Patents by Inventor David M. Garner
David M. Garner 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: 11917030Abstract: A push notification distribution system centralizes the management and delivery of push notifications to applications executing on electronic devices. Registration requests to register applications for push notifications may be aggregated and sent as an aggregated registration request. The delivery priority of push notifications may be managed according to specified preferences. Upon receiving a push notification intended for an electronic device, a delivery priority of the push notification may be changed if an application identifier associated with the push notification is found on a list of application identifiers with designed delivery priorities.Type: GrantFiled: March 26, 2021Date of Patent: February 27, 2024Assignee: Apple Inc.Inventors: Huan He, Jonathon Sodos, Nicholas J. Circosta, Sean Geiger, Nelson M. Leduc, Cisto Cyriac, Matthew E. Shepherd, David A. Schaefgen, Elliot T. Garner, Jose A. Lozano Hinojosa, Mursalin Akon, Robert D. Butler, Xudong Liu
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Patent number: 8411468Abstract: We describe a resonant discontinuous power converter including a magnetic energy storage device, and a bipolar junction transistor (BJT) switch having a collector terminal coupled to repetitively switch power from the input on and off to said magnetic energy storage device such that power is transferred from the input to the output. During an off-period of said BJT switch a voltage on said magnetic energy storage device and on said collector terminal of said BJT is at least partially resonant. The power converter includes a voltage clamping circuit to clamp a base voltage on a base terminal of said BJT during a resonant portion of said off-period to limit an excursion of a collector voltage on said collector terminal of said BJT towards or beyond an emitter voltage of said BJT during said resonant portion of said off-period, in particular to inhibit reverse bias of a base emitter junction of the transistor.Type: GrantFiled: April 25, 2008Date of Patent: April 2, 2013Assignee: Cambridge Semiconductor LimitedInventors: Vinod A. Lalithambika, Paul Ryan, David M. Garner, Russell Jacques
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Patent number: 8022744Abstract: Embodiments include a signal generator circuit for generating a time-varying signal, comprising capacitive element; FET to supply to or from the capacitive element a current matched to the FET drain current; a bias voltage generator to provide a bias voltage to the FET gate, wherein: the capacitances per unit area of the capacitive element and the FET gate are matched; the bias voltage is substantially equal to a sum of a first voltage substantially proportional to a reference voltage and a second voltage substantially proportional to temperature; the FET source-gate voltage substantially equal to the sum of the bias voltage and the gate threshold voltage, the bias voltage and a further voltage approximately equal to the gate threshold voltage summed to determine the FET source-gate voltage, the circuit to control a time period of the time-varying signal dependent on the current supply.Type: GrantFiled: October 3, 2008Date of Patent: September 20, 2011Assignee: Cambridge Semiconductor LimitedInventors: Vinod A. Lalithambika, David M. Garner
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Patent number: 7944722Abstract: This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point by fitting a tangent to a portion of a power transformer voltage waveform, and samples the voltage waveform at the knee point to determine the SMPS output voltage. In preferred embodiments this technique is implemented using a decaying peak detector, providing a timing signal indicating detection of the knee point. Sample/hold and error amplifier circuits may be employed to achieve output voltage regulation.Type: GrantFiled: March 17, 2009Date of Patent: May 17, 2011Assignee: Cambridge Semiconductor LimitedInventors: David R. Coulson, Johan Piper, David M. Garner
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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: 7782083Abstract: Techniques for programming trimming circuitry of a power integrated circuit without the need for separate programming pins are disclosed. According to a first aspect of the invention, there is provided a power supply controller IC with internal circuitry, a plurality of external connections, the IC further comprising trimming circuitry with no external connections to the IC other than via shared ones of the external connections. The shared external connections can comprise a first connection comprising a data input for receiving data for programming the trimming circuitry, and a second, different connection comprising a select input to select between a data receiving mode for receiving data from the data input and a programming mode for programming the trimming circuitry using the received data.Type: GrantFiled: December 14, 2006Date of Patent: August 24, 2010Assignee: Cambridge Semiconductor LimitedInventors: Vinod A. Lalithambika, David M. Garner, David Robert Coulson, Zahid Ansari
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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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Publication number: 20100091525Abstract: We describe a resonant discontinuous power converter including a magnetic energy storage device, and a bipolar junction transistor (BJT) switch having a collector terminal coupled to repetitively switch power from the input on and off to said magnetic energy storage device such that power is transferred from the input to the output. During an off-period of said BJT switch a voltage on said magnetic energy storage device and on said collector terminal of said BJT is at least partially resonant. The power converter includes a voltage clamping circuit to clamp a base voltage on a base terminal of said BJT during a resonant portion of said off-period to limit an excursion of a collector voltage on said collector terminal of said BJT towards or beyond an emitter voltage of said BJT during said resonant portion of said off-period, in particular to inhibit reverse bias of a base emitter junction of the transistor.Type: ApplicationFiled: April 25, 2008Publication date: April 15, 2010Inventors: Vinod A. Lalithambika, Paul Ryan, David M. Garner, Russell Jacques
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Publication number: 20100085115Abstract: This invention generally relates to signal generation, clock signal generation and ramp signal generation, and trimming the temperature coefficient of a signal.Type: ApplicationFiled: October 3, 2008Publication date: April 8, 2010Inventors: Vinod A. Lalithambika, David M. Garner
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Publication number: 20090237960Abstract: This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point by fitting a tangent to a portion of a power transformer voltage waveform, and samples the voltage waveform at the knee point to determine the SMPS output voltage. In preferred embodiments this technique is implemented using a decaying peak detector, providing a timing signal indicating detection of the knee point. Sample/hold and error amplifier circuits may be employed to achieve output voltage regulation.Type: ApplicationFiled: March 17, 2009Publication date: September 24, 2009Applicant: Cambridge Semiconductor LimitedInventors: David Robert Coulson, Johan Piper, David M. Garner
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Patent number: 7583519Abstract: This invention relates to methods and apparatus for sensing the output current in a switch mode power supply (SMPS) using primary side sensing. We describe a module which senses a current in a primary winding of a transformer and a voltage on a primary or auxiliary winding of the transformer, and which includes a multiplier coupled to an output of a signal averager averaging a primary winding current and to an output of a timing signal generator using the sensed voltage to signal when a secondary winding is powering an output of the SMPS, to multiply an averaged current sense signal by a fraction of a total cycle period of said SMPS during which the secondary winding is providing power to provide a signal estimating an output current of the SMPS.Type: GrantFiled: January 22, 2008Date of Patent: September 1, 2009Assignee: Cambridge Semiconductor LimitedInventors: Johan Piper, David M. Garner, David Robert Coulson
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Patent number: 7567445Abstract: This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point by fitting a tangent to a portion of a power transformer voltage waveform, and samples the voltage waveform at the knee point to determine the SMPS output voltage. In preferred embodiments this technique is implemented using a decaying peak detector, providing a timing signal indicating detection of the knee point. Sample/hold and error amplifier circuits may be employed to achieve output voltage regulation.Type: GrantFiled: June 1, 2006Date of Patent: July 28, 2009Assignee: Cambridge Semiconductor LimitedInventors: David Robert Coulson, Johan Piper, David M. Garner
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Patent number: 7525823Abstract: Methods and apparatus for sensing the output current in a switch mode power supply (SMPS) using primary side sensing are described. A system includes a primary current sense input, a charge input to sense a charging time of an SMPS transformer; a discharge input to sense a discharging time of the transformer; at least one averager; and a calculator. The primary current is averaged by the averager over at least a switching cycle of the SMPS and the calculator estimates the output current of the SMPS using the averaged primary current, the charge signal and the discharge signal.Type: GrantFiled: July 21, 2006Date of Patent: April 28, 2009Assignee: Cambridge Semiconductor LimitedInventors: Johan Piper, David M. Garner
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Patent number: 7504815Abstract: We describe a switch mode power supply (SMPS) controller employing a combination of pulse frequency and pulse width modulation. The controller employs a “gear box” control scheme using two complementary control loops, one for real-time control of the SMPS using PFM and a second using a PWM control scheme which monitors the switching frequency and, at defined operating points, adjusts the pulse width up or down through a set of pre-determined values. This can be considered analogous to the gearbox of a motor vehicle with the SMPS pulse width, switching frequency and output power roughly corresponding to the vehicle's gear ratio, engine speed and road speed respectively.Type: GrantFiled: July 6, 2006Date of Patent: March 17, 2009Assignee: Cambridge Semiconductor LimitedInventors: Philip John Moyse, David Robert Coulson, Russell Jacques, David M. Garner
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Publication number: 20090040796Abstract: We describe a switching power converter comprising a bipolar switching device (BJT or IGBT) switching an inductive load, and including a closed-loop control system. The control system comprises a voltage sensing system to sense a voltage on a collector terminal of the switching device and provide a voltage sense signal; a controller; and a drive modulation system coupled to an output of the controller for modulating a drive to the control terminal of said bipolar switching device responsive to a controller control signal; wherein said controller is configured to monitor changes in the sensed voltage during a period when said switching device is switched on and to control said drive modulation system to control the degree of saturation of said bipolar switching device when the device is switched on and hence improve turn-off times.Type: ApplicationFiled: April 24, 2008Publication date: February 12, 2009Applicant: Cambridge Semiconductor LimitedInventors: Vinod A. Lalithambika, Paul Ryan, David M. Garner, Russell Jacques
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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: 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: 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: 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