TL431 replacement with 1.2V reference???

On 1/17/2015 6:53 PM, whit3rd wrote:
> On Saturday, January 17, 2015 at 4:50:10 PM UTC-8, mike wrote:
>> On 1/17/2015 12:27 PM, mike wrote:
> [about low-V output limit of a SMPS design]
>
>>>>> All my wall warts use a TL431 as regulator.
>
>> Well, there's insufficient headroom for the TLV431 or the darlington.
>
> If you want, you can use the TLV431 to program a current mirror,  and
> drive the LED with the current mirror output, if this refers to the
> common TL(V)431/optoisolator feedback in an isolated switching
> power supply.
>
Sure, you can redesign the power supply.
Remember that with only 1.5V for the driver and the optoisolator,
it's not gonna be simple.
I chose the easier redesign with the NPN.  Works fine.

On 1/17/2015 7:14 PM, DecadentLinuxUserNumeroUno wrote:
> On Sat, 17 Jan 2015 04:18:49 -0800, mike wrote:
>
I thought I heard the sound of digging your hole ever deeper...
>> I need an MP3 player that runs 24/7.
>
>    You mislead folks here.  Nice ambiguity introduction.
Only thing ambiguous is your misinterpretation.
I stated my objective.
You're the only one who decided to wedge yourself into the thread to
force it off track.  100% denigration, 0% help...classic UNO.
>
>    "an mp3 player" usually refers to software on a computer, not some lame
> toy you were stupid enough to buy one of.
You're free to misinterpret whatever you want.  You're skilled at the 
task...might as well flaunt your strong points.
>
>> All the ones I have shut down and switch to file transfer mode when you
>> plug in USB.
>
>    Must be their OS.
Brilliant deduction!
>
>    Maybe you should develop a different procedure that does not invoke that
> problem.

You mean, like making a battery eliminator?

> Or buy a better device.

You linux trolls are big on buying stuff when what you have can't be
made to work on your beloved OS...and act like that's the way it should 
be.  This isn't about your beloved OS...not one little bit.

You just can't help digging deeper...
>
>> So, I think I need a 1.5V AAA battery eliminator.
>
>    This will abate the USB handshake mode change how?

For the third time, this is not about any OS handshake.
It's about the result of detection of 5V on the USB port of the device.

The battery eliminator lets me play the mp3s while AC powered...24/7
which was the objective and has been achieved.

When you're standing in the hole that you're digging...and you're filling
it with effluent...you should stop doing both.

But I do enjoy watching you tread effluent.

Have a UNO day.
I'm gonna sit back and listen to mp3s.

mike <ham789@netzero.net> wrote:
>I need an MP3 player that runs 24/7.
>All the ones I have shut down and switch to file transfer mode
>when you plug in USB.
>So, I think I need a 1.5V AAA battery eliminator.

>All my wall warts use a TL431 as regulator.

>If I could find a replacement with 1.2V-ish reference in TO-92
>I could just drop it in and change one resistor to get 1.5V.

>What's a good cheap, shunt-regulator IC that will go down to 1.5V?
Why not just use a LDO with 1.5 V output instead?

-- 
Dipl.-Inform(FH) Peter Heitzer, peter.heitzer@rz.uni-regensburg.de
HTML mails will be forwarded to /dev/null.

On 1/19/2015 5:56 AM, Peter Heitzer wrote:
> mike <ham789@netzero.net> wrote:
>> I need an MP3 player that runs 24/7.
>> All the ones I have shut down and switch to file transfer mode
>> when you plug in USB.
>> So, I think I need a 1.5V AAA battery eliminator.
>
>> All my wall warts use a TL431 as regulator.
>
>> If I could find a replacement with 1.2V-ish reference in TO-92
>> I could just drop it in and change one resistor to get 1.5V.
>
>> What's a good cheap, shunt-regulator IC that will go down to 1.5V?
> Why not just use a LDO with 1.5 V output instead?
>
Because it needs packaging.
Because it dissipates more power than I'm comfortable with if I
build it into a dummy battery.