原创 Analysis on LED open circuit protection device PLED06B

 2013-9-3 15:53  943 7 7 分类: 消费电子

Analysis on LED open circuit protection device PLED06B

1. LED open circuit protection scheme shows as below:

1. Why using LED open circuit protection device?

High power LED (such as 1w,2w, 3w ) has the characteristics of long service life, low power consumption and low maintenance requirements, so it is increasingly used in outdoor.

However, LED is sensitive electronic equipment. Overvoltage and transient over-current caused by system switching , electrostatic discharge and lightning will result in LED damaged.

In addition, switching Power Supply used in LED does not provide inductance ballast transient protection for lighting applications

2. Disadvantages of led series circuit

Usually, in 5 to 20 led series circuit. When one led fails open out, the entire led series circuit will stop working.

When used in the street or airport runway, a problem happen in the led array caused the light dimming or no lighting,resulting in security risks. Or shadow zone in the outdoor LED billboard will also caused losing money. In any circumstance, any problem in Led array will cause high maintenance cost.

3. Applications for LEIDITECH PLED06B device

For LED street light, outdoor LED billboard and so on.
Leiditech PLED series devices are often used for high power LED integrated circuit.

PLED device connect in parallel with each LED in LED arrays. When one Led fails open out , PLED device provide a switching electronic shunt path. This ensures the entire array of leds will continue to function even if a single led in the array does not.

When LED lamp regularly work, paralleled PLED device only pass several current, so it wont affect the entire circuit. When connect, the device will load all current in the led array and will cause 1.3V voltage.
PLED device help to protect the LED from the lighting and ESD surge caused by electrostatic. In addition, the reverse current diode will protect the LED array when the power’s anode and cathode connected backwards

PLED device usually connect with each led, also can provide connect 2 or even 3 led lamps .This will help to lower the cost. But when a led has failed open out, more than 1 led will not work.

4. What are the differences compare with other IC protection technical skills

PLED device can provide LED open circuit protection. SCR will also provide this protection. But Zener diode does not provide ,Because the current of the LED array will let zener diode overload and shorten its using life.

PLED device provide the protection when the power’s anode and cathode connected backwards, But SCR and zener diode don’t have this protection.

PLED device and zener diode both protect from lighting and ESD, but SCR does not.

1. How to choose the right PLED device for your applications.

Below is the steps for choosing LEIDITECH PLED06B device for LED applications.

1) Checking VF,IF and LED connect methods.

2) Make sure the leds’ numbers for LED array, checking constant current of the power supply equipment and constant output voltage.

3) Based on following conditions to choose suitable VF, IF and PLED protection rate and PLED device.

31)The current of PLED switch must less than constant current.

32)PLED connected voltage must less than the constant output voltage of power supply equipment.

33)Select led array need each PLED device to protect the led numbers (one ,two or three). PLED6 will effect when the voltage is 6v, can protect one led; PLED9 will effect when the voltage is 9v, can protect two leds; PLED13 can protect 3 leds( note: one led has problem will cause two leds or 3 leds turn off)

4) Choose the suitable lighting environment and suitable package for PLED device.

5) Checking the environmental temperature for the PLED device. Provide good heat transfer condition if needed.

6) Thru testing on the shunt led to test the PLED device.

7) Checking step2 and step3 to make sure if there’s any problem.

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