Patents by Inventor Clarita Poon
Clarita Poon 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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Publication number: 20160081153Abstract: An LED lamp comprises one or more LEDs and an LED driver receiving an input signal from a dimmer switch indicative of an amount of dimming for the LED lamp. The LED driver controls regulated current through the one or more LEDs based on the input signal such that an output light intensity of the one or more LEDs substantially corresponds to the amount of dimming for the LED lamp. A regulated output provides operating power for the LED driver. A controller regulates the regulated output to power the LED driver. The controller selects a power source for charging the regulated output from two or more power sources, and the regulated output is charged using the power source selected by the controller.Type: ApplicationFiled: September 15, 2014Publication date: March 17, 2016Inventors: Chuanyang Wang, Chenglong Zhang, Nan Shi, Clarita Poon, Guang Feng
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Patent number: 9071147Abstract: The embodiments herein describe a power converter including a controller that estimates input current of the power converter. The controller estimates the input current without explicitly sensing the input current. The estimated input current can be used in various applications such as regulating power factor and total harmonic distortion as well as estimating current required to maintain proper operation of a dimmer switch in light emitting diode lamp systems.Type: GrantFiled: February 19, 2013Date of Patent: June 30, 2015Assignee: Dialog Semiconductor Inc.Inventors: Guang Feng, Xiaoyan Wang, Liang Yan, Chuanyang Wang, Clarita Poon
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Patent number: 8995150Abstract: The embodiments disclosed herein describe a method of a controller to maintain a substantially constant average output current at the output of a switching power converter. In one embodiment, the controller uses a regulation voltage that corresponds to the primary peak current regulation level to regulate the average output current.Type: GrantFiled: December 5, 2012Date of Patent: March 31, 2015Assignee: Dialog Semiconductor Inc.Inventors: Liang Yan, John William Kesterson, Xiaoyan Wang, Guang Feng, Clarita Poon
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Publication number: 20140233269Abstract: The embodiments herein describe a power converter including a controller that estimates input current of the power converter. The controller estimates the input current without explicitly sensing the input current. The estimated input current can be used in various applications such as regulating power factor and total harmonic distortion as well as estimating current required to maintain proper operation of a dimmer switch in light emitting diode lamp systems.Type: ApplicationFiled: February 19, 2013Publication date: August 21, 2014Inventors: Guang Feng, Xiaoyan Wang, Liang Yan, Chuanyang Wang, Clarita Poon
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Publication number: 20140153292Abstract: The embodiments disclosed herein describe a method of a controller to maintain a substantially constant average output current at the output of a switching power converter. In one embodiment, the controller uses a regulation voltage that corresponds to the primary peak current regulation level to regulate the average output current.Type: ApplicationFiled: December 5, 2012Publication date: June 5, 2014Applicant: IWATT INC.Inventors: Liang Yan, John William Kesterson, Xiaoyan Wang, Guang Feng, Clarita Poon
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Publication number: 20130249437Abstract: A dimming controller for an LED lamp controls dimming using an adaptive filter to reduce or eliminate perceivable flickering and to provide smooth transitions during active dimming. During stable conditions, the adaptive filter operates with a relatively narrow bandwidth to filter noise that may lead to perceivable flickering. During active or startup conditions, the adaptive mapping filter operates with a high bandwidth to provide a quick response to the dimmer switch.Type: ApplicationFiled: February 8, 2013Publication date: September 26, 2013Applicant: iWatt Inc.Inventors: Xiaoyan Wang, John William Kesterson, Clarita Poon, Liang Yan
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Patent number: 8199539Abstract: In a switching power converter, PWM mode and PFM mode are separated into two independent control sections with the control voltage range in each control section determined independently. Each of the PWM and PFM modulation modes cannot operate continuously beyond its boundaries, thereby forming a control gap between the two control sections within which no continuous operation is allowed. In order to supply a load condition within the control gap, the power supply operates at the two boundaries of the control gap. Transition between PWM and PFM modes occurs fast, with low output voltage ripple. No limitation needs to be imposed on the control voltage range in each of the PWM and PFM control sections, because the control parameters in the PWM and PFM control sections need not be matched to one another, due to separation of the PWM and PFM modes by the control gap.Type: GrantFiled: August 4, 2011Date of Patent: June 12, 2012Assignee: iWatt Inc.Inventors: Xiaoyan Wang, Liang Yan, Junjie Zheng, John William Kesterson, Clarita Poon
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Patent number: 8199537Abstract: A switching power converter detects low load conditions based on the ratio of a first peak current value for peak current switching in constant voltage regulation mode to a second peak current value for peak current switching in constant current regulation mode. The power supply load is considered to have a low load if the ratio is lower than a predetermined threshold. Once a low load condition is detected, the switching frequency of the switching power converter is reduced to a level that minimizes switching loss in the power converter. In addition, the switching power converter also adjusts the switching frequency according to the sensed input line voltage. An offset is added to the switching period to reduce the switching frequency of the switching power converter, as the input line voltage is increased.Type: GrantFiled: February 19, 2009Date of Patent: June 12, 2012Assignee: iWatt Inc.Inventors: Liang Yan, Xiaoyan Wang, Jun Zheng, Junjie Zheng, Clarita Poon
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Publication number: 20110286248Abstract: In a switching power converter, PWM mode and PFM mode are separated into two independent control sections with the control voltage range in each control section determined independently. Each of the PWM and PFM modulation modes cannot operate continuously beyond its boundaries, thereby forming a control gap between the two control sections within which no continuous operation is allowed. In order to supply a load condition within the control gap, the power supply operates at the two boundaries of the control gap. Transition between PWM and PFM modes occurs fast, with low output voltage ripple. No limitation needs to be imposed on the control voltage range in each of the PWM and PFM control sections, because the control parameters in the PWM and PFM control sections need not be matched to one another, due to separation of the PWM and PFM modes by the control gap.Type: ApplicationFiled: August 4, 2011Publication date: November 24, 2011Applicant: IWATT INC.Inventors: Xiaoyan Wang, Liang Yan, Junjie Zheng, John William Kesterson, Clarita Poon
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Patent number: 8049481Abstract: Adaptive multi-mode digital control schemes that improve the light-load efficiency (and thus the overall average efficiency) in switch-mode power converters without causing performance issues such as audible noises or excessive voltage ripples. Embodiments include a switch-mode power converter that reduces current in the power converter using a second pulse-width-modulation (PWM) mode before reaching switching frequencies that generate audible noises. As the load across the output of the power converter is reduced, the power converter transitions from a first PWM mode in high load conditions to a first pulse-frequency-modulation (PFM) mode, then to a second PWM mode, and finally to a second PFM mode. During the second PFM mode, the switching frequency is dropped to audible frequency levels. Current in the power converter, however, is reduced in the second PWM mode before transitioning to the second PFM mode.Type: GrantFiled: October 29, 2009Date of Patent: November 1, 2011Assignee: iWatt Inc.Inventors: Yong Li, Carrie Seim, Junjie Zheng, John W. Kesterson, Liang Yan, Clarita Poon, Fuqiang Shi
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Patent number: 8018743Abstract: In a switching power converter, PWM mode and PFM mode are separated into two independent control sections with the control voltage range in each control section determined independently. Each of the PWM and PFM modulation modes cannot operate continuously beyond its boundaries, thereby forming a control gap between the two control sections within which no continuous operation is allowed. In order to supply a load condition within the control gap, the power supply operates at the two boundaries of the control gap. Transition between PWM and PFM modes occurs fast, with low output voltage ripple. No limitation needs to be imposed on the control voltage range in each of the PWM and PFM control sections, because the control parameters in the PWM and PFM control sections need not be matched to one another, due to separation of the PWM and PFM modes by the control gap.Type: GrantFiled: March 5, 2009Date of Patent: September 13, 2011Assignee: iWatt Inc.Inventors: Xiaoyan Wang, Liang Yan, Junjie Zheng, John William Kesterson, Clarita Poon
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Publication number: 20100225293Abstract: In a switching power converter, PWM mode and PFM mode are separated into two independent control sections with the control voltage range in each control section determined independently. Each of the PWM and PFM modulation modes cannot operate continuously beyond its boundaries, thereby forming a control gap between the two control sections within which no continuous operation is allowed. In order to supply a load condition within the control gap, the power supply operates at the two boundaries of the control gap. Transition between PWM and PFM modes occurs fast, with low output voltage ripple. No limitation needs to be imposed on the control voltage range in each of the PWM and PFM control sections, because the control parameters in the PWM and PFM control sections need not be matched to one another, due to separation of the PWM and PFM modes by the control gap.Type: ApplicationFiled: March 5, 2009Publication date: September 9, 2010Applicant: IWATT INC.Inventors: Xiaoyan Wang, Liang Yan, Junjie Zheng, John William Kesterson, Clarita Poon
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Publication number: 20100208500Abstract: A switching power converter detects low load conditions based on the ratio of a first peak current value for peak current switching in constant voltage regulation mode to a second peak current value for peak current switching in constant current regulation mode. The power supply load is considered to have a low load if the ratio is lower than a predetermined threshold. Once a low load condition is detected, the switching frequency of the switching power converter is reduced to a level that minimizes switching loss in the power converter. In addition, the switching power converter also adjusts the switching frequency according to the sensed input line voltage. An offset is added to the switching period to reduce the switching frequency of the switching power converter, as the input line voltage is increased.Type: ApplicationFiled: February 19, 2009Publication date: August 19, 2010Applicant: IWATT INC.Inventors: Liang Yan, Xiaoyan Wang, Jun Zheng, Junjie Zheng, Clarita Poon
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Publication number: 20100164455Abstract: Adaptive multi-mode digital control schemes that improve the light-load efficiency (and thus the overall average efficiency) in switch-mode power converters without causing performance issues such as audible noises or excessive voltage ripples. Embodiments include a switch-mode power converter that reduces current in the power converter using a second pulse-width-modulation (PWM) mode before reaching switching frequencies that generate audible noises. As the load across the output of the power converter is reduced, the power converter transitions from a first PWM mode in high load conditions to a first pulse-frequency-modulation (PFM) mode, then to a second PWM mode, and finally to a second PFM mode. During the second PFM mode, the switching frequency is dropped to audible frequency levels. Current in the power converter, however, is reduced in the second PWM mode before transitioning to the second PFM mode.Type: ApplicationFiled: October 29, 2009Publication date: July 1, 2010Applicant: IWATT INC.Inventors: Yong Li, Carrie Seim, Junjie Zheng, John W. Kesterson, Liang Yan, Clarita Poon, Fuqiang Shi