How to solve the problem of LED light strip heating?

The most commonly used specifications for led strips are 12V and 24V. 12V is a 3-string multi-channel parallel structure, and 24V is a 6-string multi-channel parallel structure. Because led strips are to be connected, each strip is specific. How long can be connected, and the width of the line and the thickness of the copper foil have a great relationship with the design. Because the current intensity per unit area can be related to the cross-sectional area of the line, if this is not taken into account when wiring, the light bar will be over-current when the connection length exceeds the current that the line can withstand. The heat, while damaging the circuit board, also reduces the service life of the LED.

2. Production process problems:

Since the LED strips are series-parallel, when a short circuit occurs in a certain group of loops, the other LED voltages in the same group will rise, the brightness of the LED will increase, and the corresponding heat will increase. . The most obvious is that in the 5050 light bar, when the 5050 light bar is short-circuited in any one of the chip circuits, the current of the one that causes the short circuit doubles, that is, 20mA becomes 40mA, and the brightness of the lamp bead It will become very bright, but at the same time the amount of heat will increase dramatically, and the board will burn out in a matter of minutes. However, this problem is relatively concealed, and generally it is not very noticeable, because the short circuit does not affect the normal illumination of the light bar. If the employee in charge of the test only pays attention to whether the LED is illuminated, not to check the brightness abnormality, or not to do it. Visual inspection, only for electrical measurements, will often ignore this problem, which is why many LED light strip manufacturers always encounter customer complaints that the product is hot but can not find the reason.

Solution:

1. Circuit design: The loop should be as wide as possible, and the spacing between the lines is 0.5mm. The rest of the space is preferably full. The thickness of the copper foil should be thickened as much as possible without violating the customer's requirements for the total thickness of the circuit board. The thickness is generally 1~1.5 OZ.

2. Production process:

A /, when printing solder paste, try not to let the solder between the pads, to avoid soldering short circuit caused by poor printing;

B, avoid short circuit when patching

C. Check the position of the patch before reflow.

D. After the reflow, do the visual inspection first, make sure that the light bar is not short-circuited, and then do the electrical test review. When reviewing, pay attention to whether the LED is abnormally bright or abnormal after lighting.