With the development of LED technology, the application of LED has expanded from the traditional low-power portable product backlight to medium and high power indoor lighting, outdoor lighting and flashlight applications. Depending on the driving power supply, LED lighting can usually be divided into AC-DC LED lighting, DC-DC LED lighting power supply and battery-powered LED flashlights. LED lamps and their power are also available. Different, such as 3WPAR16, 3 & TImes; 2WPAR20, 10W/15WPAR30, 15W/22WPAR38, 1WG13, 3WGU10, 1WMR11, 3WMR16, 3W/9W/15W downlight, 1W-3W reading lamp, etc.
1 AC-DCLED lighting solutionIn isolation applications where there is no physical electrical connection between the AC line voltage and the LED, common topologies are flyback and dual inductor plus single capacitor (LLC) half-bridge resonance. Different topologies are suitable for different power ranges or for special design requirements. For example, the flyback topology is the standard choice for medium to low power applications of less than 100W, while the LLC half-bridge topology is the preferred solution for high power and energy efficiency.
Figure 1: Isolated topology with different power ranges
In AC-DCLED lighting applications, low-power LED applications are typically driven with constant current (CC), while constant voltage (CV) functions are used as protection functions in the case of open outputs. High-power LED applications may require the addition of power factor correction (PFC) in the circuit, where both the AC-DC conversion and the LED-driven two-part circuit may be in an integral configuration, ie, the two are fused together and are located in the illumination. Within the luminaire, a distributed configuration can also be used, as shown in Figure 2, to simplify security considerations and increase system flexibility.
Figure 2: Distributed configuration of high-power LED drivers
From the specific power range of the application, the application of AC-DCLED lighting power solutions mainly includes:
ï¬-1W-8W: G13/GU10/PAR16/PAR20 lighting
ï¬-8W-25W: PAR30/PAR38 lighting
ï¬-50W-300W: area lighting
1) 1W-8WAC-DCLED lighting application
This type of application requires an input voltage of 90 to 264Vac and an energy efficiency of 80%. It also provides protection features such as short-circuit protection and overvoltage protection, and provides 350mA and 700mA constant current. Applications include G13, GU10, PAR16, PAR20 and recessed lights. (downlight) and so on.
ON Semiconductor's NCP1015 self-powered monolithic switching regulator can be used in this type of application. This device integrates a fixed frequency (65/100/130kHz) current mode controller and a 700V high voltage MOSFET to provide all the features needed to build a robust, low cost power supply such as soft start, frequency jitter, short circuit protection, skip cycle, Maximum peak current set point and dynamic self-powered function (no auxiliary winding required). Figure 3 shows a circuit diagram of the NCP1015 in an isolated 1W-8W range AC-DCLED lighting application. It is worth mentioning that the NCP1015 can also be used in non-isolated (high-frequency transformers in the circuit) 1W-8W range AC-DCLED lighting applications. Tapped inductors can be used in the circuit to increase the duty cycle of the MOSFET. And improve system energy efficiency and circuit performance.
Figure 3: Electrode diagram of the LED driver application circuit (input voltage 85 to 264 Vac)
Original Electronics Technology (Suzhou) Co., Ltd. , https://www.original-te.com