Key to optimizing the working life of the LED light bulbs

LED driver circuit to the standard AC voltage is converted to a DC current and voltage used.
To make LED bulbs are compatible with standard light mouth, without sacrificing its working life, the designer must somehow not increase bulb potential failure mechanisms in the way, the drive circuit is integrated together with the bulb.
The driving circuit to a high AC voltage to low DC voltage, and therefore must be electrically isolated. One solution is to use real-time waveform analysis, through the isolation transformer primary side detection LED high bay light current, so that no direct feedback from the output side, you can keep the LED string Yan Geheng flow regulation.

LED driver in front of a two-step solution is a boost converter, to provide the required dimmer load impedance (to reduce the inrush current may cause damage), and the input current in phase with the line current, thereby increasing the circuit The overall power factor.
Governments around the world have introduced provisions requires incandescent gradually withdraw from the market, which contributed to the solid-state lighting technology changes. LED high bay light compared to traditional methods have significant advantages, especially LED bulbs lumens per watt improved performance, while reducing the cost per lumen.
LED technology with traditional incandescent lamp is replaced, the main benefit is a longer working life, and lower cost per watt hour. Relatively weak compared to incandescent and fluorescent lamps, rugged solid-state lighting technology is an important selling point for consumers. A typical incandescent lamp life is about 1000 hours (Reference 1). The LED bulb claims to have more than 50,000 hours working life (Reference 2), while the equivalent light output, the power consumption is only about 20% of the former.
However, if the designer does not take the necessary precautions, LED lighting may not be able to deliver to the consumer about 25 years without replacement bulb commitments. LED and its drive circuit complexity and reliability (must also be compatible with conventional dimming technology) are the designer must consider the problem, so as to get the longest working life of LED lighting systems.
LED work requires a constant DC current, and the voltage is much lower than the rectified AC line voltage, the AC voltage is reduced to the standard power level to a driving circuit. To make the LED light bulb lamp socket is compatible with the standard, the designer must be integrated in the lamp drive circuit inside. If not handled properly, this integration will increase the LED bulbs possibility of mechanical failure.
LED bulbs drive past a large number of external components are required, expensive isolation components, and special design strategies to prevent prolonged aging critical components (such as electrolytic capacitors). Now, the integration of the lamp drive circuit is more prone to reliability problems, such as early failure or the MTTF (MTBF) rate.
MTTF is the first time a measure of the value of failure, usually in the circuit of each component FIT rate (per 1 billion hours failure rate) is calculated. Since the drive circuit to a large AC voltage (100Vac/220V ac) for the LED is reduced to a dc voltage supply, so do electrical isolation for safety reasons.
In a typical electrically isolated AC / DC converter, would use a separate optical isolator (or coupler) to provide primary side from the secondary end of the feedback controller, which will convert an electrical signal into an optical signal, so that the signal through the light barrier, and then converted back to an electrical signal (Figure 1). FIT optocoupler higher because the semiconductor element, and therefore reduces the overall circuit MTTF targets.

In addition, because the effects of aging, optocoupler current transfer rate may vary with time and temperature changes. Such changes would affect the stability of the power supply circuit, to shorten the life of the LED high bay light driver circuit. Although many LED lamps and luminaires can operate at a high temperature of the PCB, but the designer must eliminate these weaknesses, in order to obtain a longer life.
Figure 2 shows the primary side of iWatt digital control PrimAccurate. This patented real-time waveform analysis program, the primary side of the isolation transformer to detect the LED current, without the need for a direct feedback from the output terminal, the LED string while maintaining strict Constant current regulation.

More info you can visit: www.lead-lighting.com