Views: 1 Author: Site Editor Publish Time: 2022-05-25 Origin: Site
Nowadays, many LED products use constant current drive mode to drive LED, and LED connection mode is also designed according to actual circuit needs. There are generally four forms of series, parallel, mixed and array.
1. Concatenation method
The circuit of this series connection method is relatively simple. The end-to-end connection is connected together, and the current flowing through the LED is very good. Since the LED is a current-type device, the luminous intensity of each LED can basically be guaranteed to be consistent. The circuit adopting this LED connection method is simple and convenient to connect. But there is also a fatal disadvantage, that is, when one of the LEDs has an open-circuit fault, the entire LED light string will be extinguished, which will affect the reliability of use. This requires ensuring that the quality of each LED is excellent, so the reliability is correspondingly increased.
It is worth noting that if the LED constant voltage drive power is used to drive the LED, when a certain LED is short-circuited, the circuit current will increase, and when a certain value is reached, the LED will be damaged, resulting in all subsequent LEDs being damaged. However, if the LED constant current drive power supply is used to drive the LED, when a certain LED is short-circuited, the current basically remains unchanged, which has no effect on the subsequent LEDs. No matter which way it is driven, once an LED is opened, the entire circuit will not be lit.
2. Parallel connection
The parallel mode is characterized in that the LEDs are connected in parallel at the head and tail, and the voltages on each LED are equal during operation. However, the currents are not necessarily equal, even for LEDs of the same model and batch of specifications, due to the manufacturing process and other reasons. Therefore, the inability of the current distribution of each LED can make the life of the LED with excessive current decrease compared with other LEDs, and it is easy to burn out over time. This parallel connection circuit is relatively simple, but the reliability is not high, especially in the case of a large number of LEDs, the possibility of failure is higher.
It is worth noting that the voltage required for parallel connection is lower, but due to the different forward voltage drop of each LED, the brightness of each LED is different, In addition, if one LED is short-circuited, the entire circuit will be short-circuited, and the rest of the LEDs will not work normally. If a constant current drive is used, the current distributed to the remaining LEDs will increase, which may cause damage to the remaining LEDs, but the use of constant voltage drive will not affect the normal operation of the entire LED circuit.
3. Mixed connection method
Hybrid connection is to use a combination of series and parallel methods. First, several LEDs are connected in series, and then connected in parallel at both ends of the LED drive power supply. Under the condition that the LEDs are basically consistent, this connection method makes the voltages of all branches basically equal, and the current flowing through each branch is basically the same.
It is worth noting that the hybrid method is mainly used in the case of a large number of LEDs. Because this method ensures that the LED fault in each branch only affects the normal lighting of this branch at most, which improves the reliability compared with the simple series and parallel forms. At present, many high-power LED lamps generally use this method to achieve a very practical effect.
4. Array method
The main structure of the array mode is as follows: the branch is composed of 3 LEDs, which are respectively connected to the Ua, Ub, and Uc output terminals of the driver output. When the three LEDs in a branch are all normal, the three LEDs light up at the same time; once one or two of the LEDs fail to open, it can ensure that at least one LED works normally. In this way, the lighting reliability of each group of LEDs can be greatly improved, and the overall reliability of the entire LED lighting can also be improved. In this way, multiple sets of input power supplies are required, and the purpose is to improve the reliability of the LED operation and reduce the overall circuit failure rate.
