I have part numbers and data sheets for a number of SMD 3 leaded boost 
conveter LED driver ICs. Most of Chinese origin. None that I have seen are 
TO92, but that's just a matter of packaging.

I can provide some part numbers and maybe web \sites if interested, but can 
derive as good a datasheet yourself as you may be able to get officially in 
many cases.

A few quick mentions: Some come in 3 or 4 or 5 pin variants.
Some have direct coil drive or external FET gate drive versions.

Ground
Power in / Inductor / power out to output diode (unless separate pin as 
yours has)
Ground
Chip enable  - less common  - usually active ho=igh so can also be used for 
low Vin cutoff.
Voltage sense (rare)

CE6360, CE9908A / HY3100 / VS077A, AY7530xx, eg A7530ER.
Zetex: ZXSC100,

There are two ways to do 3 pins.
One is to have a LED output pin and internal diode.

The nasty and usual way is to connect the LED directly to the 
inductor/Vin/LED out pin - LED is fged with pulses of high current.. Death 
for most modern LEDs if long lifetin\me is desired.
I pointed this out to Zetex as many of their ap notes show this method. They 
didn't answer ;-)

Zetex ZXLD381 is a ttpical example.
It's in SOT23-3 but coul as easily be TO92.
One cell operation (0.9V+)

Zetex ap notes here

    http://www.diodes.com/destools/

EUREKA:
http://www.lzmcu.com/uploaddir/porducts%20guild/aicall.pdf
Better  http://www.analog.com.tw/pdf/SG09Q1.pdf

AIC1638, AIC1639 AIC1642 seem to be what you want (not xxx2115) and are 
available on TO92.
AIC are Tauwanese - I've used some of their products and been duly impressed 
with the results.

Whether these products match you product in any way is another matter :-)


      R





----- Original Message ----- 
From: "Dwayne Reid" <dwayner@planet.eon.net>
To: "pic microcontroller discussion list" <piclist@mit.edu>
Sent: Thursday, December 17, 2009 1:05 PM
Subject: [EE] to-92 LED driver


> Good day to all.
>
> I recently purchased a LED flashlight that runs from a single 1.5V
> "AA" cell.  Upon disassembling it, I see a total of 3 electronic
> components: the LED, a 10uH axial inductor and a 3-legged to-92
> device labelled "TX2115".
>
> I haven't yet tried to measure output current or efficiency but hope
> to do so soon.
>
> My Google search for "tx2115" turns up only one close hit: a Chinese
> site showing that part number and describing it as a Boost LED
> driver.  But: the picture is for a 4-legged to-92 device, not 3-legged.
>
> Anyone have any idea where I might find a datasheet for this device
> and, better yet, where to purchase them from?
>
> Thanks!
>
> dwayne
>
> -- 
> Dwayne Reid   <dwayner@planet.eon.net>
> Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
> (780) 489-3199 voice          (780) 487-6397 fax
> www.trinity-electronics.com
> Custom Electronics Design and Manufacturing
>
> -- 
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist 

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