The Experts below are selected from a list of 819 Experts worldwide ranked by ideXlab platform
Joseph S. Chang - One of the best experts on this subject based on the ideXlab platform.
-
a low emi high reliability pwm based dual phase led driver for Automotive Lighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018Co-Authors: Yong Qu, Joseph S. ChangAbstract:Light-emitting diode (LED) drivers for Automotive Lighting applications adopt pulsewidth modulation (PWM) vis-a-vis pulse frequency modulation because its ensuing electromagnetic interference (EMI) spectrum is predictable and easily mitigated. Nevertheless, present-day PWM control schemes adopted in LED drivers suffer from imprecise output current and subharmonic oscillation, which compromises reliability. In this paper, we present a PWM-based LED driver that features low EMI and high reliability. These attributes are achieved by our proposed average current control (ACC), proposed accuracy-enhanced on-chip current sensors, and our adoption of a dual-phase power stage. The ACC eliminates subharmonic oscillation by means of considering the complete inductor current profile vis-a-vis peak current adopted elsewhere. Also by means of the dual-phase power stage, good current balance and small current ripple are obtained. Collectively, the aforesaid substantially improves the reliability. To improve electromagnetic compatibility (EMC), the proposed accuracy-enhanced on-chip current sensors are monolithically realized with the ACC and power transistors—to the best of our knowledge, the first for a PWM-based dual-phase LED driver. The prototype LED driver, realized in a 130-nm BCDLite process, has an input voltage range of 5–16 V, output to drive 1–3 series-connected LEDs, provides a current regulation accuracy of at least 96.2%, dimming frequency up to 20 kHz, features a peak power efficiency of 94.7%, settling time of $5~\mu \text{s}$ , LED current range of 0.4–2.4 A, and current ripple factor of 8%. When benchmarked against the state-of-the-art LED drivers, our design features the highest peak power efficiency, the shortest settling time, highest current driving capability, and the lowest current ripple factor.
-
A Low-EMI, High-Reliability PWM-Based Dual-Phase LED Driver for Automotive Lighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018Co-Authors: Yong Qu, Joseph S. ChangAbstract:Light-emitting diode (LED) drivers for Automotive Lighting applications adopt pulsewidth modulation (PWM) vis-à-vis pulse frequency modulation because its ensuing electromagnetic interference (EMI) spectrum is predictable and easily mitigated. Nevertheless, present-day PWM control schemes adopted in LED drivers suffer from imprecise output current and subharmonic oscillation, which compromises reliability. In this paper, we present a PWM-based LED driver that features low EMI and high reliability. These attributes are achieved by our proposed average current control (ACC), proposed accuracyenhanced on-chip current sensors, and our adoption of a dualphase power stage. The ACC eliminates subharmonic oscillation by means of considering the complete inductor current profile vis-à-vis peak current adopted elsewhere. Also by means of the dual-phase power stage, good current balance and small current ripple are obtained. Collectively, the aforesaid substantially improves the reliability. To improve electromagnetic compatibility (EMC), the proposed accuracy-enhanced on-chip current sensors are monolithically realized with the ACC and power transistors-to the best of our knowledge, the first for a PWM-based dual-phase LED driver. The prototype LED driver, realized in a 130-nm BCDLite process, has an input voltage range of 5-16 V, output to drive 1-3 series-connected LEDs, provides a current regulation accuracy of at least 96.2%, dimming frequency up to 20 kHz, features a peak power efficiency of 94.7%, settling time of 5 μs, LED current range of 0.4-2.4 A, and current ripple factor of 8%. When benchmarked against the state-of-the-art LED drivers, our design features the highest peak power efficiency, the shortest settling time, highest current driving capability, and the lowest current ripple factor.
Dae Ho Yoon - One of the best experts on this subject based on the ideXlab platform.
-
Fabrication design for a high-quality laser diode-based ceramic converter for a laser headlamp application
Ceramics International, 2017Co-Authors: Young Hyun Song, Mong Kwon Jung, Seok Bin Kwon, Won Kyu Park, Bong Kyun Kang, Woo Seok Yang, Dae Ho YoonAbstract:Abstract We report on the fabrication of a YAG: Ce3+/Al2O3 ceramic converter (YAGC) under various conditions for use in laser diode (LD)-based Automotive Lighting applications. The prepared YAGC shows improved luminous characteristics regarding the use of a pore forming agent and a change in the fabrication method. In particular, when the fabrication method of the YAGC changes, an area with a yellow ring is reduced to 37.4% compared to previous fabrication methods. The results of the study indicate that the change in the YAGC fabrication method can result in an alternative for high-quality YAGC fabrication for Automotive Lighting applications.
-
design of laser driven high efficiency al2o3 yag ce3 ceramic converter for Automotive Lighting fabrication luminous emittance and tunable color space
Dyes and Pigments, 2017Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:Abstract An Al2O3/Y3Al5O12:Ce3+ ceramic phosphor plate (CPP) for which a nano-phosphor is used for a high-power laser diode (LD) application for white Automotive-Lighting is reported here. The prepared CPP shows improved luminous properties that are owing to the light propagation of the hexagonal α-Al2O3 in the CPP. The amount of α-Al2O3 added to the Y3Al5O12:Ce3+ CPP was optimized, and its impact on the luminous characteristics was investigated. The luminous properties of the Al2O3/Y3Al5O12:Ce3+ CPP are improved when compared with the Y3Al5O12:Ce3+ CPP, and the luminous emittance, as well as the conversion efficiency, is therefore also improved. The results of the present study indicate that the Al2O3/Y3Al5O12:Ce3+ CPP can serve as a potential material for the solid-state laser Lighting in Automotive applications.
-
Design of laser-driven high-efficiency Al2O3/YAG:Ce3+ ceramic converter for Automotive Lighting: Fabrication, luminous emittance, and tunable color space
Dyes and Pigments, 2017Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:Abstract An Al2O3/Y3Al5O12:Ce3+ ceramic phosphor plate (CPP) for which a nano-phosphor is used for a high-power laser diode (LD) application for white Automotive-Lighting is reported here. The prepared CPP shows improved luminous properties that are owing to the light propagation of the hexagonal α-Al2O3 in the CPP. The amount of α-Al2O3 added to the Y3Al5O12:Ce3+ CPP was optimized, and its impact on the luminous characteristics was investigated. The luminous properties of the Al2O3/Y3Al5O12:Ce3+ CPP are improved when compared with the Y3Al5O12:Ce3+ CPP, and the luminous emittance, as well as the conversion efficiency, is therefore also improved. The results of the present study indicate that the Al2O3/Y3Al5O12:Ce3+ CPP can serve as a potential material for the solid-state laser Lighting in Automotive applications.
-
High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of Automotive Lighting
Scientific Reports, 2016Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:We report on Y_3Al_5O_12: Ce^3+ ceramic phosphor plate (CPP) using nano phosphor for high power laser diode (LD) application for white light in Automotive Lighting. The prepared CPP shows improved luminous properties as a function of Ce^3+ concentration. The luminous properties of the Y_3Al_5O_12: Ce^3+ CPP nano phosphor are improved when compared to the Y_3Al_5O_12: Ce^3+ CPP with bulk phosphor, and hence, the luminous emittance, luminous flux, and conversion efficiency are improved. The Y_3Al_5O_12: Ce^3+ CPP with an optimal Ce^3+ content of 0.5 mol % shows 2733 lm/mm^2 value under high power blue radiant flux density of 19.1 W/mm^2. The results indicate that Y_3Al_5O_12: Ce^3+ CPP using nano phosphor can serve as a potential material for solid-state laser Lighting in Automotive applications.
Yong Qu - One of the best experts on this subject based on the ideXlab platform.
-
a low emi high reliability pwm based dual phase led driver for Automotive Lighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018Co-Authors: Yong Qu, Joseph S. ChangAbstract:Light-emitting diode (LED) drivers for Automotive Lighting applications adopt pulsewidth modulation (PWM) vis-a-vis pulse frequency modulation because its ensuing electromagnetic interference (EMI) spectrum is predictable and easily mitigated. Nevertheless, present-day PWM control schemes adopted in LED drivers suffer from imprecise output current and subharmonic oscillation, which compromises reliability. In this paper, we present a PWM-based LED driver that features low EMI and high reliability. These attributes are achieved by our proposed average current control (ACC), proposed accuracy-enhanced on-chip current sensors, and our adoption of a dual-phase power stage. The ACC eliminates subharmonic oscillation by means of considering the complete inductor current profile vis-a-vis peak current adopted elsewhere. Also by means of the dual-phase power stage, good current balance and small current ripple are obtained. Collectively, the aforesaid substantially improves the reliability. To improve electromagnetic compatibility (EMC), the proposed accuracy-enhanced on-chip current sensors are monolithically realized with the ACC and power transistors—to the best of our knowledge, the first for a PWM-based dual-phase LED driver. The prototype LED driver, realized in a 130-nm BCDLite process, has an input voltage range of 5–16 V, output to drive 1–3 series-connected LEDs, provides a current regulation accuracy of at least 96.2%, dimming frequency up to 20 kHz, features a peak power efficiency of 94.7%, settling time of $5~\mu \text{s}$ , LED current range of 0.4–2.4 A, and current ripple factor of 8%. When benchmarked against the state-of-the-art LED drivers, our design features the highest peak power efficiency, the shortest settling time, highest current driving capability, and the lowest current ripple factor.
-
A Low-EMI, High-Reliability PWM-Based Dual-Phase LED Driver for Automotive Lighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018Co-Authors: Yong Qu, Joseph S. ChangAbstract:Light-emitting diode (LED) drivers for Automotive Lighting applications adopt pulsewidth modulation (PWM) vis-à-vis pulse frequency modulation because its ensuing electromagnetic interference (EMI) spectrum is predictable and easily mitigated. Nevertheless, present-day PWM control schemes adopted in LED drivers suffer from imprecise output current and subharmonic oscillation, which compromises reliability. In this paper, we present a PWM-based LED driver that features low EMI and high reliability. These attributes are achieved by our proposed average current control (ACC), proposed accuracyenhanced on-chip current sensors, and our adoption of a dualphase power stage. The ACC eliminates subharmonic oscillation by means of considering the complete inductor current profile vis-à-vis peak current adopted elsewhere. Also by means of the dual-phase power stage, good current balance and small current ripple are obtained. Collectively, the aforesaid substantially improves the reliability. To improve electromagnetic compatibility (EMC), the proposed accuracy-enhanced on-chip current sensors are monolithically realized with the ACC and power transistors-to the best of our knowledge, the first for a PWM-based dual-phase LED driver. The prototype LED driver, realized in a 130-nm BCDLite process, has an input voltage range of 5-16 V, output to drive 1-3 series-connected LEDs, provides a current regulation accuracy of at least 96.2%, dimming frequency up to 20 kHz, features a peak power efficiency of 94.7%, settling time of 5 μs, LED current range of 0.4-2.4 A, and current ripple factor of 8%. When benchmarked against the state-of-the-art LED drivers, our design features the highest peak power efficiency, the shortest settling time, highest current driving capability, and the lowest current ripple factor.
Young Hyun Song - One of the best experts on this subject based on the ideXlab platform.
-
Fabrication design for a high-quality laser diode-based ceramic converter for a laser headlamp application
Ceramics International, 2017Co-Authors: Young Hyun Song, Mong Kwon Jung, Seok Bin Kwon, Won Kyu Park, Bong Kyun Kang, Woo Seok Yang, Dae Ho YoonAbstract:Abstract We report on the fabrication of a YAG: Ce3+/Al2O3 ceramic converter (YAGC) under various conditions for use in laser diode (LD)-based Automotive Lighting applications. The prepared YAGC shows improved luminous characteristics regarding the use of a pore forming agent and a change in the fabrication method. In particular, when the fabrication method of the YAGC changes, an area with a yellow ring is reduced to 37.4% compared to previous fabrication methods. The results of the study indicate that the change in the YAGC fabrication method can result in an alternative for high-quality YAGC fabrication for Automotive Lighting applications.
-
design of laser driven high efficiency al2o3 yag ce3 ceramic converter for Automotive Lighting fabrication luminous emittance and tunable color space
Dyes and Pigments, 2017Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:Abstract An Al2O3/Y3Al5O12:Ce3+ ceramic phosphor plate (CPP) for which a nano-phosphor is used for a high-power laser diode (LD) application for white Automotive-Lighting is reported here. The prepared CPP shows improved luminous properties that are owing to the light propagation of the hexagonal α-Al2O3 in the CPP. The amount of α-Al2O3 added to the Y3Al5O12:Ce3+ CPP was optimized, and its impact on the luminous characteristics was investigated. The luminous properties of the Al2O3/Y3Al5O12:Ce3+ CPP are improved when compared with the Y3Al5O12:Ce3+ CPP, and the luminous emittance, as well as the conversion efficiency, is therefore also improved. The results of the present study indicate that the Al2O3/Y3Al5O12:Ce3+ CPP can serve as a potential material for the solid-state laser Lighting in Automotive applications.
-
Design of laser-driven high-efficiency Al2O3/YAG:Ce3+ ceramic converter for Automotive Lighting: Fabrication, luminous emittance, and tunable color space
Dyes and Pigments, 2017Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:Abstract An Al2O3/Y3Al5O12:Ce3+ ceramic phosphor plate (CPP) for which a nano-phosphor is used for a high-power laser diode (LD) application for white Automotive-Lighting is reported here. The prepared CPP shows improved luminous properties that are owing to the light propagation of the hexagonal α-Al2O3 in the CPP. The amount of α-Al2O3 added to the Y3Al5O12:Ce3+ CPP was optimized, and its impact on the luminous characteristics was investigated. The luminous properties of the Al2O3/Y3Al5O12:Ce3+ CPP are improved when compared with the Y3Al5O12:Ce3+ CPP, and the luminous emittance, as well as the conversion efficiency, is therefore also improved. The results of the present study indicate that the Al2O3/Y3Al5O12:Ce3+ CPP can serve as a potential material for the solid-state laser Lighting in Automotive applications.
-
High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of Automotive Lighting
Scientific Reports, 2016Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho YoonAbstract:We report on Y_3Al_5O_12: Ce^3+ ceramic phosphor plate (CPP) using nano phosphor for high power laser diode (LD) application for white light in Automotive Lighting. The prepared CPP shows improved luminous properties as a function of Ce^3+ concentration. The luminous properties of the Y_3Al_5O_12: Ce^3+ CPP nano phosphor are improved when compared to the Y_3Al_5O_12: Ce^3+ CPP with bulk phosphor, and hence, the luminous emittance, luminous flux, and conversion efficiency are improved. The Y_3Al_5O_12: Ce^3+ CPP with an optimal Ce^3+ content of 0.5 mol % shows 2733 lm/mm^2 value under high power blue radiant flux density of 19.1 W/mm^2. The results indicate that Y_3Al_5O_12: Ce^3+ CPP using nano phosphor can serve as a potential material for solid-state laser Lighting in Automotive applications.
Richard D Roberts - One of the best experts on this subject based on the ideXlab platform.
-
Smart Automotive Lighting for vehicle safety
IEEE Communications Magazine, 2013Co-Authors: Shun Hsiang Yu, Oliver Shih, Hsin Mu Tsai, Richard D RobertsAbstract:It is believed that vehicle-to-vehicle (V2V) communications and accurate positioning with sub-meter error could bring vehicle safety to a different level. However, to this date it is still unclear whether the envisioned V2V standard, dedicated short-range communications, can become available in commercially available vehicle products, while widely available consumergrade GPS receivers do not provide the required accuracy for many safety applications. In this article, combining visible light communications and visible light positioning, we propose the use of smart Automotive Lighting in vehicle safety systems. These lights would be able to provide the functions of illumination and signaling, reliable communications, and accurate positioning in a single solution. The proposed solution has low complexity, and is shown to be scalable in high vehicle density and fast topology changing scenarios. In this article, we also present several design guidelines for such a system, based on the results of our analytic and empirical studies. Finally, evaluation of our prototype provides evidence that the system can indeed detect potential risks in advance and provide early warnings to the driver in real-world scenarios, lowering the probability of traffic accidents.
