Protection circuit for battery feed circuit
CA 1333189 C · Owner: Tojo, Toshiro · Inventors: Takato, Kenji; Yamamoto, Yuzo; Tojo, Toshiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A protection circuit for a battery feed circuit used in a switching system. The protection circuit is comprised of: a supervising circuit for detecting an abnormal current flowing through a battery feed resistor; and a voltage limiting circuit for clamping a voltage across the battery feed resistor when the abnormal current is detected. Further, a control circuit is employed for stopping an operational amplifier when the abnormal current is detected. The operational amplifier constitutes a conventional battery feed circuit and is connected, at the output thereof with the base of a battery feed transistor connected between a subscriber's line and the battery feed resistor.
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
- Granted November 22, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 22, 2011.
- 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.