LED driven design experience

　　To popularize LED lighting, not only need to significantly reduce costs, but also need to solve technical problems. How to solve the energy efficiency and reliability of these challenges, vice president of marketing Doug Bailey shared Power Integrations highly reliable and efficient LED driver design experience.

　　First, do not use bipolar power devices

　　Doug Bailey noted that due to the bipolar power devices cheaper than the MOSFET, usually about 2 cents/unit, so some designers in order to reduce the cost of LED driver using bipolar power devices, this will seriously affect the reliability of the circuit, because with LED enhance the driving circuit board temperature, the effective operating range of bipolar devices will rapidly shrink, this will cause a temperature rise in the device failure which affects the reliability of LED lamps, the correct approach is to choose a MOSFET device, life MOSFET devices much longer than bipolar devices.

　　Second, try not to use electrolytic capacitors

　　LED driver circuit in the end not to use electrolytic capacitors? There are supporters and opponents, supporters believe that if you can control the temperature of the circuit board, in order to extend the life of electrolytic capacitors to achieve the purpose, such as choice of 105 degrees high temperature life of 8,000 hours of electrolytic capacitors, electrolytic capacitor life estimation formula based on the prevailing "reduce the temperature every 10 degrees, doubling the life", then it at 95 degrees ambient operating life of 16,000 hours at 85 degrees ambient operating life of 32,000 hours at 75 degrees ambient operating life of 64,000 hours, if the actual lower operating temperature, then life will be longer! Seen in this light, as long as the selection of high-quality electrolytic capacitors for the life of the drive power is no effect!

　　There's supporters believe that the non-electrolytic capacitors of the high ripple current and low-frequency flicker will cause some physical discomfort caused by the human eye, the amplitude of the low frequency ripple will lead to some poor digital camera equipment appears frequency flashing light and dark grid. Therefore, high-quality light fixtures still need to electrolytic capacitors. But opponents argued that the electrolytic capacitor will naturally aging, in addition, LED lighting is extremely difficult to control the temperature, so inevitably reduce the life of electrolytic capacitors, thus affecting the life of LED lamps.