Led common factors of damage and protect the led circuit method

Some leds in the use of all kinds of causes in current increases, this time if you don't take protective measures, so the increase of current exceeds a certain amount of time and amplitude after the led will be damaged. So let's understand the specific cause of the damage of the LED.

The failure reasons of the led mainly include:

1. The voltage jump.

2. A component or printing lines or other short circuit of the wire and form LED the local short circuit of the power supply channel, make the place of higher voltage.

3. The LED damage and thus form a short circuit because of their quality reasons, its voltage drop is passed on to other leds.

4. Within the temperature too high, the characteristics of the LED go bad.

5. Internal into the water, water is conductive.

6. When not doing a very good job of anti-static, inside the LED has been hurt by the electrostatic. Although is normal voltage and current value, is also easy to cause damage to the LED.

The LED damage to understand the above factors. So, how should I proceed with LED circuit protection?

To protect the LED circuit method is as follows:

1. Led circuit adopts fuse (tube)

Due to the fuse is a one-off, and slow response, poor effect, use of trouble, so the fuse is not suitable for LED lighting products, because leds are now mainly in the city of light engineering and lighting engineering. It LED protection circuit to very demanding: beyond normal use can immediately start, when the current protection, make the LED

Power supply channel is disconnected, the LED and the power can be protected, and automatically restore power after the whole lamp normal, does not affect the LED work. Circuit cannot too complicated volume cannot too big, the cost is still lower. So it's very hard to adopt the way of fuse implementation.

2. The transient voltage suppression diodes (TVS)

Transient voltage suppression diode is a diode in the form of highly efficient protection device. When it's poles reverse transient high-energy shock, at 10 to the minus 12 power seconds the speed of a very short time, make yourself between the poles of reduced to low resistance, high resistance to immediately absorb up to several kilowatts of surge power, voltage clamping yuan between the poles

In a predetermined voltage value, the effective protection of precision components in the electronic circuit. Transient voltage suppression diode has a fast response time, the transient power, low leakage current, breakdown voltage deviation good consistency, clamping voltage control more easily and without damage limit, the advantages of small volume.

But in be used actually found to find required voltage value of TVS device is not easy. LED light bead damage mainly because too ambassador chip internal electricity due to overheating. TVS can detect over-voltage cannot detect overcurrent. To choose the appropriate voltage protection point it is difficult to grasp, this device won't be able to produce it

In practice, however, difficult to use.

3. Select the restore the fuse

Since the recovery fuse is also known as polymer positive temperature thermistor PTC, is made up of polymer and conductive particles, etc. After special processing, the conductive particles in the polymer of conductive pathways. When the normal working current through (or components are in normal temperature), PTC self recovery fuse in low resistance state;

When the circuit has the abnormal through the current through the environment (or temperature), large current the heat generated by the environment (or temperature) make polymer rapid expansion, is cutting off the conductive particles form conductive pathways, PTC self recovery fuse in high impedance state; When the circuit through the current (overtemperature condition) disappears, polymer cooling, volume

Again back to normal, the conductive particles conductive path, PTC self recovery fuse and the initial state of low resistance. In normal working condition since the recovery insurance tube heat is small, the abnormal working state of its high heat resistance is very big, also limits the current through it, so as to play a protective role.

In the specific circuit, can choose:

(1) shunt protection. The LED is usually divided into many concatenated branch. We can add a PTC component is in front of each branch, respectively, for their own protection. This approach has the advantage of high accuracy, the reliability of protection.

(2) the overall protection. In front of all the light bead added a PTC components, to protect the whole lamp. The benefits of this way is simple, does not occupy a volume. For civilian products, the protection in the actual use of the result is satisfactory.

This paper first introduces the basic concept of LED circuit, LED the cause of the damage and LED circuit protection method of sharing, first to understand the basic concept of LED circuit and analyzes the causes of damage of the LED, LED circuit protection method is proposed in the end. Share the use of fuse and suppress diode, etc., can achieve the LED circuit protection.