LED has been widely used in lighting, decorative lighting products, LED lights in the design, the need to consider the choice of what kind of LED drivers, and LED as the load used in series and parallel, with reasonable design, to ensure LED work.
1, LED in series with all
LED driver output requires a higher voltage. When the LED consistency vary greatly, the distribution of the voltage across the LED in different different LED current through each of the same stars, LED brightness consistent.
When a short circuit when a poor quality LED, if we adopt the regulator-type drive (such as step-down approach commonly used in RC), the driver output voltage change, then the distribution of the remaining voltage across the LED will rise, the drive output current will increase, leading to easy to damage the rest of all the LED. If a constant current type LED driver, when a short circuit when a poor quality LED, due to the drive output current remains the same, all the LED does not affect the remaining work.
When a poor quality of an LED is disconnected, in series with the LED will not light all. The solution is in each LED at both ends of a zener in parallel, of course, turns on the zener voltage than the LED's turn require high voltage, or LED is not bright.
2, LED use of all parallel
Requires a large LED driver output current, load voltage is low. Distribution of the same in all the voltage across the LED when the LED is large difference in consistency, while the current through each LED is inconsistent stars, LED brightness is different. Consistency can be a good selection of LED, the lower supply voltage suitable for products (such as solar or battery powered).
When a poor quality one off pieces LED, if the use of stabilizing voltage LED drivers (for example, switching power supply regulator), the driver output current will be reduced, without affecting the rest of all the LED work. If it is a constant current type LED driver, as the driver output current remains unchanged, and distribution in the remaining LED current will increase, leading to easy to damage all the LED. The solution is as much as possible parallel LED, when disconnecting a one LED, LED current distribution in the remaining small, does not affect the remaining LED work. So do the parallel power type LED load, should not use constant current drives.
When a short circuit when a poor quality LED, then all the LED will not light, but if the larger number of parallel LED, the LED current through the short-circuit large enough to short circuit LED firing circuit.
3, LED using hybrid approach
The need to use more LED products, if all the LED series,
intelligent LED driver outputs will require a higher voltage. If all LED in parallel, you need a larger LED driver output current. LED series or in parallel of all, not only limits the use of LED and parallel LED load current is high, the cost of the drive will greatly increase. Solution is the use of hybrid methods.
The average number of parallel LED strings, distributions in a string of LED the voltage on the same stars through each LED with a string of almost the same on the current, LED brightness consistent. At the same time the current through each LED string is also similar.
When a series of poor quality LED has a short circuit, regardless of the driver or the constant flow regulator-type drive, which is equivalent to missing a string of LED, the current through the LED string will be greatly increased, it is easy to get damage to the string of LED. This large current through the string of LED damage, due to the current through the larger, more performance for the circuit. After a string of LED off, if we adopt the regulator-type drive, the drive output current will be reduced, without affecting the rest of all the LED work.
If it is a constant current type LED
display driver, as the driver output current remains unchanged, and distribution in the remaining LED current will increase, leading to easy to damage all the LED. The solution is as much as possible parallel LED, when disconnecting a one LED, LED current distribution in the remaining small, does not affect the remaining LED work.
There is another way of hybrid connection, that is, the average distribution of LED, the packet in parallel, then each series together.
LED quality is poor when there is a short circuit, regardless of the driver or the constant flow regulator-type drive, the LED in parallel in this way will all off, if it is a constant current type LED driver, the driver output current is unchanged, except for Parallel to this in the short-circuit LED parallel branch, the rest of the LED work. Assuming the number of parallel LED more drives larger drive current through the LED current Fengyun will increase short-circuit, high current through the LED Fengyun short, it is easy to become a circuit. As more parallel LED, LED off a slip road parallel to this, the average distribution of current is small, can still work, what What the LED lights, only one LED does not light.
If you drive by stabilizing voltage, LED poor quality short moment, the load is very small LED in parallel all the way, add the remaining voltage on the LED increases, the drive output current will be greatly increased, most likely damage immediately all LED, lucky, only this firing circuit short circuit LED stars, the drive output current will return to normal, the parallel LED more, this LED off a parallel branch, the average distribution of current small, can still work properly, the LED lights which Mody , there was only one LED does not light.
Through the above analysis, the drive and load LED series and parallel with the selection is very important, constant flow-driven power type LED is not suitable for the load in parallel, the same, the regulator-type
LED driver series with the load is not suitable for use. Guangzhou Shun technology companies have engineers designed, perfect production, to create first-class LED driver.