Will high voltage LEDs dominate future LED general lighting?

Recently, many websites have reported a kind of "high-voltage LED", which is considered to be a brand-new LED variety, and has many advantages. It is even thought that it will make "today's low-voltage LEDs will fade out of the future LED general lighting market" and high-voltage LEDs. Will it be "to dominate the future of LED general lighting", is this really the case?

We know that the Chinese of LED is "light-emitting diode", which is basically a kind of "diode". And it is a diode that works in the positive direction. In the past, there were only high back pressure diodes, which meant high reverse breakdown voltages. If the work is in the positive direction, then the higher the voltage, the greater the current. However, the biggest feature of this high-voltage LED is high voltage and small current. What is it about?

1. What is a high voltage LED?

Take a closer look, it turns out that it is just a lot of 20mA low-power LEDs connected in series, becoming a so-called high-voltage LED. It is not new to connect many low-power LEDs in series. In fact, it has been used in many lamps. The only difference is that in the past, the luminaire manufacturers connected the small power LEDs that had been packaged together. For example, Figure 1 shows that Shanghai Longxing Company has connected 80 surface-mounted 0.1W low-power LEDs in series to obtain high-voltage and low-current characteristics for LED bulbs.

Figure 1. Series connection of 80 0.1W low power LEDs

Now it is a small power LED that is connected in series by the LED manufacturer and it is called "high voltage LED". It is just one of the integrated LEDs. In fact, there have been various integrated LEDs in the past, with different numbers of LED strings connected in parallel to obtain LEDs of various power and voltage. It can be said that the first American Bridgeex company has already launched this integrated LED. That is to say, a lot of low-power LEDs are connected in series on the substrate to obtain a high-power LED. They call it LED arrays. For example, a 30W LED array BXRA-C2000, which they introduced in 2009, actually has 25 1W LEDs on the chip 5 and 5 strings, and its size is 25.3x22.3mm. The diameter of the light-emitting surface is 17.5 mm (Fig. 2), the forward voltage is 16.6 V, the forward current is 1.75 A, and the thermal resistance is 0.5 °C/W.

Figure 2. Integrated LEDs from Puri USA

The main difference between high voltage LEDs and this integrated LED is that the high voltage LEDs are all in series, while the integrated LEDs are in series and parallel. The integrated LED is characterized by a slotting method on a large wafer, which is cut into many small LEDs. The depth of the trench is about 4-8 μm, and the trench should not be too wide to avoid reducing the light-emitting area. After the trench is opened, in order to lay the wires connecting the LEDs, the trenches are filled with an insulating layer, and the corresponding aluminum wires are applied in accordance with the requirements of series or parallel connection.

2. Performance indicators of high voltage LED

At present, only Taiwan's Jingyuan Optoelectronics is producing such high-voltage LEDs, but at the website of Jingyuan Optoelectronics: http://?MID=3&AID=2

Only a few HV LEDs with low voltages were found. Its indicators are shown in the following table:

Epistar HVLED indicator

There is no high-voltage LED with a voltage of 50V that they promote. It seems that the real high-voltage LED is not yet mature. Therefore, there is no quantitative comparison.