Patents by Inventor Devarahandi Indika Mahesh de Silva
Devarahandi Indika Mahesh de Silva has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7830130Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A method of controlling a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said method comprising: sensing a primary winding signal during an on period of said switch, said primary winding signal representing a current in said primary winding; comparing said sensed primary winding signal with a threshold value; and controlling one or both of an on and off duration of said switch in response to said comparison.Type: GrantFiled: April 2, 2007Date of Patent: November 9, 2010Assignee: Cambridge Semiconductor LimitedInventors: Russell Jacques, Paul Ryan, Catriona McKay, Devarahandi Indika Mahesh de Silva, David M. Garner, Vinod A. Lalithambika
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Patent number: 7751208Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A controller for a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said controller having a primary sense input to sense a primary winding signal, said primary winding signal representing a voltage across said primary winding or across an additional winding coupled to said primary winding, and wherein said controller is configured to switch on said switch in response to detection of a reduction in a rate of change of said primary winding signal below a threshold, adjacent a substantially minimum value in an operational cycle of said sensed primary winding signal to convey power to said DC output.Type: GrantFiled: April 2, 2007Date of Patent: July 6, 2010Assignee: Cambridge Semiconductor LimitedInventors: Russell Jacques, Paul Ryan, Catriona McKay, Devarahandi Indika Mahesh de Silva, David M. Garner, Vinod A. Lalithambika
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Patent number: 7714554Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A method of controlling a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said method comprising: sensing a transformer signal, said transformer signal representing a voltage across a winding of said transformer or a resonant current in a winding of said transformer; calculating a resonance period of said RDFC from said sensed transformer signal; and controlling an off duration of said switch in response to said calculated resonance period such that a sub-harmonic oscillation in said resonant voltage across said primary winding is reduced.Type: GrantFiled: April 2, 2007Date of Patent: May 11, 2010Assignee: Cambridge Semiconductor LimitedInventors: Russell Jacques, Paul Ryan, Catriona McKay, Vinod A. Lalithambika, David M. Garner, Devarahandi Indika Mahesh de Silva
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Patent number: 7447049Abstract: This invention relates to SMPS controllers employing primary side sensing to detect a point of zero magnetic flux, at which the output voltage of the SMPS may be sampled accurately on the primary side. We describe a switch mode power supply (SMPS) controller for regulating the output voltage of an SMPS is response to a feedback signal from an auxilliary winding of a magnetic energy storage device forming part of an output circuit of the SMPS, the SMPS controller comprising: a reference level input to receive an output reference level signal; an input to receive said feedback signal, said feedback signal being responsive to a voltage on said auxilliary winding of said magnetic energy storage device; an integrator to integrate a difference between said feedback signal and a first fixed reference level signal; a first comparator to compare an output of said integrator with a second fixed reference level signal and to provide an output responsive to said comparison for regulating said SMPS output voltage.Type: GrantFiled: June 1, 2006Date of Patent: November 4, 2008Assignee: Cambridge Semiconductor LimitedInventors: David M. Garner, David Robert Coulson, Devarahandi Indika Mahesh de Silva, Jayaraman Kumar, Vinod A. Lalithambika
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Publication number: 20080239762Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A controller for a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said controller having a primary sense input to sense a primary winding signal, said primary winding signal representing a voltage across said primary winding or across an additional winding coupled to said primary winding, and wherein said controller is configured to switch on said switch in response to detection of a reduction in a rate of change of said primary winding signal below a threshold, adjacent a substantially minimum value in an operational cycle of said sensed primary winding signal to convey power to said DC output.Type: ApplicationFiled: April 2, 2007Publication date: October 2, 2008Inventors: Russell Jacques, Paul Ryan, Catriona McKay, Devarahandi Indika Mahesh de Silva, David M. Garner, Vinod A. Lalithambika
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Publication number: 20080239761Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A method of controlling a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said method comprising: sensing a transformer signal, said transformer signal representing a voltage across a winding of said transformer or a resonant current in a winding of said transformer; calculating a resonance period of said RDFC from said sensed transformer signal; and controlling an off duration of said switch in response to said calculated resonance period such that a sub-harmonic oscillation in said resonant voltage across said primary winding is reduced.Type: ApplicationFiled: April 2, 2007Publication date: October 2, 2008Inventors: Russell Jacques, Paul Ryan, Catriona McKay, Vinod A. Lalithambika, David M. Garner, Devarahandi Indika Mahesh de Silva
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Publication number: 20080239764Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). A method of controlling a resonant discontinuous forward converter (RDFC), said converter including a transformer with primary and secondary matched polarity windings and a switch to, in operation, cyclically switch DC power to said primary winding of said transformer, said converter further having a DC output coupled to said secondary winding of said converter, said method comprising: sensing a primary winding signal during an on period of said switch, said primary winding signal representing a current in said primary winding; comparing said sensed primary winding signal with a threshold value; and controlling one or both of an on and off duration of said switch in response to said comparison.Type: ApplicationFiled: April 2, 2007Publication date: October 2, 2008Inventors: Russell Jacques, Paul Ryan, Catriona McKay, Devarahandi Indika Mahesh de Silva, David M. Garner, Vinod A. Lalithambika
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Publication number: 20070274112Abstract: This invention relates to switch mode power supply (SMPS) controllers employing primary side sensing. We describe an (SMPS) controller which uses an area correlator to compare an area under a feedback signal waveform between a start point defined by said first timing signal and an end point defined by said second timing signal with a reference area. An output of the area correlator provides an error signal for regulating the SMPS output.Type: ApplicationFiled: June 1, 2006Publication date: November 29, 2007Inventors: Vinod A. Lalithambika, Devarahandi Indika Mahesh de Silva, Jayaraman Kumar, Gehan Amaratunga
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Publication number: 20070274107Abstract: This invention relates to SMPS controllers employing primary side sensing to detect a point of zero magnetic flux, at which the output voltage of the SMPS may be sampled accurately on the primary side. We describe a switch mode power supply (SMPS) controller for regulating the output voltage of an SMPS is response to a feedback signal from an auxilliary winding of a magnetic energy storage device forming part of an output circuit of the SMPS, the SMPS controller comprising: a reference level input to receive an output reference level signal; an input to receive said feedback signal, said feedback signal being responsive to a voltage on said auxilliary winding of said magnetic energy storage device; an integrator to integrate a difference between said feedback signal and a first fixed reference level signal; a first comparator to compare an output of said integrator with a second fixed reference level signal and to provide an output responsive to said comparison for regulating said SMPS output voltage.Type: ApplicationFiled: June 1, 2006Publication date: November 29, 2007Inventors: David M. Garner, David Robert Coulson, Devarahandi Indika Mahesh de Silva, Jayaraman Kumar, Vinod A. Lalithambika