External power source to main battery power source switch
CA 2199214 C · Owner: Barkat, Shakil H. · Inventors: Black, Gregory Redmond; Barkat, Shakil H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A switching circuit (30) in a portable telephone connects a gate of a field-effect transistor (Q1) to a voltage below the transistor's gate threshold voltage when the voltage at a first power source terminal (B) falls below a threshold voltage, thus disconnecting the first power source terminal (B) from a portable telephone power input terminal (B+) and connecting a second power source terminal (A) to the power input terminal (B+). The threshold voltage is set at a voltage above the minimum supply voltage of the portable telephone. The first power source terminal may be connected to a main battery and the second power source terminal may be connected to an adapter such as a battery …
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 March 5, 1997 and granted May 16, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 5, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 5, 2019.
- 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.