From: mike brown <mike@n5qmg.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Mon, 27 Apr 2020 10:50:21 -0700
Subject: Re: [EE] Voltage regulator with high input voltage
Thread-Topic: [EE] Voltage regulator with high input voltage
Thread-Index: AdYcvX1UKqORKUqUQT+lONDbw7zRHQ==
Message-ID:
 <CADHfTmMwqLkrA-uBVBfx7T1q+j4o-Kn1Lb_5PsUC1Xn6R-ExDg@mail.gmail.com>
References:
 <CAFo_nNp2c_0B6MP+Nv9OJBwjbo5QokUdgM8xL4zgSZAeYSXbOw@mail.gmail.com>
	<CADOftedynRRY0egLmdaThcf4m+wVco2H16OdoFwhZRK-vpUg1g@mail.gmail.com>
	<CAB115wFRXGysEZcR-=Gfp=B26Co6nsJoUAdbua+3_3DQ2m91vA@mail.gmail.com>
In-Reply-To:
 <CAB115wFRXGysEZcR-=Gfp=B26Co6nsJoUAdbua+3_3DQ2m91vA@mail.gmail.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: None (protection.outlook.com: n5qmg.com does not designate
	permitted sender hosts)
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=n5qmg-com.20150623.gappssmtp.com; s=20150623;
	h=mime-version:references:in-reply-to:from:date:message-id:subject:to;
 	bh=iwg7wmkip+UVg+WJPq+vmB9/aAJVWX9Fq4qannED/BQ=;
	b=du7czdBSlkPFEu3OSHq0cdeldNbpgLjoONa+OXMzSpmp5bwfXW9fBroBPrkw74EN0L
	lrg5z/uyQiXM3ZVTNhv7AcXdSgIZdyeg9x2lgqp8xM/Pmv6hgtqyI64jfrC3X6Xne7yA
	/ki7Jcr5s9TGQXt4FLftH5X+fv2gTWfnV7QpwRbN7IIfxUW1IiGFf0SWdeJUCQ7IHZIt
	BSOenns0DdIQwxfX+Mb2WbDeENbVV5Rc4TrP8EMBsWjTYluqZE8NSzIAbslul4EmqdTd
	E7KQjFg9ZjdUrd4WvUm7lS7fyiET0IH8BCoFQ1LeiFifFrX4RiNoN/UJriyXBcSfLGs/	awAg==
authentication-results: spf=none (sender IP is 209.85.208.174)
	smtp.mailfrom=n5qmg.com; mit.edu; dkim=pass (signature was verified)
	header.d=n5qmg-com.20150623.gappssmtp.com; mit.edu;	dmarc=none action=none
 header.from=n5qmg.com;
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-received: by 2002:a2e:9842:: with SMTP id
 e2mr14995287ljj.273.1588009833455; 	Mon, 27 Apr 2020 10:50:33 -0700 (PDT)
x-topics: [EE]
x-content-filtered-by: Mailman/MimeDel 2.1.6
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

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 transients
> 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*
> > > --
> > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > > View/change your membership options at
> > > http://mailman.mit.edu/mailman/listinfo/piclist
> > >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.