The Experts below are selected from a list of 729 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.
Gabriel A. Rincon-mora - One of the best experts on this subject based on the ideXlab platform.
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An Accurate, Continuous, and Lossless Self-Learning CMOS Current-Sensing Scheme for Inductor-Based DC-DC Converters
2011Co-Authors: Pooya H. Forghani-zadeh, Gabriel A. Rincon-mora, Senior MemberAbstract:Abstract—Sensing current is a fundamental function in power supply circuits, especially as it generally applies to protection and feedback control. Emerging state-of-the-art switching supplies, in fact, are now exploring ways to use this Sensed-current information to improve transient response, power efficiency, and compensation performance by appropriately self-adjusting, on the fly, frequency, inductor ripple current, switching configuration (e.g., synchronous to/from asynchronous), and other operating parameters. The discontinuous, non-integrated, and inaccurate nature of existing lossless current-sensing schemes, however, impedes their widespread adoption, and lossy solutions are not acceptable. Lossless, filter-based techniques are continuous, but inaccurate when integrated on-chip because of the inherent mismatches between the filter and the power inductor. The proposed GM-C filter-based, fully integrated current-sensing CMOS scheme circumvents this accuracy limitation by introducing a self-learning sequence to start-up and power-on-reset. During these seldom-occurring events, the gain and bandwidth of the internal filter are matched to the response of the power inductor and its equivalent series resistance (ESR), effectively measuring their values. A 0.5 m CMOS realization of the proposed scheme was fabricated and applied to a current-mode buck switching supply, achieving overall DC and AC current-gain errors of 8 % and 9%, respectively, at 0.8 A DC load and 0.2 A ripple currents for 3.5 H–14 H inductors with ESRs ranging from 48 m to 384 m (other lossless, state-of-the-art solutions achieve 20%–40 % error, and only when the nominal specifications of the power MOSFET and/or inductor are known). Since the self-learning sequence is non-recurring, the power losses associated with the foregoing solution are minimal, translating to a 2.6 % power efficiency savings when compared to the more traditional but accurate series-Sense Resistor (e.g., 50 m) technique. Index Terms—Current-mode, current sensing, DC-DC converters, GM-C filter, inductance measurement, lossless, power management, self-learning, switching regulators. I
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An Accurate, Continuous, and Lossless Self-Learning CMOS Current-Sensing Scheme for Inductor-Based DC-DC Converters
IEEE Journal of Solid-state Circuits, 2007Co-Authors: H. Pooya Forghani-zadeh, Gabriel A. Rincon-moraAbstract:Sensing current is a fundamental function in power supply circuits, especially as it generally applies to protection and feedback control. Emerging state-of-the-art switching supplies, in fact, are now exploring ways to use this Sensed-current information to improve transient response, power efficiency, and compensation performance by appropriately self-adjusting, on the fly, frequency, inductor ripple current, switching configuration (e.g., synchronous to/from asynchronous), and other operating parameters. The discontinuous, non-integrated, and inaccurate nature of existing lossless current-sensing schemes, however, impedes their widespread adoption, and lossy solutions are not acceptable. Lossless, filter-based techniques are continuous, but inaccurate when integrated on-chip because of the inherent mismatches between the filter and the power inductor. The proposed GM-C filter-based, fully integrated current-sensing CMOS scheme circumvents this accuracy limitation by introducing a self-learning sequence to start-up and power-on-reset. During these seldom-occurring events, the gain and bandwidth of the internal filter are matched to the response of the power inductor and its equivalent series resistance (ESR), effectively measuring their values. A 0.5 mum CMOS realization of the proposed scheme was fabricated and applied to a current-mode buck switching supply, achieving overall DC and AC current-gain errors of 8% and 9%, respectively, at 0.8 A DC load and 0.2 A ripple currents for 3.5 muH-14 muH inductors with ESRs ranging from 48 mOmega to 384 mOmega (other lossless, state-of-the-art solutions achieve 20%-40% error, and only when the nominal specifications of the power MOSFET and/or inductor are known). Since the self-learning sequence is non-recurring, the power losses associated with the foregoing solution are minimal, translating to a 2.6% power efficiency savings when compared to the more traditional but accurate series-Sense Resistor (e.g., 50 mOmega) 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.
S Kiaei - One of the best experts on this subject based on the ideXlab platform.
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low power low voltage integrated cmos Sense Resistor free analog power current sensor compatible with high voltage switching dc dc converter
IEEE Transactions on Circuits and Systems I-regular Papers, 2019Co-Authors: Shrikant Singh, Debashis Mandal, Bertan Bakkaloglu, S KiaeiAbstract:A sensor circuit to measure the output power of a dc–dc boost for photo-voltaic (PV) maximum power point tracking (MPPT) application is presented. The proposed approach obviates the need for a series current Sense Resistor and a complex current/voltage digitization and multiplication circuitry required for calculating power. Thereby, this technique does not require analog multipliers, analog-to-digital converters, digital signal processor, and FPGA, thus reducing the bill of material, silicon area, and power consumption of the overall system. Additionally, it provides the dc electrical isolation between the high output voltage of the boost converter and the low-voltage integrated CMOS power sensor circuit. The proposed power sensor circuit is implemented using a switched capacitor differentiator and a voltage-to-time converter. This approach results in lower complexity, lower silicon area, lower power consumption, and lower component count for the overall PV MPPT system. Designed in a 180-nm CMOS process, the circuit can operate with a supply voltage of 1.8 V. It achieves a power Sense accuracy of 7.6%, occupies a die area of 0.0519 mm2, and consumes a power of 0.748 mW.
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Sense Resistor free analog power sensor for boost converter with 14 1 gain error and 9 4 offset error
Latin American Symposium on Circuits and Systems, 2018Co-Authors: Shrikant Singh, Debashis Mandal, Bertan Bakkaloglu, S KiaeiAbstract:This paper presents an analog power sensor to measure DC-DC converter output power for DC-DC voltage regulation and photo-voltaic (PV) maximum power point tracking (MPPT) applications. The proposed power sensor Senses current without using a conventional series Resistor, and provides power information without using additional circuits for power calculation. The proposed circuit is implemented using a switched capacitor differentiator and a voltage-to-time converter. Compared to the Resistor based sensing method that requires a current-to-voltage circuit, a gain block, two analog-to-digital converters (ADCs) and a digital signal processor (DSP), the proposed power sensor provides lower complexity, lower area and lower power consumption for MPPT PV applications. A prototype module is designed and the measured results show 14.1% gain error and 9.4% offset error in the power measurements.
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.
