Design Skills Test Question

Well, if SW1 is fed from ERCOT and SW2 from the Eastern Interconnect grid and you closed them at the same time, you'd succeed in syncing Texas with the rest of the nation.

;-)

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Paul Hovnanian	paul@hovnanian.com 
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Have gnu, will travel.

^^^ Make that sw3 (no coffee yet).

C is obviously for KVAR supply.

--
Paul Hovnanian	paul@hovnanian.com
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Have gnu, will travel.

What it did was puzzle the hell out of me, because all I could think of was what John Larkin suggested, only it sounded too screwy.

Is this board-level, or are you tossing macrocells into an ASIC? Unless you're trying to out-Jeorg Jeorg, it seems like you'd get _much_ better performance with an op-amp instead of the 'HCU04 part. (Of course, if it's AC coupled then I suppose that the bias doesn't matter squat. Hmm).

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Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

It's on an ASIC. It's a comparator, comparing V1 (analog) against V2 (10-bit DAC output) in a SAR sequence.

(I posted the switch sequence in a previous post.)

I won't try to out-Joerg Joerg... he does things that he claims are required by medical electronic rules... things I find unsanitary and unsafe ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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I don't see the post with the sequence, but I see how it could work: close SW1 & SW2 & give the "gate" time to settle -- now the input is smack in the middle of the "gate's" input range. Then open SW1 & SW2 -- the 'HCU04 then goes high or low due to it's way-high gain (or stays in the middle, just to confound you -- I hope you have that accounted for).

Should also work to close SW3 & SW2, alternately with SW1, same idea, just different sense out of the "gate".

Nifty.

I assume this is something that doesn't give you an "analog amplifier" block, hence the '04?

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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

That's called the 1 LSB "dither" ;-)

Actually I follow that stage with two more like-sized stages, the clock into the digital, so there's no "float".

'HCU04 is stable under feedback (since it's a single stage). 'HC04 is three stages... sings like a banshee ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Without looking at any of the other answers:

You close SW3 and SW2 for a while and C ends up with the difference between V1 and the 0/1 boundary of the HCU04. You then open SW3 and SW2 and close SW1 to compare V2 with what V1 was a little while ago.

Yep.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

How on earth does all that - not to mention the timing control for the switches - take fewer transistors than a comparator?

If it's because there is no comparator block, then it seems odd that it has analog switch blocks, and enough versatility to make an R2R ladder, and to place a cap in series. All those analog building blocks but no comparator?

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Rail-to-rail equivalent?

Try it sometime ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Isn't it nice how Google groups turns any two spaces in a row into space, =, A, 0?

Idiots.

moosefet posted a double space and it wasn't mangled.

it seems to only be doing it to quoted material. (still not a good thing)

perhaps you should ge a mime-capable newsreader :)

=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 |

You have to set the font correctly. Google must not only be using a fixed font, it also has to be one that your really have installed.

It doesn't if the Google Groupers pull their heads out of their asses. The proper technique for using Google Groups has been described here several times:

snipped-for-privacy@y22g2000prd.googlegroups.com

*-link+*-Reply-at-the-bottom-*-*-*+DO-NOT+More.Options+blockquoting+other.people's.sigs+weird-looking.postsnews: snipped-for-privacy@c19g2000prf.googlegroups.com

Well you didn't say it had to work rail-to-rail. :)

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