Audio amplifier with phase modulated pulse width modulation
CA 2009775 C · Owner: Hand, Larry E. · Inventors: Santillano, Lee C.; Attwood, Brian E.; Hand, Larry E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention discloses a digital controlled switching circuit which comprises a dc power source a first switching, means connected to that power source and operable to provide a square wave output, a second switching means connected to receive the square wave output, a phase control means connected to control the switching of the second switching means at a phase angle relative to the square wave output which is a function of a control signal and a diode means, for controlling the polarities of the outputs of said second switching means to provide a phase modulated pulse width modulation thereof.
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 February 9, 1990 and granted December 6, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 9, 2012.
- 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.