# Automotive Lighting

The Experts below are selected from a list of 819 Experts worldwide ranked by ideXlab platform

### Joseph S. Chang – 1st expert on this subject based on the ideXlab platform

• ##### a low emi high reliability pwm based dual phase led driver for AutomotiveLighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018
Co-Authors: Yong Qu, Joseph S. Chang

Abstract:

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 AutomotiveLighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018
Co-Authors: Yong Qu, Joseph S. Chang

Abstract:

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 – 2nd expert 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, 2017
Co-Authors: Young Hyun Song, Mong Kwon Jung, Seok Bin Kwon, Won Kyu Park, Bong Kyun Kang, Woo Seok Yang, Dae Ho Yoon

Abstract:

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 AutomotiveLighting fabrication luminous emittance and tunable color space
Dyes and Pigments, 2017
Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho Yoon

Abstract:

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 AutomotiveLighting 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 AutomotiveLighting: Fabrication, luminous emittance, and tunable color space
Dyes and Pigments, 2017
Co-Authors: Young Hyun Song, Eun Kyung Ji, Byung Woo Jeong, Mong Kwon Jung, Dae Ho Yoon

Abstract:

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 AutomotiveLighting 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.

### Yong Qu – 3rd expert on this subject based on the ideXlab platform

• ##### a low emi high reliability pwm based dual phase led driver for AutomotiveLighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018
Co-Authors: Yong Qu, Joseph S. Chang

Abstract:

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 AutomotiveLighting
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018
Co-Authors: Yong Qu, Joseph S. Chang

Abstract:

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.