Fill in your details below or click an icon to log in: You can follow along with the Glighter-S project on Hackaday. Later I learned about voltage, current, and resistance, and everything became clear. The tone of my post might not have suggested it, but I was really curious about the best ways to drive an LED. I saw this used as a trick that works also for red color and is sometimes used in the stop or low-beam rear light of some cars. Post as a guest Name.

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By using our site, you acknowledge that you have lrd and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dropout voltage is dependent on the converter maximum duty cycle among other things.

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LM (buck driver) dropout – Electrical Engineering Stack Exchange

You are commenting using your Twitter account. The LED have a 3. Datasheets typically give the maximum brightness when ped at high current for short periods of time at a low duty cycle.

Email required Address never made public. Moreover, the EMI could be fine with the board, but then appear with long wires and this, if present, is application dependent. By using our website and services, you expressly agree to the placement lde our performance, functionality and advertising cookies.


EE and firmware developer [Enrico] had played with LEDs as a kid, burning out his fair share of them by applying too much current. What is EMI like from 1 to 1. You are commenting using your WordPress. If you know something else or you can correct me, that would be awesome.

Coin-Sized LED Control | Hackaday

Notify me of new posts via email. I saw this used as a trick that works also for red color and is sometimes used in the stop or low-beam lm345 light of some cars. Inductor is not shielded and yeah, chip work on 1. LM buck driver dropout Ask Question. The datasheet does has guidance for this specific device on page 13 to calculate a more accurate duty cycle for given conditions.

He built a ton of safety features into it like short-circuit and open-circuit immunity, temperature control, and auto-off switching oed idle. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

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Coin-Sized LED Control

Email Required, but never shown. The regulator uses an external boost voltage of 3V from an LDO. One lm33405 datapoint is the most interesting for me: Many thanks for notice this! Leave a Reply Cancel reply Enter your comment here AFAIK, this over-current for short periods of time is related to efficiency: When I get access to some nice instrumentations I can perform some tests.


This is the first thing I check when choosing a buck regulator; some regulators have more complex issues such as minimum switch on and off times. When I was a kid LEDs were fairly new then, and expensivethe only way I could lee burning them out was by using nearly drained 9V batteries to drive them. You can follow along with the Glighter-S project on Hackaday.

The entire lm34005 of the LED board is copper, with a monster heat sink attached.

Every other power source caused them to heat up quickly and burn out. Moreover, the regulator have an oed Rsense on the drain of the MOS which is used to correct the feedback and it is NOT the external shunt resistorwhich can cause the drop, but I can’t find its value.