0.9V- Boost Driver for White LEDs

[COMMANDR]

Interesting new white LED driver I just ran across, what do you think.

0.9V- Boost Driver for White LEDs PR4401/4402

The core of this driver consists of a step-up converter with current output, which provides an output voltage of typically 3.6 V for white LEDs. The input voltage can be as low as 0.9V, thus allowing a single cell battery operation.

For operation of up three LEDs is only one external component needed, which is an inductor. It is recommended to use an inductor value of 22 µH for a maximum battery lifetime ( more than 70 hours with an AA alkaline battery). With a 10 µH coil higher currents can be reached for maximum brightness of the white LEDs. The battery current will be reduced to less than 10 µA in case that the supply voltage drops to avoid a deep discharge of the battery.

Two different versions are available, the PR4401 offers a maximum current of 22mA, the PR4402 drives up to 40mA. Both versions are delivered in a compact SOT23-3 package, for size-sensitive applications also chip on board assembly is possible. Both LED drivers offer a low-cost three-component-solution for example for small LED flash lights or torches.





http://www.globalspec.com/Supplier/Profile/PREMASemiconductor/



Look under Product Announcements


Gary

 

[billw]

More on the prema web site here: http://www.prema.com/Application/whiteleddriver.html
(includes a real datasheet, and a pretty good one at that.) Efficiency is so-so (70%)
Alas, it sounds like one of those companies whose products never appear to the hobbyist marketplace.
Perhaps they'll talk to large volume flashlight manufacturers, although it's hard for me to imagine
that the one-cell 5mm white LED flashlight market is "in need" of another driver circuit.

 

[cage]

This accepts much lower voltages and is cheap to build:
http://www.emanator.demon.co.uk/bigclive/joule.htm
And here is something even more interesting, a single cell 1 watt led driver:
http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1094,P10995

 

[Doug S]

The datasheet itself is here:
http://www.prema.com/pdf/pr4401.pdf
While it has some degree of current regulation I don't care for the typical application circuit where the LED is hit with high current pulses rather that something approaching constant current. Later in the datasheet it discusses adding a diode and capacitor for current filtration but apparently the IC behaves badly if you add enough capacitance to really do the job.

 

[Martin]

The September issue of ELEKTOR will include a little LED driver PCB with the PR4401 and inductor on !
Read the details here.