Patents by Inventor Towfiq CHOWDHURY
Towfiq CHOWDHURY 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: 10104731Abstract: A dimmable driver for an LED light fixture allows multiple types of dimmers to be used with the light fixture. The dimmable driver may be disconnected from one type of dimmer and subsequently connected to another type of dimmer without having to replace or otherwise adjust the driver for each dimmer. Multiple types of dimmers may be connected to dimmable driver at the same time and the dimmable driver may use dimming signals from one or several of these dimmers. In some embodiments, the dimmable driver is configured to accommodate a step dimmer, a 0-10 V dimmer, and a phase-cut dimmer. Other dimmers and dimming protocols may be accommodated by the dimmable driver in alternative embodiments. Such an arrangement maximizes flexibility for lighting specifiers, contractors, and distributors while minimizing potential errors, costs, delays, and obsolete inventory.Type: GrantFiled: December 8, 2015Date of Patent: October 16, 2018Assignee: ABL IP Holding LLCInventors: Feng-Kang Hu, Hangyang Wang, Feng Chen, Towfiq Chowdhury, Charles J. Spencer
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Patent number: 9867254Abstract: A dimmable LED lighting system includes first, second and third types of LED light sources, and an LED driver to control the supply of current on first, second and third channels, respectively to the first, second and third types of LED light sources. The first, second and third types of LED light sources are selected according to their spectral power distribution (SPD) curves. The selected SPD curves together model a dimming color curve that is characteristic of an incandescent light source when the first, second and third types of LED light sources are separately driven with current at predefined power ratios that correspond to dimming levels over a dimming region of the dimming color curve. The dimmable LED lighting system can have a color rendering index Ra greater than 80 over the dimming region.Type: GrantFiled: October 31, 2014Date of Patent: January 9, 2018Assignee: ABL IP Holding LLCInventors: Raghuram L. V. Petluri, Towfiq Chowdhury
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Patent number: 9860951Abstract: A lighting system includes various LED boards. The LED boards are connected to a power source via an LED driver that regulates power from the power source to the LED boards. The LED driver includes a positive output and a negative output. The positive output of the LED driver is connected to a positive connection point of a first LED board and the negative output of the LED driver is connected to a negative connection point of a last LED board to distribute power or current approximately evenly across the LED boards. Distributing power or current approximately evenly across the LED boards or balancing current through the LED boards can cause the brightness or intensity of various LEDs in the lighting system to be approximately the same.Type: GrantFiled: April 28, 2017Date of Patent: January 2, 2018Assignee: ABL IP Holding LLCInventors: Feng Chen, Towfiq Chowdhury
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Patent number: 9844114Abstract: Techniques are described to allow a low-cost light fixture to produce light with a relatively high color rendering index (CRI) across a range of color temperatures. A rectified AC voltage may be provided to multiple groups of light-emitting diodes (LEDs) having characteristics related to a range of color temperatures and a target CRI level. The multiple groups of LEDs may be controlled based on a received control signal, such that the combined groups of LEDs produce combined light having a produced color temperature within the range of color temperatures, and having a produced CRI level that is approximately the target CRI level. In some implementations, the received control signal is modified by a modification circuit, and the multiple groups of LEDs may be controlled based on the modified control signal.Type: GrantFiled: December 9, 2016Date of Patent: December 12, 2017Assignee: ALB IP HOLDING LLCInventors: Towfiq Chowdhury, Michael Z. Gielniewski, Feng Chen, Alejandro Lopez
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Patent number: 9769894Abstract: An LED driver circuit provides dimming control in LED lighting applications that can accommodate an AC/DC constant voltage converter. The driver circuit provides a dimming control signal that is used to directly control the DC output current of a downstream DC/DC converter driving an LED array. The dimming control signal tracks the AC or DC output from a dimming controller such that variations in the AC or DC voltage are reflected in the dimming control signal. This dimming control signal is then provided to the downstream DC/DC converter, bypassing the AC/DC constant voltage converter to directly control dimming of the LED array. Such an arrangement lets lighting design engineers deploy the familiar and well-understood constant voltage converter topology in LED lighting applications while retaining the ability to control dimming in the LED lighting applications.Type: GrantFiled: June 27, 2014Date of Patent: September 19, 2017Assignee: ABL IP Holding LLCInventors: Towfiq Chowdhury, Feng Chen
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Publication number: 20170171933Abstract: Techniques are described to allow a low-cost light fixture to produce light with a relatively high color rendering index (CRI) across a range of color temperatures. A rectified AC voltage may be provided to multiple groups of light-emitting diodes (LEDs) having characteristics related to a range of color temperatures and a target CRI level. The multiple groups of LEDs may be controlled based on a received control signal, such that the combined groups of LEDs produce combined light having a produced color temperature within the range of color temperatures, and having a produced CRI level that is approximately the target CRI level. In some implementations, the received control signal is modified by a modification circuit, and the multiple groups of LEDs may be controlled based on the modified control signal.Type: ApplicationFiled: December 9, 2016Publication date: June 15, 2017Inventors: Towfiq Chowdhury, Michael Z. Gielniewski, Feng Chen, Alejandro Lopez
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Publication number: 20170164440Abstract: A dimmable driver for an LED light fixture allows multiple types of dimmers to be used with the light fixture. The dimmable driver may be disconnected from one type of dimmer and subsequently connected to another type of dimmer without having to replace or otherwise adjust the driver for each dimmer. Multiple types of dimmers may be connected to dimmable driver at the same time and the dimmable driver may use dimming signals from one or several of these dimmers. In some embodiments, the dimmable driver is configured to accommodate a step dimmer, a 0-10 V dimmer, and a phase-cut dimmer. Other dimmers and dimming protocols may be accommodated by the dimmable driver in alternative embodiments. Such an arrangement maximizes flexibility for lighting specifiers, contractors, and distributors while minimizing potential errors, costs, delays, and obsolete inventory.Type: ApplicationFiled: December 8, 2015Publication date: June 8, 2017Inventors: Feng-Kang Hu, Hangyang Wang, Feng Chen, Towfiq Chowdhury, Charles J. Spencer
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Patent number: 9392658Abstract: System and method for dimming solid-state lighting (SSL) avoids visual anomalies such as flicker for different types of SSL fixtures. This ability to avoid visual anomalies allows the system and method to be compatible with virtually any SSL fixture from any manufacturer. A controller is provided in some implementations that automatically generates a dimming voltage for the SSL fixtures based on a dimming control signal. A skip-phase dimming module is provided in some implementations that operates in conjunction with the controller to automatically skip dimming levels that cause visual anomalies in the SSL fixtures. A wireless module is provided in some implementations to receive signals from remote sensors and other input devices, such as ambient light sensors, occupancy sensors, color sensors, and the like.Type: GrantFiled: December 9, 2014Date of Patent: July 12, 2016Assignee: Acuity Brands Lighting, Inc.Inventors: Towfiq Chowdhury, Bobby D. Taylor
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Publication number: 20160165693Abstract: System and method for dimming solid-state lighting (SSL) avoids visual anomalies such as flicker for different types of SSL fixtures. This ability to avoid visual anomalies allows the system and method to be compatible with virtually any SSL fixture from any manufacturer. A controller is provided in some implementations that automatically generates a dimming voltage for the SSL fixtures based on a dimming control signal. A skip-phase dimming module is provided in some implementations that operates in conjunction with the controller to automatically skip dimming levels that cause visual anomalies in the SSL fixtures. A wireless module is provided in some implementations to receive signals from remote sensors and other input devices, such as ambient light sensors, occupancy sensors, color sensors, and the like.Type: ApplicationFiled: December 9, 2014Publication date: June 9, 2016Inventors: TOWFIQ CHOWDHURY, BOBBY D. TAYLOR
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Publication number: 20160128155Abstract: A dimmable LED lighting system includes first, second and third types of LED light sources, and an LED driver to control the supply of current on first, second and third channels, respectively to the first, second and third types of LED light sources. The first, second and third types of LED light sources are selected according to their spectral power distribution (SPD) curves. The selected SPD curves together model a dimming color curve that is characteristic of an incandescent light source when the first, second and third types of LED light sources are separately driven with current at predefined power ratios that correspond to dimming levels over a dimming region of the dimming color curve. The dimmable LED lighting system can have a color rendering index Ra greater than 80 over the dimming region.Type: ApplicationFiled: October 31, 2014Publication date: May 5, 2016Inventors: Raghuram L.V. PETLURI, Towfiq CHOWDHURY
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Publication number: 20150382421Abstract: An LED driver circuit provides dimming control in LED lighting applications that can accommodate an AC/DC constant voltage converter. The driver circuit provides a dimming control signal that is used to directly control the DC output current of a downstream DC/DC converter driving an LED array. The dimming control signal tracks the AC or DC output from a dimming controller such that variations in the AC or DC voltage are reflected in the dimming control signal. This dimming control signal is then provided to the downstream DC/DC converter, bypassing the AC/DC constant voltage converter to directly control dimming of the LED array. Such an arrangement lets lighting design engineers deploy the familiar and well-understood constant voltage converter topology in LED lighting applications while retaining the ability to control dimming in the LED lighting applications.Type: ApplicationFiled: June 27, 2014Publication date: December 31, 2015Inventors: Towfiq CHOWDHURY, Feng CHEN