The Experts below are selected from a list of 405 Experts worldwide ranked by ideXlab platform
Xiaodong Liu - One of the best experts on this subject based on the ideXlab platform.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong LiuAbstract:Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED Current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED Current ripple. This paper proposes an average Current modulation method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average Current modulation circuit requires a single low-voltage MOSFET, a Current Sense Resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the Current modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.
Brian J White - One of the best experts on this subject based on the ideXlab platform.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
European Conference on Cognitive Ergonomics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei LiuAbstract:Conventional single-stage AC-DC LED drivers with a high power factor contain significant LED Current ripple at twice the AC line frequency, and require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a DC voltage to ensure a limited low frequency Current ripple. This paper proposes an average Current modulation method that is capable of driving LEDs from a voltage that contains significant AC ripple, while maintaining zero low frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic type capacitors, and prolonging the life of the LED driver. The average Current modulation circuit requires a single low voltage MOSFET, a Current Sense Resistor and a simple control circuit. By requiring no additional magnetic components, the cost of the average Current modulation circuit is very low, and has minimal impact on the efficiency of the overall LED driver. A 25 W experimental prototype with a Flyback PFC converter has been built to verify the capability and excellent performance of the proposed driving technique.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong LiuAbstract:Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED Current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED Current ripple. This paper proposes an average Current modulation method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average Current modulation circuit requires a single low-voltage MOSFET, a Current Sense Resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the Current modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.
Yanfei Liu - One of the best experts on this subject based on the ideXlab platform.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
European Conference on Cognitive Ergonomics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei LiuAbstract:Conventional single-stage AC-DC LED drivers with a high power factor contain significant LED Current ripple at twice the AC line frequency, and require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a DC voltage to ensure a limited low frequency Current ripple. This paper proposes an average Current modulation method that is capable of driving LEDs from a voltage that contains significant AC ripple, while maintaining zero low frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic type capacitors, and prolonging the life of the LED driver. The average Current modulation circuit requires a single low voltage MOSFET, a Current Sense Resistor and a simple control circuit. By requiring no additional magnetic components, the cost of the average Current modulation circuit is very low, and has minimal impact on the efficiency of the overall LED driver. A 25 W experimental prototype with a Flyback PFC converter has been built to verify the capability and excellent performance of the proposed driving technique.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong LiuAbstract:Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED Current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED Current ripple. This paper proposes an average Current modulation method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average Current modulation circuit requires a single low-voltage MOSFET, a Current Sense Resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the Current modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.
Hongliang Wang - One of the best experts on this subject based on the ideXlab platform.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
European Conference on Cognitive Ergonomics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei LiuAbstract:Conventional single-stage AC-DC LED drivers with a high power factor contain significant LED Current ripple at twice the AC line frequency, and require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a DC voltage to ensure a limited low frequency Current ripple. This paper proposes an average Current modulation method that is capable of driving LEDs from a voltage that contains significant AC ripple, while maintaining zero low frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic type capacitors, and prolonging the life of the LED driver. The average Current modulation circuit requires a single low voltage MOSFET, a Current Sense Resistor and a simple control circuit. By requiring no additional magnetic components, the cost of the average Current modulation circuit is very low, and has minimal impact on the efficiency of the overall LED driver. A 25 W experimental prototype with a Flyback PFC converter has been built to verify the capability and excellent performance of the proposed driving technique.
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an average Current modulation method for single stage led drivers with high power factor and zero low frequency Current ripple
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong LiuAbstract:Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED Current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED Current ripple. This paper proposes an average Current modulation method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency Current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average Current modulation circuit requires a single low-voltage MOSFET, a Current Sense Resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the Current modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.
Jose C Principe - One of the best experts on this subject based on the ideXlab platform.
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A wireless power interface for rechargeable battery operated medical implants
2007Co-Authors: Student Member, Jose C Principe, Rizwan BashirullahAbstract:Abstract—This paper describes an integrated analog front-end for wireless powering and recharging of miniature Li-ion batteries used in implantable neural recording microsystems. DC signal extraction from a wireless carrier is accomplished using Schottky barrier contact diodes with lower forward voltage drop for improved efficiency. The battery charger employs a new control loop that relaxes comparator resolution requirements, provides simultaneous operation of constant-Current and constant-voltage loops, and eliminates the external Current Sense Resistor from the charging path. The accuracy of the endof-charge detection is primarily determined by the voltage drop across matched Resistors and Current-sources and the offset voltage of the Sense comparator. Experimental results in 0.6μm bulk CMOS technology indicate that ±1.3 % (or ±20μA) end-ofcharge accuracy can be obtained under worst-case conditions for a comparator offset voltage of ±5mV. The circuits occupy 1.735mm 2 with a power dissipation of 8.4mW when delivering a load Current of 1.5mA at 4.1V (or 6.15mW) for an efficiency of 73%. I
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A low power battery management system for rechargeable wireless implantable electronics
2006 IEEE International Symposium on Circuits and Systems, 2006Co-Authors: Pengfei Li, Rizwan Bashirullah, Jose C PrincipeAbstract:An integrated battery management system for low power wireless implantable electronics is presented herein. The system is designed for miniature implantable Li-ion rechargeable batteries with limited cell capacity and employs a new control loop that relaxes comparator resolution requirements, provides simultaneous operation of constant-Current and constant voltage loops, and eliminates the external Current Sense Resistor from the charging path. The accuracy of the end-of-charge detection is primarily determined by the voltage drop across matched Resistors and Current-sources and the offset voltage of the Sense comparator. Preliminary simulations in 0.5mum bulk CMOS technology indicate that plusmn1% (or plusmn15muA) end-of-charge accuracy can be obtained under worst-case conditions for a comparator offset voltage of plusmn5mV. The proposed battery control loop measures roughly 170mum by 960mum and dissipates approximately 150muWatts
