If you have one of these then you may wish to either stop using it or completely change the way you use it. At the very least, wear insulated gloves and make sure the unit is unplugged after use. Do not rely on the onboard switch.

There are safer units available that convert the incoming power to an isolated and current limited supply, but this one pretty much puts full mains voltage straight out.

The bizarre LED dangling through a ragged hole in the ungrounded case may actually be a crude FUSE! Because if the positive lead touches grounded metalwork there will literally be a dead short, with just the internal rectifier and the LED in series with the mains supply. LEDs do actually make surprisingly good fuses due to having a microscopic encapsulated bond wire. They do sometimes blow in half though… Sadly, the LED will not save you from electrocution. It takes much less current to kill a human than to blow an LED bond wire.

Technically speaking they could have made a marginally safer unit by putting a capacitor on each leg of the supply and limiting the current to a much lower level. Even high power resistors could have been used for that. It would still pose a shock risk, but with much less chance of being fatal. But for a proper reliability test on a faulty LED panel a higher current may be useful.

Last Updated on December 4, 2022 by Swagatam 266 Comments

The post elaborately explains how to build a 3 simple LED bulb using many LEDs in series and powering them through a capacitive power supply circuit.
https://www.homemade-circuits.com/how-to-make-led-bulb-circuit/

This video was supposed to be about one version of the bulb/lamp, but it turned out that the box had two different bulbs in it, so it became a double teardown.
One oddity is that the resistor I thought was 510K is actually 5.1 Megohm, which is an unusually high value.

IKEA seem to have stuck with buck regulators for their bulbs which is strange in this era of cheap linear regulators. I’m not sure if there’s a significant efficiency advantage of using a buck vs linear regulator. But it may keep some of the heat away from the LED panel.
I think I prefer the simplicity of modern linear regulators with their single smoothing capacitor and no high frequency noise.

As with most IKEA products I’d guess they are designed with a bias to lasting longer than products from other brands.

The 6 pin buck regulator with built in rectifier is new to me. It makes sense, and also benefits from a wider pin spacing for better electrical separation.

The higher power lamp is the only one that is easy to hack for a lower output and massively longer life. The hack would involve removing one of the very low value sense resistors. I removed the 8.2 ohm resistor and the power dropped from 6W to 2.3W. Removing the 12 ohm resistor instead would give closer to 3.5W.

If attempting to open lamps in the way I did in this video, be aware that there are still glass ones in use, so take care to make sure the cover is soft plastic before attempting to squeeze it to release the adhesive. Also be aware that once the cover is removed it exposes live connections on the PCB when powered.

I’m not sure how much more streamlining they can do to a WiFi lamp that offers tunable white and RGB colour mixing options. It’s basically a power supply, Wifi module and then a rather spectacular I2C serially controlled five channel linear regulator.

As with all products like this, running them at a lower power setting will result in much less heat and significantly longer operational life. The biggest factors in lifespan will be LED reliability and heat related aging of the electrolytic capacitors.

It’s probably worth mentioning that the linear regulators used in these lighting products probably have other applications too. They are designed to operate over a wide voltage range, so should be suitable for low voltage projects as well as mains voltage use.

Although branded Eveready there was an Energizer sticker on the WiFi module. I’d guess this is a product from one of those companies that buys up dead brands for their status.

The Bright Power buck regulator is quite neat too. It’s a very standard approach to providing a low voltage supply, and there seem to be different versions for different voltage ranges, with each chip having two voltage options that can then be cheated higher with a zener diode in the feedback path.

Not sure the purpose of the mystery capacitor. I’d guess it’s a low value and intended to remove a bit of switching noise from the buck regulator.

Given the functionality of the light the circuitry is surprisingly uncluttered and minimalist. That’s entirely down to the very modular approach.