Teardown of a Philips dimmable LED bulb

Posted on Thursday, August 31st, 2017 in Teardowns by DP


Kerry Wong did a teardown of a Philips dimmable LED bulb:

One of the first things you will notice about this light bulb is that the compact construction. Most noticeably the lack of the telltale heatsink fins. As a result however, the heat dissipation capability is greatly sacrificed. During normal operation when mounted pointing downwards without any airflow obstruction, the case temperature raised to above 60°C within a few minutes. I could only imagine what the temperature would be like when the light bulb is mounted facing upwards in a semi-enclosed light fixture.
So I decided to take it apart to see the what the construction looks like inside.

See the full post on his blog.

Check out the video after the break.

This entry was posted on Thursday, August 31st, 2017 at 3:47 am and is filed under Teardowns. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

2 Responses to “Teardown of a Philips dimmable LED bulb”

  1. Edward Knuckles says:

    Thank you for the very instructive video. I had no idea how they worked until your demonstration.

    From a mechanical engineering perspective the bulk of the heat generated by the circuit board and LEDs would best be removed to the environment through conduction to the metallic base that screws into the lamp holder. I suspect that there should be a heat conduction path from the metallic plate that the LEDs are mounted on and then to a flexible heat conductor inside the white insulating material that separates the LED mounting plate from the metallic base that screws into the lamp holder. Heat removal by radiation and convection through air currents around the light emitting portion of the bulb would be less effective than heat conduction through metallic components. Thus it would make much difference whether the bulb was pointed up or down. Whether or not my thoughts above are correct, it’s obvious that the circuitry required to make the LEDs functional are much more susceptible to heat damage than other types of bulbes.

  2. KH says:

    You give them too much credit. They are just spreading the heat around with the aluminum heat sink, I suspect they think it’s acceptable for a 7W design. To be sure, they aren’t going to maximize longevity for our sake. :-( Elevated temps is a design decision. Rather disappointed with Philips, they aren’t cheaply priced (but it seems they are cheaply made, ha ha.) But dying after two months and the rest over one year is indicative of a defective design. Or an evil OEM. Bad, bad Philips, it just kills my trust in them, but then most others can’t be trusted as well. Maybe Philips has been taken over by marketing types and bean counters, like Intel.

    I think you are too optimistic about E27 screw holders. I don’t think metals are touching in a lot of places, otherwise how would you unscrew it? Conducting area is actually not big, and the E27 holder is just thin metal, enclosed in plastic and thus is not really a good heat sink. There is only two not-so-thick wires to the E27 screw base. The main heat spreader is the aluminum cylinder, that’s all, ugly. Poor electrolytics and LED dies, must have been hellish in there.

Leave a Reply

Notify me of followup comments via e-mail. You can also subscribe without commenting.

Recent Comments

  • KH: TPS62200 will get him to under 15uA, a bit better than the 20-30uA he mentioned. I would try the same thing. Switch some resistors in...
  • KH: Yeah, it's an end-user thing. Very few people would spend hundreds of hours on this kind of project and sustain it. It's more or less...
  • Max: Not quite a dinosaur if you've seen Big Hero 6 though... wait. You've watched it with your kids, didn't you? That's cheating...! ;) One of...
  • Edward Mallon: A visiting researcher dropped by our humble basement workshop with questions about the physical skill level students would need if they added one of our...
  • KH: And that looks really expensive... Only browsed the vid though, I'm an dinosaur so I had the sound off too. Nice of him to open-source...