Why did these chips burn out

------Question for BXRC-27E1000-B-03 Please Put your question below------

Hello @evmyairi,

Welcome to the DigiKey TechForum. Can you provide some additional details on your inquiry. Parts due fail for a variety of reason but knowing more about the circuit that they are placed in and the environment being used in can help to diagnose issues.

Thank you

Hello evyairi - welcome to the Forum community! Do you have a question about BXRC-27E1000-B-03?

We had some in ceiling lights we installed and after a year and a half they stopped working. And then we find out that the chip is discontinued. The light manufacturer couldn’t give us a reason why.

Hi evmyairi,

The reason LEDs and LED chip-on-boards like the BXRC-27E1000-B-03 fail is almost always due to running excessively warm. The hotter they run, the shorter their lifetime. The reasons why they might run excessively warm include any or all of the following:

  • They are driven at a high current rate (the higher the hotter)
  • They are not adequately heatsunk (prevents heat from dissipating rapidly)
  • They don’t use adequate thermal conductive interface between back of LED module and heatsink (prevents heat from efficiently transferring to heatsink)
  • There is inadequate airflow in installation (prevents heat from dissipating)

I can understand that being a commercial electrician for 50 years. When I took the chip of the heatsink it came right of the wire attached to the chip mst have been under a lot of heat stress because where it connected to the chip the chip connection dissolved. So yes heat was a big factor.The connection was friction based not a good tight connection. I see the new chips have a nice harness that clips in. My customer has 28 of these recessed fixture in his kitchen ceiling which is 27’ high. So replacing these trims was what was being done up until now. Because the chip was discontinued. So instead of replacing the whole trim we will replace the chip with the new one.

Hi @evmyairi ,

With your experience this may be stuff you’re already aware of but thought to share in case - if not for you, then for other readers.

A lot of time an incorrect LED driver is installed which may apply too much voltage or current depending on LED wiring configuration. Another thing to note is if they are wired in a parallel, or series-parallel configuration from a constant current driver that if one LED burns out, it will most likely destroy the remaining LEDs since they would be over-powered.

LEDs generally don’t prefer being inside luminaires as they hold in extra heat, so proper heat sinking is vital, especially in smaller luminaires. The luminaire acts as a heatsink, but many times, is not enough. The amount of heat generated in the wire connections doesn’t sound reasonable as I haven’t heard of wire connection issues with these which makes me question if something else is causing this. I’d like to take a look at your driver part number and the LED wiring configuration if you are able to provide them.

Assuming that your setup is correct, I did locate similar replacement LED COB options, click here.
Click here for additional Gen 7, Gen 8 options which do have higher operating voltage and/or current.

Scanning the QR code on the COB will provide further information on the LED which may include installation instruction.

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Sounds like a good idea. I’ll see if I can work something up. Thanks for your input.

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Here is two drivers. The one with the 35 watt output current is the old driver. This chip # 27E1000-B-22 is the chip that has been burning up. The driver they want us to change out to use with the new chip is the one with the 21 watt output current. My question is will the new 27E1000-D-73 work with the old driver.

The 700mA output current for both of these drivers is running at the absolute maximum current for BXRC-27E1000-B-03.

The LED modules aren’t going to be happy at that high of current and will not last long, which would help explain why the LEDs are burning out.

If that’s the LED you’re running you’re going to want a driver that is closer to 400mA. I don’t see any options with 0-10V dimming.

Here is a non-dimmable option, PN: 1866-3162-ND

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@Kristof_2649 is right on there. One should not drive an LED at it’s absolute max rating unless you have a very substantial heat sink and a fan blowing a lot of cool air over it. Using a 700mA driver in your application is negligence.

Also, as Kristof mentions, regardless of the power rating, both supplies are pushing 700mA through the LED. The power rating is just the max it can supply at the max voltage. In either case, the driver would be pushing 700mA across the LED, which will have a forward voltage in the range of 26V, which means there will be about 18W dropped across the LED.

Here’s a link to some supplies that I think might be more suitable.

If the “they” being referred to here is the manufacturer of the fixture in question, I would kindly ask that you share the manufacturer and model number of the fixtures with me via private message. To do that, click on a user’s avatar, then click “message”.

The initial driver selection followed by a suggestion to replace it with one that would do nothing to solve the problem suggests to me that there may be a lack of understanding on somebody’s part, which would be beneficial to get corrected.

As a note, in David_1528’s drivers link, if you need the 0-10V dimmable driver options, they will be listed as “Analog” under our Dimming attribute filter as per highlighted in blue below. Analog and 0-10V are interchangeable terms regarding dimming. To be sure, verify the drivers datasheet.

Related Topic:

LED Driver Dimming Types

Thank you. I will send some more pics of the lv panel that these fixtures are tied into. So even the new chip and the driver with 21 watts output is to high.

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Yes, we will also need to know your LED wiring configuration. I would find it hard to believe you have one driver per each LED. We will need the number of LEDs per driver, and how those LEDs are wired to the driver(s)

The new chip27E1000-D-73 so even the driver with the 21 watt output is running it to high. Here is a picture of the modules that these circuits are tied into the first one is still o-10v the other three modules replaced the other ones that were in there. So we are not getting 0-10v on the ones that are burning up.

Each fixture has its own driver so each driver has one led chip.

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Heat sink

Here is a written schematic of the circuit.

Hi @evmyairi ,

The schematic looks correct, you will only need to make sure you are using proper drivers to supply the correct constant current through each LED string, each driver with their own Analog dimming.

Here is a modified link of @David_1528 link of which only includes the analog dimming drivers.

-As far as continuing to use your Lutron drivers, unfortunately this is a product we do not currently supply or are able to support. However, I see that those are programmable, in which you should be able to set the drivers to a current and or voltage rating suitable for the LEDs.