From: James Burkart <james@burkartstudios.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Mon, 20 Apr 2020 00:06:24 -0700
Subject: Re: [EE] LDO reg keeps failing. Looking for suggestions.
Thread-Topic: [EE] LDO reg keeps failing. Looking for suggestions.
Thread-Index: AdYW4+uLjB1P2Fv2QUa12erpgjfHPg==
Message-ID:
 <CAL271=2xg7ZS-pDHSv37VPDBOxh_sJu5YT0rgoQY-B3mC0YtKA@mail.gmail.com>
References:
 <CAL271=21XBEBxhFe21o48=uJA_GOBAvvp+Mftr6Mh+4Z7W1dcQ@mail.gmail.com>
	<CAB115wGh==-9XNXxiVYUXQsSiRRBxiMyYupmQEjGcrkzvNwqeQ@mail.gmail.com>
In-Reply-To:
 <CAB115wGh==-9XNXxiVYUXQsSiRRBxiMyYupmQEjGcrkzvNwqeQ@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: burkartstudios.com does not
	designate permitted sender hosts)
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=burkartstudios-com.20150623.gappssmtp.com; s=20150623;
	h=mime-version:references:in-reply-to:from:date:message-id:subject:to;
 	bh=+jg1rt8MX1YOALkq0lEgWAUAI1pmlL0fynnAtyojbzw=;
	b=qoZbu+C31Y4mHLWoVDl+h0lxatvpTXU7vKeLQ686VJckIkltZy6XLg5PTgAmd7smPT
	7u3hMtpqRqMfuGzfxs6QR75uzeChJW35Pablhy1KHYa8uoqJ6ld84lcEuHXC26hnMUG/
	shRG0lpjYrmHUBbHj0NSgmTaDjAZO+YQMOhX/m5m2ct7q+3cmMOL91EkJ5eSUi3u0/v+
	9N/BInWfaMd7Q3aqZmEWpp/fe9QSPkiC1gPOQMAuwxvPtwfrmFbFJ5/lpl6ACV9diWn0
	eiXfp8qSfuO26briruikEip5CWaECxKu5aigctZf8kdOWngHzi2QBrv2w7xIDR0IUdTd	1yIA==
authentication-results: spf=none (sender IP is 209.85.167.51)
	smtp.mailfrom=burkartstudios.com; mit.edu;	dkim=pass (signature was
 verified)	header.d=burkartstudios-com.20150623.gappssmtp.com; mit.edu;
 dmarc=none	action=none header.from=burkartstudios.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:a05:6512:3081:: with SMTP id
	z1mr9579543lfd.102.1587366395891; 	Mon, 20 Apr 2020 00:06:35 -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

VDD is 5V, and it's provided by the LDO regulator. VCC is the battery
voltage and is anywhere from 6.5 to 8.2V. I don't know what circumstances
would lead to VCC dropping below VDD. Could you shed some light on this?

On Mon, Apr 20, 2020, 12:25 AM David VanHorn <microbrix@gmail.com> wrote:

> If vcc can rise above the input then most pnp regulators will fail
>
>
> On Sun, Apr 19, 2020, 11:44 PM James Burkart <james@burkartstudios.com>
> wrote:
>
> > Hey everyone! Here's a little motor driver board I made that works grea=
t,
> > until it doesn't. The voltage regulator keeps failing on me. I've used =
a
> > couple different LDO regulators and it always happens. It's always at
> > random times. So I am pretty sure it's EMI from the brushed motors. If
> > someone here has a few minutes, could you look over my schematic and
> > recommend changes?
> >
> > The board is powered from a 2S lipo, so 6.5 to 8.2V. For the flywheel
> > output there are 2 motors in parallel that draw about 3A total when
> > running, and a stall current of about 20A. The pusher output runs 1 mot=
or
> > that draws about 100mA with a stall current of about 3A. I do use PWM t=
o
> > control the speed of the pusher motor.
> >
> > If you're wondering, this driver board is for flywheel Nerf blasters.
> >
> > --
> > Sincerely,
> >
> > James Burkart
> > *925.667.7175*
> >
> > *Schematic:*
> > https://drive.google.com/file/d/1dgLf3sFNzFxvEuzaqTuIHd4_VSUfNbg8
> > --
> > 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
.