The eight mainly reason of led strip fault
The led damage from the improper package in transit
The false weld damage cause that pad has come off for shock in    transit
The welding tin too little cause that pad has come off
Adopt low quality of led strip PCB board , the led will break or come off when we bend the led strip
The copper foil and pad is separate when the bend angle is big on   install led strip, it also can cause led work break
The led strip is over-squeezed on install led strip, it cause damage to led ic(integrate chip)
The weld resistance layout too thick , so the weld tin can’t connect pad , the phenomenon belongs to false weld
When install led strip , please don’t bend the led strip, if the user over bend the strip will cause the pad of led strip come off

The method analysis and protect reason for led

The paper introduction of base concept of led ,the reason of damage and protect electrical circuit.LED base concept (LED is light emitting diode)is semiconductor it put the electrical energy into light energy , it adopt electrical to lit.base on analysis , the character of led is obvious , for example it has long service time, excellent efficiency , no radiation and low power,the optical spectrum almost focus into vision frequency channel , the optical efficiency can reached 80~90%,the high power is light power rate, in generally refer to 0.5W,1W3W5W or upper , lit angel refer to aggregate state of light  led protect,
In specify electrical circuit, we can using the protect circuit as follows,bypass protect, there are many branch is in led serial electrical circuit, we can add a PTC component to protect led in echo branch, this is method as high accuracy and stability
Protect led in generally
Add a PTC component to protect led in generally in echo group led. the advantage of solution is simply , the user was satisfied with the results of the method,
In summary , this paper has been introduction of base concept , the reason of damage and the method of protect led, first we talk about the led concept , then we has analysis that the reason of led damage,
finial we has been refer to some method to protect led. and we introduce electrical circuit of led. wish it is valid information for your led project.

Common LED constant currently

First we recognized LED, because of the led luminous is proportional the led forward currently. and the led structure determine the property of led heat dissipate. the led manufactory will provide detail data shell for user information .fox example Φ5 as 20mA, 1W as 250mA, those parameters not mean that the Led is constant currently device.

Now we start introduce the constant currently , the mainly component
is triode, the withstand voltage of triode should be over 400V, and the power should be over 10W, the radiator is necessary . the electrical circuit can load at least for a few triode. can reached ninety triode.

thought the cost is on the increase, but the affect is best than resister currently . the electrical circuit still output constant currently ,even the input voltage fluctuates largely, so the led have a position of advantage on server time. it can take work currently in constant status,

*The electrical circuit of constant currently
By the way we will talk that which is best way to current limiting both serial connection or parallel connection.
LED electrical circuit adopt serial connection or parallel connection, it is determine by require of design electrical circuit.
in serial connection , one of those led was in open circuit, and other LED will stop lit, one of those led was in short circuit , and other LED is nothing.

in parallel connection, one of those led was in open circuit, and other LED is nothing,
one of those led was in short circuit, whole circuit electrical is break , even the power supply will stop work or damage. the serial connection has certain advantage over the parallel connection.
connection just only to put a low input voltage to led. if each LED has different offset currently , so it will lit different luminous, it may cause uneven luminous.

Essentially, the serial connection can provide the guarantee of consistency currently for LED, but it is necessary of high voltage.
the sum of all led currently is total currently of electrical circuit,
so the sufficient power supply is necessary.

Strict speaking ,there are shortage in serial connection and parallel
connection. there is more to think about design circuit of LED. in fact application, we will adopt the array of serial connection and parallel connection. the resolution can overcome or reduce those shortage.

Furthermore, we also can using serial – parallel – serial connection.
the resolution can reduce influencing surface for a LED , and a few of high power resister become to dozens of low power resister , it is advantage of dissipate heat system, the led device is compactly layer out as a whole.

Using it to drive low power led, it has advantage that not afraid load short circuit, simply electrical circuit. a electrical circuit can drive dozens of led.

The leaking currently only has 100uA, when led can work properly , the led will open circuit ,there are transients in dc power supply .

The typical capacity down back of electrical circuit
We will check the driver electrical, we should carefully check electrically circuit whether correction or not , special check the position poly and negative poly of rectification bridge .

due to the capacity down back is not isolate power supply ,the electrical circuit has withstand high current impulse. also call it’s transients. the withstand high current impulse may damage the LED.
so using the temperature coefficient prevent the withstand high current impulse,
there are PTC(positive temperature coefficient and negative temperature coefficient in mainly device. we also can select transient voltage suppressor(simple to call TVS) using in your prevent electrical circuit.
The work theory of PTC(positive temperature coefficient) is that with temperature of electrical circuit board increase over to Medame curie’s point, the resister increase , it will cause current decrease .

The TVS(transient voltage suppressor) prevent damage of components in overvoltage.

Intelligence led constant current is a instance,

*The typical linear constant current source
We know that the power supply divided to constant voltage source and constant current source , the constant voltage refer to output voltage is stable , this mean is it would never be changed when output load is unalterable. the constant current source is which the output current is stable, this mean is it would never be changed when
output load is unalterable. the led is semiconductor diode , the property of volt-ampere is negative temperature ratio, the bigger input current will damage led when we adopt constant voltage source . so the constant current source will be the led best choice, the constant current source divided into switching power supply and linear power supply, following we will compare the advantage and disadvantage of both switching power supply and linear power supply.
advantage                           disadvantage
switching          High efficient(reach to 90%)         Low reliable , high cost

linear          High reliable , low cost               Low efficient (just only 85%)
*The efficient of linear constant current source
With input voltage increase ,the efficient of linear constant current source will decrease
the input AC as 110v, the efficient just only 85%
But the efficient would be become high when low input voltage normal working ,
The necessity of detail description of structure and property of linear constant current source.
Adopt the normal constant current diode to design linear constant source
We will analysis the led theory from voltage – ampere listing table as follows
Adopt the self-adapter to improvement of efficient of linear constant current source
There are resolution in linear constant current design
Because of the output load is LED , we know that the led is constant current load,
the quantity of led must meet input voltage , for example , suppose the input voltage is 300V,if a led forward voltage is 3v, one hundred led in serial electrical circuit is necessary , when input voltage increase , the forward voltage of led still maintain uncharged , the whole constant current source were to be reducedDo you have any resolution to sole that problem?

Adopt the self-adapter to adjust the quantity of led is best method, add the amount of led to led electrical circuit when input voltage is raise, to decrease the quantity of led when input voltage is fell.
*Character of intelligent led constant current
Self-adaptive input current
As description previous sections, the efficient can reached 99% when adopt the self-adaptive in electrical circuit. the efficient of constant current source still maintain 99% even the range of input voltage in consistent chang.
Self-adaptive temperature
When environment temperature was changed , the power of constant diode will raise ,
fox example the environment temperature raise , as the led forward voltage will fall base on LED voltage – ampere, so the voltage of constant current diode raise, power increase , the intelligent constant current source will add the amount of led to increase total voltage in serial electrical circuit, it can maintain high efficient for whole input voltage,

As see above picture, the environment temperature raise from 35 to 85, but whole efficient of input voltage almost no change , it still maintain over 98%
Self-adaptive of different forward voltage of led
The intelligent led constant current source has other function that it is self-adaptive of different forward voltage. there are different forward voltage of led in electrical circuit , the intelligent led system can automatic switch the amount of led , to guarantee whole efficient in 99%
Chang the amount of led will not change the luminous ,
If the resolution just only change the quantity of led , due to the current of constant current source not change , the total luminous will be change , we considers this problem, we will adopt the self-adaptive to solve the is problem, it can maintain whole power is not change ,

As see above picture , it adopt the self-adaptive after output luminous still maintain no change even in different range of input voltage