Australia has pioneered the forbidden of incandescent lamps in International LED lighting market, which lifts the curtain on the popularization of LED lights. In addition, with the European Union, Japan, Canada and other countries prohibiting the use of incandescent lamps in 2012, the popularity rate of LED lights will be further improved, allowing thousands of LED lighting manufacturers in China who support green revolution rejoice – because a huge market will open, and the Chinese manufacturers will play a leading role.
First, do not use bipolar power devices.
Since bipolar power devices, generally costing about 2 cents, are cheaper than the MOSFET, some designers use bipolar power devices to reduce the cost of LED lighting driver. But it will seriously affect the reliability of the circuit because with the ascension of temperature on the circuit board of LED light driver, the effective operating range of bipolar devices will reduce rapidly, thus causing the device to malfunction and affecting the reliability of LED lights. The correct approach is to use MOSFET devices since they can work longer than bipolar devices.
Secondly, the withstand voltage of MOSFET should not lower than 700V.
Many believe that the input voltage of LED lights is generally 220V, so it is enough to have a 600V withstand voltage. But in many occasions, the circuit voltage could reach to 340V. And when there is surge, a MOSFET with 600V could breakdown easily, thus affecting the life span of LED lights. Actually, using a MOSFET with 600V might save some costs, but it is at the cost of the entire circuit board.
Thirdly, try not to use electrolytic capacitors
Whether an electrolytic capacitor should be used in LED lighting driver circuit to the end? There are proponents and opponents. The proponents believe that one can control the temperature of the circuit board, thus achieving the purpose of extending the life of electrolytic capacitors. Take 105 degrees of high-temperature electrolytic capacitors with a lifespan of 8,000 hours For instance. According to the prevailing life estimation formula of electrolytic capacitors: temperature decreases every 10 degrees, lifespan doubles; when the environment temperature is 95°,the working life is 16,000 hours; when the environment temperature is 85°, the working life is 32,000 hours; when the environment temperature is 75°,the working life is 64000 hours. If the actual operating temperature is lower, then life will be longer! By this token, as long as it selects high-quality electrolytic capacitors, there will be no influences on the lifespan of the driver power.
Fourth, making full use of MOSFET devices
If the power of the designed LED lights is not very high, we recommend using the LED lights with integrated MOSFET driver because it has less resistance on electricity and less heat generation than discrete. In addition, the integrated MOSFET combines controller with the FET together. It has the function of shut off power when it is overheating. Automatically shutting down circuit when MOSFEL is overheating can protect LED lights, which is very important to LED lights because the LED lights are generally very small and difficult to achieve air cooling. “Sometimes burning may happen due to LED overheating, but our designs could never occur such accidents.” He said.
Fifth, making use of single-stage framework circuit
Some LED light circuits use two-level-structure, namely “PFC (Power Factor Correction) + isolation DC / DC convertor” architecture, this design will reduce the efficiency of the circuit.