.
Chengdu Chip alleged that Mao Tech (Shenzhen) Co. manufactured, offered for sale, and sold a competing power-management chip that infringed the patent. The first-instance court concluded that the accused chip’s circuit module was equivalent to the claimed pulse-signal-generation feature: same means, same function, same effect. The first-instance court found infringement and awarded approximately RMB 1.2 million (about US$170,000) in damages plus reasonable enforcement costs. Mao Tech appealed to the Supreme People’s Court IP Tribunal.
The Court’s Holding
The Supreme People’s Court reversed the first-instance judgment. The IP Tribunal held that the accused chip’s circuit module differed from the patented pulse-signal-generation feature on all three doctrine-of-equivalents prongs:
(1) Means (手段). The patented feature implemented pulse-signal generation through a specific arrangement of logic-circuit elements. The accused chip used a different circuit architecture to perform a related function. The means of achieving the result were not interchangeable.
(2) Function (功能). The patented feature’s specific function within the broader power-management chip was not performed by the accused chip’s corresponding module. The accused module played a different role in the overall power-management workflow.
(3) Effect (效果). The technical effect generated by the patented feature was not present in the accused chip; the accused chip achieved its overall power-management purpose through a different sequence of operations with different intermediate effects.
Because the accused module was not identical to and not equivalent to the patented pulse-signal-generation feature, the accused chip lacked an essential element of claim 1 and did not fall within the scope of protection. The IP Tribunal vacated the first-instance judgment and dismissed Chengdu Chip’s claims.
The Tribunal emphasized two points of broader significance for logic-circuit and electrical-engineering patents. First, in patents directed to logic-circuit features, the means/function/effect analysis must be performed at the level of the specific circuit-element arrangement, not at the level of high-level functional description. Logic circuits that perform similar high-level operations through different element arrangements are not automatically equivalent. Second, the Tribunal cautioned against expansion of the doctrine of equivalents in fast-moving technology fields like power-management semiconductors: protecting genuine innovation is the goal, but improper expansion of equivalents stifles competition and downstream improvement.
Key Takeaways
- The SPC IP Tribunal continues to take a careful, narrowing line on the doctrine of equivalents in logic-circuit and electrical-engineering patents. Patentees should not assume that high-level functional similarity equates to means/function/effect equivalence.
- The means prong is examined at the specific circuit-element-arrangement level, not at an abstracted functional level. This favors generic and follow-on chip designers who can implement comparable high-level functions through different circuit architectures.
- For power-management semiconductors specifically — a strategic technology for new-energy vehicles, storage, and industrial power — the Tribunal signals that competitive design-arounds remain available where the design genuinely uses different circuit means.
- Patentees prosecuting logic-circuit inventions should draft claims at multiple levels of generality: high-level functional claims for breadth, plus circuit-architecture-level claims for solid infringement positions, and method claims tied to specific signal sequences.
- The case is one of ten 2025 IP typical cases designated by the SPC, signaling national-level guidance value beyond the parties to this dispute.
Why It Matters
China is the world’s largest producer and consumer of semiconductors, and power-management chips in particular are critical for the new-energy-vehicle and energy-storage industries that the Chinese government has identified as strategic priorities. The Supreme People’s Court’s elaboration of how the doctrine of equivalents applies to chip patents directly affects competitive dynamics in these industries.
The decision continues a trend across recent SPC IP-Tribunal cases: rigorous, narrow application of equivalents in technology areas where claim drafting is challenging and where overly broad equivalents would suppress competition and follow-on innovation. The Tribunal’s guidance is largely favorable to defendants who can show that their accused circuits use genuinely different means, even where the high-level result is similar. For chip-design houses and integrated-device manufacturers operating in China, the practical lesson is to invest in design-around analysis at the circuit-architecture level, not just at the functional level.
For patentees, the lesson is on the prosecution side: claim drafting in logic-circuit patents must include claims at multiple levels of generality to retain meaningful scope. Pure high-level functional claims will frequently fail under the SPC’s narrow equivalents analysis when defendants implement different specific architectures. The 2025 designation as a typical IP case ensures this guidance will be applied across China’s specialized IP courts and the SPC’s IP Tribunal in subsequent cases.