Step-up led driver

I’d like to see a step-up led driver in the shop. Right now there are only step-down drivers in the shop. They work, but are not very useful when only 5V or even less are available.

I’ve made some simulations with the LT1618. Depending up on inductor and output capacitor selection it should be able to drive these leds:

1x 3W luxeon star, supply voltage as low as 3V
3x 1W luxeon star in series, supply voltage 3V
1x 12V white LED bar, supply voltage 5V
2x 12V white LED bar in series, supply voltage 5V

The circuit supports dimming with either a potentiometer or PWM input from a microcontroller. It also supports over voltage protection and can be used as a step-up adjustable voltage source with current limitation for other jobs.

Here’s the link to the website + LTSpice model: … 1061,P2079

I did my simulations with this circuit:

Current sensing is done with R1 = 0.05V / I(peak)
The maximum output voltage is Vout = (R1/R2+1)*1.263V

I’m asking if there’d be demand for something like this and if seeedstudio might consider making it. I don’t have time right now for designing the PCB ;-(

I put this in my outlook task since Aug, but didn’t have time to work on it yet… Sorry.
Maybe we will integrate it into other designs, thanks for the suggestion!

I’ve built this circuit now and it works quite well :wink:

It starts to work at about 2V and the 12V LED bar turns on already. Not 100%, but it’s not bad. With 4.3V it can drive the LED bar at full current. Soldering MSOP10 is quite terrible.

And a terribly directed >>video<< on flickr. I hope everybody can see that.

:smiley: It’s a nice work , I would like to make this board long time ago ,but it’s so busy that we cannot put it into our schedule .

^^ May be I could do it in the weekend . If I finished it that I will sent you a prototype.