Method and apparatus for modulating hid ballast operating frequency using dc bus ripple voltage
CA 2406591 C · Owner: Osram Sylvania Inc. · Inventors: Trestman, Grigoriy A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus and method to implement an electronic ballast for a high intensity discharge lamp having AC lamp current centered at approximately 300 kHz minimizes the ballast cost and utilizes modulation of the lamp current to avoid acoustic resonance. In order to minimize the number of additional components providing the modulation function the ripple voltage produced by PFC circuit is fed through a capacitor to a FREQUENCY SET input of an inverter controller. The value of the capacitor can be chosen to produce the desired modulation range.
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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 October 4, 2002 and granted September 27, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 4, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 4, 2024.
- 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
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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.