1-cell/2-cell NiMH led driver

Hello,

You all must think.. another topic about led drivers?.. Well, the problem is that I'm looking for a led driver that can operate from very low voltage. I want to run it on 2 (or even 1) NiMH cells, so lets say 1,8-3,2v.

The led I want to use is a Cree XM-L, (3A, ~3-4v=) but this is not definitive

I've already found the LTC3490 but this thing can only deliver up to 350mA. The sense resistor is internal, so an external fet is no option here.

Do you guys have an idea for a led driver? Ready made is also possible.



greets,

Stefan

How low is your 'very low voltage'?
What are the voltage and current specs of the LED?

I've got a lot of 10 Ah NiMH D-cells kicking around. I want to run a led on two NiMH cells, so the voltage will be 1,8-3,2V.

The led is a Cree XM-L led (about 3-4V, 3A max), but this is not definitive since I just want to make a bright flashlight.

The disadvantage of the Cree XM-L led is that the voltage can be higher, equal or lower than the battery voltage, so a lot of smps-topologies are not suited for my application.

Try Intersil. Maybe something like this.

https://www.intersil.com/en/product...lators/integrated-fet-regulators/ISL9112.html

I have an UltraFire flashlight that looks like it has a Cree (or a copy) high power LED. It operates from a single AA alkaline, Ni-Cad or Ni-MH cell.
It can be focussed from a wide beam to a narrow beam. It has a metal case.
It was very inexpensive (a few dollars) on E-bay and shipping from China was free.

ronv said:

Try Intersil. Maybe something like this.

https://www.intersil.com/en/product...lators/integrated-fet-regulators/ISL9112.html

Click to expand...

This makes me happy

But can I put it in constant current mode?