4 connection methods for LED drivers
Many LED products now use constant current driving methods to drive LEDs, and the connection methods of LEDs are also designed according to actual circuit needs. There are generally four forms: series, parallel, hybrid, and array.
1. Serial connection
The circuit of this series connection method is relatively simple, the ends are connected together, and the current flowing through the LED is very consistent. Since LEDs are current-mode devices, the luminous intensity of each LED can basically be guaranteed to be consistent. The circuit connection using this LED connection method is simple and convenient. But there is also a fatal shortcoming, that is, when one of the LEDs has an open circuit fault, the entire LED light string will go out, affecting the reliability of use. This requires ensuring that each LED is of high quality, so that the reliability is increased accordingly.
It is worth noting that if an LED constant voltage driving power supply is used to drive the LED, then when an LED is short-circuited, the circuit current will increase, and when it reaches a certain value, the LED will be damaged, causing subsequent LEDs to malfunction. All are damaged, but if an LED constant current driving power supply is used to drive the LED, when one LED is short-circuited, the current will basically remain unchanged and will have no impact on the subsequent LEDs. No matter which driving method is used, once an LED is open-circuited, the entire circuit will It won't light up.
2. Parallel connection
The characteristic of the parallel connection method is that the LEDs are connected in parallel from end to end, and the voltage on each LED is equal during operation. However, due to manufacturing processes and other reasons, even LEDs of the same model and batch specifications may not have the same current. Therefore, the uneven current distribution of each LED will cause the life of the LED with excessive current to be reduced compared to other LEDs, and it will easily burn out over time. This parallel circuit is relatively simple, but its reliability is not high. Especially when there are a large number of LEDs, the possibility of failure is higher.
4 connection methods for LED drivers
It is worth noting that the voltage required for parallel connection is low, but because the forward voltage drop of each LED is different, the brightness of each LED is different. If one LED is short-circuited, the entire circuit will also be short-circuited, and the remaining LEDs will not work properly. If an LED is disconnected, if constant current driving is used, the current shared to the other LEDs will increase, which may cause damage to the other LEDs. However, constant voltage driving will not affect the normal operation of the entire LED circuit.
3.Hybrid connection method
Hybrid connection is to use a combination of series and parallel connection. First, several LEDs are connected in series, and then connected in parallel to both ends of the LED driving power supply. In this connection method, when the LEDs are basically the same, the voltages of each branch are basically the same, and the current flowing through each branch is also basically the same.
It is worth noting that the hybrid connection method is mainly used when the number of LEDs is large, because this method ensures that the LED failure in each branch will only affect the normal lighting of this branch at most, which is more efficient than the simple series and parallel connection. reliability. At present, many high-power LED lamps generally adopt this method, and the effect is very practical.
4.Array method
The main form of the array method is: the branch is composed of 3 LEDs, which are respectively connected to the Ua, Ub, and Uc output terminals of the driver output. When all three LEDs in a branch are normal, all three LEDs will light up at the same time; once one or two LEDs fail and are turned on, at least one LED can be guaranteed to work normally. This can greatly improve the lighting reliability of each group of LEDs, and also improve the overall reliability of the entire LED lighting. This requires multiple sets of input power supplies in order to improve the reliability of LED operation and reduce the overall circuit failure rate.
