How to deal with LED light bar heating?

Update:03 Sep 2021
Summary: Analysis of the causes of heating of the LED light bar:1. L...
Analysis of the causes of heating of the LED light bar:
1. Line design issues:
At present, the most commonly used specifications of LED light strips are 12V and 24V. 12V is a three-string multi-parallel structure, and 24V is a 6-string multi-parallel structure. Since the LED light bar is to be connected and used, each type of light bar is specific The length of the connection is greatly related to the width of the circuit and the thickness of the copper foil when designing. Because the current intensity per unit area is related to the cross-sectional area of ​​the line, if this is not considered when wiring, then when the connection length exceeds the current that the line can withstand, the light bar will be caused by overcurrent. Heating, while damaging the circuit board, also reduces the service life of the LED.
2. Production process issues
Because the LED light bar is a series-parallel structure, when a short circuit occurs in a certain group of circuits, it will cause the voltage of other LEDs in the same group to increase, the brightness of the LED will increase, and the corresponding heat generation will also increase. . The most obvious thing is that in the 5050 light bar, when any chip loop of the 5050 light bar is short-circuited, the current of the short-circuited lamp bead will double, that is, 20mA becomes 40mA, and the brightness of the lamp bead It will become very bright, but at the same time the heat will also increase sharply, and in serious cases, it will burn the circuit board within a few minutes. However, because this problem is relatively obscure, it is generally not paid attention to, because a short circuit does not affect the normal light emission of the light bar. If the staff in charge of the test only pays attention to whether the LED is glowing, and does not check for abnormal brightness, or does not do it In appearance inspection, if only electrical testing is done, this problem is often overlooked. This is why many LED light bar manufacturers always encounter customer complaints that the product is hot, but they can’t find the reason.
LED light bar heating problem treatment:
1. Circuit design: The circuit should be as wide as possible, the spacing between the circuits should be 0.5mm, and the rest of the space should be filled up. The thickness of the copper foil is as thick as possible without violating the customer's requirements for the total thickness of the circuit board, and the general thickness is 1~1.5 OZ.
2. Production process: When printing solder paste, try not to allow solder connection between the pads to avoid solder short circuit caused by poor printing;
3. Avoid short circuit when patching;
4. Check the placement of the patch before reflow; do visual inspection after reflow to make sure that the light bar is not short-circuited, and then recheck the electrical test. When rechecking, pay attention to whether the LED is abnormally bright or abnormally dark after it is lit.
The use of LED flexible light strip
The LED constant current used by the LED light bar is 20mA. Therefore, the current supplied by the power supply must be guaranteed not to be greater than this constant current. Many friends only pay attention to the voltage when using it, and ignore the current specification. This often leads to the breakdown of the LED due to the excessive current of the power supply, causing damage to the LED strip.
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