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LED Module Manufacturing
Published in M. Nisa Khan, Understanding LED Illumination, 2013
Most common power supplies provide a constant voltage output such as batteries and mains and therefore an LED driver requires an additional power converter to generate a constant current source. Such a converter uses IF as the error signal in a feedback loop to alter the voltage from the power supply in order to maintain a constant IF. Since direct measurement of IF is often difficult, monitoring other parameters (e.g., a sensor resistor value within the corresponding circuit) can allow for a good estimate of IF.
Fuses and Relay Circuits
Published in Dorin O. Neacşu, Automotive Power Systems, 2020
Since the optocoupler part of the solid-state relay is connected with the electronic circuit, a brief design example is herein included. The optocoupler is composed of two devices, an emitting LED and a receiving phototransistor. The LED driver needs to ensure a fast transmission of information, to protect against negative voltages, to limit the driving current under the LED limits—usually with a series resistances, to sustain operation for the entire temperature range, and to address lifetime and reliability concerns. An example circuit is shown in Figure 11.9.
A Case Study on the Smart Streetlighting Solution Based on 6LoWPAN
Published in Mohammad Ayoub Khan, Internet of Things, 2022
Manoj Kumar, Prashant Pandey, Salil Jain
This module provides the core functionality of a streetlight system and has several components (Figure 10.2) like a high-efficiency LED driver, a battery management system, and a solar module. Readers should note that the battery management system and solar module are not essential components in this architecture. A smart streetlight system is expected to use high-efficiency LEDs that require dedicated driver circuitry for optimal operation (Arumugam et al., 2020). LED drivers are basically constant current power suppliers while more sophisticated drivers also consider LED aging and operating temperatures. Some LED driver may support PWM-based dimming (Jha & Kumar, 2019). It's important to do switching at higher frequencies to avoid flicker. Quasi-resonant topology is generally used in the LED driver design as it's efficient and cost effective. If the light is installed in a far-flung place, it's also useful to have a set of solar panel and batteries. An MPPT charger is required to charge the batteries from the solar panel during the daytime, so that lights can run on battery during the night time (Hiwale et al., 2014). Lighting module is generally located inside the enclosure of the LED lamp; however, in some implementations, it may be present inside a separate enclosure. The enclosure including the LED lamp assembly is also called a light fixture, or a luminaire. In more compact designs, LED driver, sensor module, processing module, and communication module, etc., may be mounted on the same PCB. This approach can reduce cost and space requirements; however, careful design is needed to ensure that the electronics are not affected by the heat generated by LEDs and the Radio Frequency (RF) signal is not obstructed by metallic parts.
An Improved Z-Source Derived converter for Efficient PV Integration
Published in International Journal of Electronics, 2023
Yugal Kishor, Ramnarayan Patel, Lalit Kumar Sahu
To overcome aforesaid challenges, a new cascaded boost and ZS with SC (CZSSC) based high gain topology is proposed in this brief. The proposed converter is implemented by judiciously combining the classical boost cell at input stage of ZSSC to achieve significantly high gain at reduces device stress and higher device utilization factor. The key contributions of presented article in comparison with existing topologies are: (1) High voltage gain is achieved with simple structure. (2) Reduced voltage stress on converter components. (3) Higher device utilization factor. (4) Acceptance of wide input variations. (5) The converter has continuous input current. In addition, a high voltage gain is attained without the use of HFT and coupled-inductor, resulting in the elimination of voltage overshoot in switches during the turn-off procedure. Which reduces the conduction losses by using low voltage rating switches with lower Rds(on). Additionally, the converter is functioning with a constant input current. Hence, it is suitable for the integration of renewable energy sources, such as PV, FC, and light-emitting diode (LED) driver applications. The proposed converter has been thoroughly evaluated at steady-state and includes design guidelines. The experimental validation of the implemented converter’s theoretical analysis and performance was conducted through a 400W laboratory prototype.
A Novel Emergency Lighting System Design Eliminating Extra Phase Line Installation
Published in IETE Journal of Research, 2023
Zeynep Hasirci Tugcu, Ismail Hakki Cavdar
There are three critical points for the design of the proposed system: Obtaining the required luminosity using LED lamp, Charging the battery of the LED lamp without an extra cable, and Detection of the electrical system conditions: Normal (NM), Idle (IM), and Emergency (EM). The block diagram of the proposed LED-PLC ELS which has two main parts: PLC & control side and ELS side is provided in Figure 2. The key components in the PLC & control side are the switched-mode power supply (SMPS), PLC oscillator, power amplifier (PA), and the coupler while components on the ELS side are the coupler, charger, battery, LED driver, and LED lamp. PLC & control circuitry is powered by the F line (at Node 1) before the light control switch (S) and injects into the ELS side (at Node 2) after S switch. The PA amplifies the high-frequency low voltage oscillator signal (PLC Carrier OSC signal) to 12 V, 1.25 A values and transmits the PLC signal through the coupler to Node 2 after the S switch.
A Universal Input PFC CSC Converter in Low Power Consumer Lighting Applications
Published in IETE Technical Review, 2020
Bhim Singh, Somnath Pal, Ashish Shrivastava
Since LEDs are only operational with a DC supply, the AC supply voltage needs to be rectified and filtered. Figure 1 shows diode bridge rectifier (DBR) fed a conventional LED driver. It consists of a large DC-link capacitor (Cdc) for input ripple voltage filtering and an output inductor (Lo) to reduce flicker in LED light output. In general, conventional schemes are rugged and cost-effective. Since there are no controllers associated with this scheme, a small voltage fluctuation to the AC side causes severe current variation through the LED load which leads to failure of LEDs. Moreover, this kind of scheme draws large pulsating current from AC mains supply as shown in Figure 1, which is rich in harmonics and increases total harmonic distortion (THDi).