From: Neil <picdude3@narwani.org>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Mon, 27 Apr 2020 11:05:32 -0700
Subject: Re: [EE] Voltage regulator with high input voltage
Thread-Topic: [EE] Voltage regulator with high input voltage
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I'd think 2-digit LED =3D 8 segs max @ a 10mA per seg =3D 80mA per digit. =
=20
(Multiplexed so one digit at a time).
And that's just 10mA.
Plus extra for uC, etc.

Cheers,
-Neil.




On 4/27/2020 1:50 PM, mike brown wrote:
> I'd say put a couple of blue or white LEDs in series to drop the voltage,
> but 100mA is fairly large current for that.  What kind of display is
> drawing that much current, and why?  I'm guessing either fluorescent
> display or LED backlit.  Can you leverage that in some way?
>
> On Mon, Apr 27, 2020, 12:41 David VanHorn <microbrix@gmail.com> wrote:
>
>> A buck switcher would be the way to go.  Input protection from transient=
s
>> might need to be added.
>>
>> On Mon, Apr 27, 2020, 11:33 AM Denny Esterline <desterline@gmail.com>
>> wrote:
>>
>>> It's a bit "long in the tooth" but I typically use the LM2576HV for suc=
h.
>>> 3A @ 60V input is a bit more than you'll need, but...
>>>
>>> Since you're doing a one-off, a PCB module might be something to
>> consider.
>>> Here's a $5 example https://www.ebay.com/i/303534088139
>>> Though I'm certain there are many, many more out there.
>>>
>>> -Denny
>>>
>>>
>>> On Mon, Apr 27, 2020 at 10:26 AM David C Brown <dcb.home@gmail.com>
>> wrote:
>>>> I am designing a current monitor for my e-bike.  Using an INA169 hi
>> side
>>>> current senor into a mid range PIC with a two digit LED display.
>>>>
>>>> Problem is getting the 5 volts for the PIC from the e bike battery
>> which
>>> is
>>>> nominally 36v but can rise to over 40 volts when fully charged.  Most
>>> small
>>>> linear regulators seem to be rated at 36v..
>>>>
>>>> Current would be a couple of milliamps with the display off (most of
>> the
>>>> time).  Nearer 100 with the display on..
>>>>
>>>> Any suggestions
>>>>
>>>>
>>>> __________________________________________
>>>> David C Brown
>>>> 43 Bings Road
>>>> Whaley Bridge
>>>> High Peak                           Phone: 01663 733236
>>>> Derbyshire                eMail: dcb.home@gmail.com
>>>> SK23 7ND          web: www.bings-knowle.co.uk/dcb
>>>> <http://www.jb.man.ac.uk/~dcb>
>>>>
>>>>
>>>>
>>>> *Sent from my etch-a-sketch*
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