Switching power supply for microwave oven
CA 2029230 C · Owner: Yoshioka, Hitoshi · Inventors: Fujishima, Kunihiro; Yoshioka, Hitoshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
of Disclosure, The present invention relates to a switching power suplly for microwave oven in which a DC power is changed to a pulse by means of a switching element coupled to a primary winding of an inverter transformer to supply the power to a high frequency oscillator (hereinafter referred to as a magnetron) coupled to a secondary winding. A reference voltage is set lower than an ordinary state from the time of turning on until the oscillation of the magnetron starts. Accordingly a power supplied from the secondary winding of the inverter transformer to the magnetron is set low. The reference voltage increases when the oscillation of magnetron starts and the same also returns to the …
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 2, 1990 and granted January 5, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 2, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 2, 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.