From: John Lawton <piclist@jle.co.uk>
To: "piclist@mit.edu" <piclist@mit.edu>
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Date: Mon, 20 Apr 2020 03:42:46 -0700
Subject: Re: [EE] LDO reg keeps failing. Looking for suggestions.
Thread-Topic: [EE] LDO reg keeps failing. Looking for suggestions.
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Indeed, on braking or reversing the energy generated by the motor may=20
raise the supply voltage greatly unless there is some means to dissipate=20
it. If the supply was a battery then probably not a problem.

Do you really need an LDO, or at least choose a regulator with a much=20
higher maximum input voltage to protect against input voltage transient=20
overload. The good old 7805 is robust and tolerates up to 35V, rather=20
more than the one used.

John

On 20/04/2020 11:01, Forrest Christian (List Account) wrote:
> I was just going to suggest that as it isn't there.
>
> Diode across the regulator 'pointing' at the input (Vcc) is the correct
> direction.
>
> I'm also wondering about the reverse body diode in the top fet couping em=
f
> into Vdd which would cause it to rise somewhat.   I don't know enough abo=
ut
> your motors to know if this is a possibility or not.
>
> On Mon, Apr 20, 2020 at 3:58 AM RussellMc <apptechnz@gmail.com> wrote:
>
>> On phone.
>> Can't display diagram.
>> Is there a reverse biased diode across regulator from input to output
>>
>>
>> Russell
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