Introduction Of The Connection Method Of The Side Light-emitting SMD Led

- Jun 28, 2019-

The side-emitting patch LED is a light-emitting diode, which is a kind of decorative lighting product which is often used in the commercial and home lighting industries. It not only has the effect of lighting, but also is used for interior decoration due to its soft lighting. It can also adjust people's mood and ease people's pressure. Because the types and types of side-emitting patches on the market are very diverse, consumers should understand how to connect the side-emitting patches before buying. ?

How to connect the side-emitting patch led

First, the overall serial form

1, simple tandem form

Generally, the LEDs 1~LEDn in the series connection form are connected end to end, and the current flowing through the LEDs is equal. For the same-size and batch LEDs, although the voltage on a single LED may be slightly different, since the LEDs are current-type devices, it is possible to ensure that the respective luminous intensities are consistent, which is a simple series connection. The LED has the characteristics of simple circuit and convenient connection. However, due to the series connection, when one of the LEDs has an open circuit failure, the entire LED string will be extinguished, which affects the reliability of use.

2. Series connection with parallel Zener diodes

Each LED is connected in parallel with a modified series connection of Zener diodes. In this connection, the breakdown voltage of each Zener diode is higher than the operating voltage of the LED. When the LED is working normally, because the Zener diodes VD1~VDn are not conducting, the current mainly flows through the LED1~LEDn. When the LED string is damaged by the LED, the VD1~VDn is turned on, except In addition to the faulty LED, other LEDs still have current passing through and emit light. This type of connection is greatly improved in reliability compared to a simple series.

Second, the overall parallel form

1, simple parallel form

The LEDs 1~LEDn in the simple parallel form are connected in parallel at the beginning and the end, and each LED is subjected to the same voltage during operation. It can be seen from the characteristics of the LED that it belongs to the current type device, and a small change in the voltage applied to the LED will cause a large change in the current. In addition, due to the limitation of LED manufacturing technology, even the same batch of LEDs, the difference in performance is inherent, so when LED1~LEDn is working, the current of each LED is not equal. It can be seen that the insufficiency of the current distribution of each LED can cause the life of the LED with excessive current to be sharply reduced or even burned out. This connection is simpler. However, the reliability is not high, especially for applications where the number of LEDs is large, which is more likely to cause malfunctions.

2. Independently matched parallel form

For the reliability problem existing in simple parallel, the independent matching parallel form is a good way. Each LED in this mode has its own current tunability (driver V+ output is L1~Ln, respectively), ensuring that the current flowing through each LED is within its required range, with a good driving effect, a single LED When the protection is complete and the fault does not affect other LEDs, it can match the characteristics of LEDs with large differences. The main problem is that the structure of the whole driving circuit is complicated, the cost of the device is high, and the occupied volume is too large, which is not suitable for a large number of LED circuits.