Searching \ for '[EE]: delayed startup power supply' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/timers.htm?key=delay
Search entire site for: 'delayed startup power supply'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: delayed startup power supply'
2002\09\06@115654 by Bob Japundza

flavicon
face
I have been looking into some of the offerings TI has for supervisory circuits, with the idea if creating a power supply for my project that will delay startup.  However, I am not clear on how you could tie these devices into a regulator.  Basically, I would like to design a power supply that will shut down power to the whole board if any transients are detected and reset everything (lcd, eeproms, etc.) on power up. The design is going to be used in a homebuilt aircraft and I want my project to shut itself off when a transient is detected (starting the engine) and come back up automatically in a second or two after things stabilize.  Can anyone point me in the right direction?

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\09\06@235439 by Jim

flavicon
face
----- Original Message -----
From: "Bob Japundza" <spam_OUTBob.JapundzaTakeThisOuTspamREALMED.COM>
To: <.....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU>
Sent: Friday, September 06, 2002 10:56 AM
Subject: [EE]: delayed startup power supply


> I have been looking into some of the offerings TI has for supervisory
> circuits, with the idea if creating a power supply for my project that
> will delay startup.

Delay the application of the regulated DC for a second or two
after a request for "Power On" is received?

Sounds good.

I designed a power-on circuit for that Heathkit SS-8000 (which became
the SS-9000 with the subsequent addition of a WARC band!) that drove
the "main DC power relay" - the circuit quickly 'tested', then applied
DC to the radio in order to insure it was within an acceptable range
(and polarity!) before it allowed the relay to "close" and apply "DC
prime power" through to the rest of the radio.

> However, I am not clear on how you could tie these devices into
> a regulator.

Therein lies the rub - so let's set forth the design rules and
the rationale behind them first.

> Basically, I would like to design a power supply that will
> shut down power to the whole board if any transients are detected
> and reset everything (lcd, eeproms, etc.) on power up.

Sounds like you need (preliminarily):

 1) Pre-Brownout detect (maybe an 'early' detect that
    is meant for an NMI (a non-maskable interrupt to that
    signals an impending "power down" event)
 2) Brownout reset, occurs some defined time *after* 1) above
    and depends on system dynamics such as power supply cap
    reserve and it's ability to source unregulated DC for
    the regulator.
    Normally this signal in past days would stop system clocks
    and inhibit RAM write enable lines (if RAM was battery
    backed-up that is!), etc.
 3) The third event - remove the actual regulated DC from the
    device. Some regulators have "power down" control inputs,
    or, someting can be designed into existing designs. The
    easiest way is via relay or s series FET and simply remove
    "DC Prime (V batt) power input".

RF Jim

> The design is going to be used in a homebuilt aircraft and
> I want my project to shut itself off when a transient is
> detected (starting the engine) and come back up automatically
> in a second or two after things stabilize.  Can anyone point
> me in the right direction?
>
> --

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...