A tri-state switching amplifier
CA 2099260 C · Owner: Apogee Technology, Inc. · Inventors: Howatt, John R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A switching amplifier system which in one embodiment includes switching circuitry (25) responsive to a tri-state command signal for providing a power output from a power supply (27) which has amplitude levels, time durations, and polarities corresponding to the tri-state command signal for supply to a load (19) via a suitable filter (18). A further embodiment includes a linear amplifier (53), the switching circuitry responding to a fourth state command signal for actuating the linear amplifier to respond directly to an input signal when the amplitude of the input signal is below a selected level.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 8, 1991 and granted September 18, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 8, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 8, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.