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I am working on a project for an LED lamp. We are trying to power it via a 3S lithouk ion battery pack delivering up to 12.6 V with a cutoff voltage of 9 V. The brightness of the LEDs at 10.5 V is the lowest we'd like it to be, so we're wasting half of our battery capacity.

Usually, I'd use a buck boost converter, but they are way to big to find into our lamp. I've seen some LED driver ICs but they all have more pins that I'm used to and I'm working how I could use them in the project. The total current consumption is around 1.5 A. Since the electronics are encased, they should not produce much heat.

The inner diameter of our lamp is 40 mm. We're using LED strips rated for 12 V.

What would be an ideal solution to turn a voltage range of 9 V-12.6 V into constant 12 V with high efficiency (low heat production) and on a small scale so that it fits into a 40 mm tube?

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  • \$\begingroup\$ Provide as much information about the 12 V LED lamp as you easily can. Chances are it already contains a "somewhat constant current" LED driver. For the LEDs, there is no advantage to having a constant voltage. \$\endgroup\$
    – greybeard
    Mar 20, 2023 at 8:11
  • \$\begingroup\$ LED-Strips rated for 12V Chances are each segment is just 3 "blue+phosphor" LEDs and one resistor in series. But measure what part of discharge you're actually losing - even with a nominal voltage of 11.1 V I'd guess less than one fifth rather than one half. (Alternatives include using a 4S LiFePO - 12.8 V nominal, ~11 V cutoff.) \$\endgroup\$
    – greybeard
    Mar 20, 2023 at 9:07
  • \$\begingroup\$ They are cob leds. The main issue is, as the voltage of the battery drops, the leds get dimmer. Around 10.5V the led strips are really dim, so the remaining capacity isn't useful for us :/ \$\endgroup\$
    – Hatschi
    Mar 20, 2023 at 9:10
  • \$\begingroup\$ (For a compact lamp, starting from LED strips is one odd choice.) \$\endgroup\$
    – greybeard
    Mar 20, 2023 at 9:11
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    \$\begingroup\$ Sounds relatively straightforward. Go to TI's web site and try their Webench to see some possible designs. \$\endgroup\$
    – Finbarr
    Mar 20, 2023 at 10:26

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