LED drive power circuit design issues

In the design process of LED power products, engineers need to deal with not only the circuit design issues, but also more LED driver options, LED lifetime maintenance, and later maintenance and troubleshooting. Today Xiao Bian has specially put together some practical experience in the process of LED inspection and LED power supply design. Through the form of question and answer, they are shared with the new engineers. Let's take a look.

The first question: When designing LED power products, how can we design high quality LED driver circuits?

It is believed that many engineers engaged in LED power supply design are very clear that LED is a long-lived electronic component that is currently being developed in the world. In an ideal situation, the LED's working life can reach 50,000 hours, but the application circuit design is unreasonable. The poor design of power dissipation and other factors will affect its service life. In the face of this problem, using a new generation of LED driver ICs that can eliminate electrolytic capacitors is a practical solution.

For engineers engaged in the research and development of LED power supplies and peripheral products, when designing a new generation of driver ICs, it is necessary to break the conventional DC-DC topology design thinking, and it is possible to use constant power and abandon the hysteresis-controlled step-down type. Design ideas for new product development, using constant-frequency constant current control is also a good idea. In addition, the high-quality LED driver circuit circuit should strive for simplicity, reduce the number of components used, and effectively improve the PWM controller's duty cycle. Satisfying the above conditions, the design of a new generation of driver IC can meet the design requirements of high-quality drive circuits.

The second question: What is the principle of breakdown of an LED by electrostatic discharge and what is the principle of breakdown?

During the debugging of the LED power supply, it is believed that engineers have encountered the situation where the LED components were broken after the prototype was turned on, and a considerable part of this was broken down by static electricity. LED as a semiconductor, its PN junction is directly exposed to the outside, it is easy to contact static electricity. When the charge of different polarity on the two electrodes of the LED accumulates to a certain extent and cannot be released in time, when the charge energy exceeds the maximum value of the LED chip at this time, the charge will be extremely short in the two electrode layers of the LED. Between the discharge, and the local will form a high temperature above 1400 °C between the conductive layer, the high temperature will melt between the conductive layer into a number of small holes, which is what we often encounter in the LED power supply test process, LED hits Wearing phenomenon.

In the new product prototype test of LED power supply, once the phenomenon of LED components being electrostatically broken down is encountered, there are unreasonable factors in the designed circuit. At this time, engineers need to make circuit design adjustments and test again.