Use of the word “circuit” generally connotes structure and avoids a usually undesirable means-plus-function construction, especially when accompanied by adjectival qualification or functional language describing its operation (e.g., a “soft start” circuit that “provides a signal instructing … “). The court paid lip service to the caution that “not just any adjectival qualification or functional language will suffice,” but cited only a dissenting opinion on the issue. A qualified “circuit” element therefore appears to be as close to a safe-harbor as you can get for avoiding a means-plus-function construction in electronic cases.
Background / Facts: The patents here relate to power supplies for electronic devices that are designed to alleviate electromagnetic interference and current flow problems associated with prior art power supplies. Although the patented technologies are applicable generally in the field of electronics, the present case focuses on their use in chargers for mobile phones. Among other features, the improved circuitry provides “soft-start” functionality for reducing inrush current. In this regard, the claims recite “a soft start circuit that provides a signal instructing said drive circuit to discontinue said drive signal when said magnitude of said oscillation signal is greater than a magnitude of said frequency variation signal.” Several issues were at play, from obviousness to remittitur to willfulness, but I found the means-plus-function discussion the most relevant for patent prosecution.
Issue(s): Whether the term “soft start circuit” should be construed in accordance with Section 112, ¶ 6 and limited to the structure described in the specification and its equivalents.
Holding(s): No. “We have previously held on several occasions that the term ‘circuit’ connotes structure.” (Several citations given.) Here, “[a]lthough the claim includes a functional description of the ‘soft start circuit,’ the claim does not include the word ‘means.’ Further, the claimed ‘soft start circuit’ performs a straightforward function when a simple test is met … The word ‘circuit’ in combination with such a clear and unambiguous description of the circuit’s operation weighs heavily in favor finding sufficient structure to avoid means-plus-function claiming.” The court was quick to dismiss the district court’s concern that one skilled in the art would not know the precise structures for a “soft start circuit” because it can be achieved in a variety of ways, cautioning that “we require only that the claim term be used in common parlance or by ordinarily skilled artisans to designate sufficiently definite structure, even if the term covers a broad class of structures.”