12 V regulator

[Steve.Flanagan at VerizonWireless.com]

Bob

Let me re-state my requirement to clear up the request.

The regulator needs to supply an Input voltage of 12 Volts (+/- 15%) to the
time delay relay.
And must be good for a normal 12 volt auto configuration, and also a 16 volt
racing battery application.

So lets just say the regulator should be able to do the following:

Input 12 - 18 V
Ouput 12 Volts (1ma to 500ma)

If the input swings below 12 (ex 10.5) then it is ok for the output to also
swing to
10.5.  This is in case the 12V car battery goes a little low due to some
problem.

Steve

-----Original Message-----
From: rr [mailto:RRauscher at nni.com]
Sent: Monday, December 03, 2001 12:22 PM
To: diy_efi at diy-efi.org
Subject: Re: 12 V regulator



With the input voltage requirements spanning above and below
the output voltage requirements, the only regulator that will
operate correctly is a switching buck-boost combination.

BobR.


Steve.Flanagan at VerizonWireless.com wrote:

> I have a requirement for 12 V regulation (+/- 15% or a range of 10.2 to
13.8
> volts).
>
> My application is driving several 12V time delay relays (TDRs) and I am
> building it to work in a drag car that can be powered with 12v +
Alternator
> or a 16V system.  Keep in mind that with the 16V system, the battery
charger
> can put over 18V's.
>
> The TDRs pull as low as 1 ma each when in the off state, and as high as
200
> ma each when the relay is triggered.   So lets just say my requirements
for
> a regulator are:
>
> Input Voltage:  10v to 20v
> Output Voltage: 12v (+/- 15%)
> Output Current: 1mA to 500mA
>
> I tried to use a 12V regulator purchased from Digikey just as a test and
it
> seems to crap out at the lower current levels (I don't have the part
number
> handy, its at home, and this was a project I was working on over a year
ago,
> something just stirred up my memory that I never was able to resolve this.
> Originally I was not aware of the lower current levels, so the regulator I
> purchased worked in the 100ma range, but not at lower (1ma) range.
>
> Could someone recommend a very reliable 12V regulator that I can use to
meet
> my needs.
>
> As a work around I built my own regulator with a 12 V zener, resistor and
> 2n2222 transistor that seems to work, however, I am concerned about the
> reliability and heat issues with the 2n2222.
>
> Thanks,
>
> Steve F
>
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