LED bulb light engine

If you want to take the LED bulb lamp, if you want to become a light engine, it must be the power board and LED board into a board, you can see that the difficulty is great.

For the bulb, it is very close to the standard. It is mainly composed of three parts: LED light source, constant current drive power supply, radiator and shell (including lamp holder and lamp shade). So if you take the LED bulb bulb, if you want to become a light engine, it must be the power board and LED board into a board, you can see that the difficulty is great.

First, the switching power supply is not suitable for light engine switching power supply, although the performance is good, the efficiency is relatively high, but the biggest drawback is that the number of components is very large, and the LED lamp board is very difficult to integrate together.

LED bulb light engine

Two, linear power supply can reduce the number of components but low efficiency in order to reduce the number of components, the simplest method is to use linear power supply, linear power supply usually only 5-6 components, so it can greatly reduce the occupied area. At present, most of the light engine on the market is a linear constant current source without electrolytic capacitor. Its basic principle is to access the different value of the constant current drive LED on input AC voltage waveform of different values, the current waveforms obtained after half sine wave form and AC rectifier matching, which can get close to the power factor of 1. This can be understood from the internal structure and waveform of the chip.

Its current and voltage waveforms are shown in figure 4. It is shown that when the AC voltage rises to a certain value when the first switch is switched on, the first series of LED conduction, and the first constant current source; continue to rise to higher value when the first switch, the second switch is switched on, the first series with second series LED with higher current second a constant current source is conducted, and so on, finally a turn-on time is the shortest, but the conduction current maximum (the last one constant current source). Thus, a current waveform close to the voltage waveform (half sine wave) is obtained, and the highest power factor is obtained. But it also brings a series of shortcomings and problems.