"Efficient and reliable" LED lighting design three major advice
W12 four roller plate rolling machine Ydraulic Plate Roll Bending Machines,4-Roller Plate Rolling Machine,Plate Bending Machine Design Hvcen Machinery Technology Co., Ltd. , http://www.elh-press.com
"China Building Materials Network" opened the prelude to the large-scale popularization of LED lamps around the world in 2011, which has delighted thousands of Chinese LED lighting manufacturers in the Nuggets green lighting revolution - because a huge market is about to open, and This time, the protagonist is a Chinese manufacturer. LED lamps need to be popularized, not only need to reduce costs significantly, but also need to solve the problem of energy efficiency and reliability. How to solve these problems, let us share three tips on high-efficiency and high-reliability LED lamp design.
Do not use bipolar power devices. Doug Bailey points out that because bipolar power devices are cheaper than MOSFETs, typically around 2 cents, some designers use bipolar power devices to reduce LED drive costs, which can seriously affect the circuit. Reliability, because as the temperature of the LED driver board increases, the effective working range of the bipolar device will shrink rapidly, which will cause the device to malfunction when the temperature rises, thus affecting the reliability of the LED lamp. The correct approach is to use the MOSFET. Devices, MOSFET devices have a much longer lifetime than bipolar devices.
Try to use integrated MOSFETs
If the LED luminaires are not designed to be very powerful, Doug recommends using an LED driver with integrated MOSFETs because the benefit of this is that the integrated MOSFETs have less on-resistance and generate less heat than discrete, in addition to integrated MOSFETs. The controller and the FET are generally together, and generally have a thermal shutdown function. When the MOSFET overheats, the circuit is automatically turned off to protect the LED lamp. This is very important for the LED lamp, because the LED lamp is generally small and difficult to dissipate air. . Sometimes LEDs can hurt people due to overheating, but our solution has never been like this. He said.
Try to use the single-stage architecture circuit Doug to indicate that some LED circuits use a two-stage architecture, PFC (Power Factor Correction) isolated DC/DC converter architecture, which will reduce the efficiency of the circuit. For example, if the efficiency of the PFC is 95 and the efficiency of the DC/DC section is 88, the efficiency of the entire circuit will be reduced to 83.6! PI's LinkSwitch-PH device combines a PFC/CC controller, a 725V MOSFET, and a MOSFET driver into a single package, increasing the efficiency of the driver circuit to 87! Doug pointed out that such a device can greatly simplify the layout of the board, and can eliminate up to 25 components used in the traditional isolated flyback design! The components that are omitted include high voltage bulk electrolytic capacitors and optocouplers. Doug said that the LED two-stage architecture is suitable for older drivers that must use a second constant current drive circuit to enable the PFC to drive the LEDs at constant current. These designs are outdated and no longer cost effective, so in most cases it is best to use a single stage design.