Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

I tried to use a high-power, ultra-fast OpAmp to make a simple adder.
The problem I got so far is that the rising time is killed when I
connect the piezo (C=600nF). I need a rising time of less than 10us for
Vpp=20V.
The other problem with this design is that the 2 drivers output are not
isolated from each other.

Does anyone has an idea on how I can solve my problem.
Does anyone know good reference (book, web site...) to build piezo
drivers.

Thank you very much for your help.

Why would you or anyone need a d.c. piezo driver? I'm obviously
missing something here.

Harry C.


wrote:
Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

I tried to use a high-power, ultra-fast OpAmp to make a simple adder.
The problem I got so far is that the rising time is killed when I
connect the piezo (C=600nF). I need a rising time of less than 10us for
Vpp=20V.
The other problem with this design is that the 2 drivers output are not
isolated from each other.

Does anyone has an idea on how I can solve my problem.
Does anyone know good reference (book, web site...) to build piezo
drivers.

Thank you very much for your help.

On 2006-06-26, wrote:
Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).

these figures represent what?

I want to build something that can add those two signals.

connect the devices in series?

use a resistor network?

I tried to use a high-power, ultra-fast OpAmp to make a simple adder.
The problem I got so far is that the rising time is killed when I
connect the piezo (C=600nF). I need a rising time of less than 10us for
Vpp=20V.
The other problem with this design is that the 2 drivers output are not
isolated from each other.

tell us what else you need first.

Does anyone has an idea on how I can solve my problem.

no idea what your problem is.

Does anyone know good reference (book, web site...) to build piezo
drivers.

seems like a push-pull outyput stage is all that's needed...

Bye.
Jasen

I need a DC piezo driver because I use the piezo as a linear motor in
the nano-micrometer range.
So by changing the DC voltage I change the piezo length.
This is very common in (nano) physics research lab.

wrote:
Why would you or anyone need a d.c. piezo driver? I'm obviously
missing something here.

Harry C.

Thanks, that makes sense. I've seen similar things done in Mossbauer
effect type work.

Harry C.


wrote:
I need a DC piezo driver because I use the piezo as a linear motor in
the nano-micrometer range.
So by changing the DC voltage I change the piezo length.
This is very common in (nano) physics research lab.

wrote:
Why would you or anyone need a d.c. piezo driver? I'm obviously
missing something here.

Harry C.

On 26 Jun 2006 12:23:27 -0700, wrote:

Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

---
Please bottom post.

you say you bought an AC piezo driver, but you claim that it goes
from zero to 20 volts, which makes it a DC piezo driver which can
swing between zero and 20 volts.

Then you say that you have a DC piezo driver which can swing from
zero to 150 volts, and that you want to add the outputs of both
drivers.

From that I gather that you'd like to be able to, say, crank the
150V driver up to 150V and let the 20V driver ride on that, so the
piezo would be seeing a signal varying from 150V to 170V at a 100kHz
rate.

Is that what you want?


--
John Fields
Professional Circuit Designer

Yes, correct.


John Fields wrote:
On 26 Jun 2006 12:23:27 -0700, wrote:

Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

---
Please bottom post.

you say you bought an AC piezo driver, but you claim that it goes
from zero to 20 volts, which makes it a DC piezo driver which can
swing between zero and 20 volts.

Then you say that you have a DC piezo driver which can swing from
zero to 150 volts, and that you want to add the outputs of both
drivers.

From that I gather that you'd like to be able to, say, crank the
150V driver up to 150V and let the 20V driver ride on that, so the
piezo would be seeing a signal varying from 150V to 170V at a 100kHz
rate.

Is that what you want?


--
John Fields
Professional Circuit Designer

On 28 Jun 2006 12:22:37 -0700, wrote:

Yes, correct.

---
Then why, after I politely asked you to bottom post, as is the
custom in these groups, did you so rudely top post?

You want free help but you want it on your own terms?

Maybe someone else will help you, but I won't.

--
John Fields
Professional Circuit Designer


John Fields wrote:
On 26 Jun 2006 12:23:27 -0700, wrote:

Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

---
Please bottom post.

you say you bought an AC piezo driver, but you claim that it goes
from zero to 20 volts, which makes it a DC piezo driver which can
swing between zero and 20 volts.

Then you say that you have a DC piezo driver which can swing from
zero to 150 volts, and that you want to add the outputs of both
drivers.

From that I gather that you'd like to be able to, say, crank the
150V driver up to 150V and let the 20V driver ride on that, so the
piezo would be seeing a signal varying from 150V to 170V at a 100kHz
rate.

Is that what you want?


--
John Fields
Professional Circuit Designer

wrote:
Yes, correct.


John Fields wrote:
On 26 Jun 2006 12:23:27 -0700, wrote:

Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

---
Please bottom post.

you say you bought an AC piezo driver, but you claim that it goes
from zero to 20 volts, which makes it a DC piezo driver which can
swing between zero and 20 volts.

Then you say that you have a DC piezo driver which can swing from
zero to 150 volts, and that you want to add the outputs of both
drivers.

From that I gather that you'd like to be able to, say, crank the
150V driver up to 150V and let the 20V driver ride on that, so the
piezo would be seeing a signal varying from 150V to 170V at a 100kHz
rate.

Is that what you want?


--
John Fields
Professional Circuit Designer

A simple capacitor/diode clamp circuit would seem to do

On 2006-06-27, wrote:
I need a DC piezo driver because I use the piezo as a linear motor in
the nano-micrometer range.
So by changing the DC voltage I change the piezo length.
This is very common in (nano) physics research lab.

if both sources are ground referenced hook the DC source to one
terminal and the AC source to the other end

Bye.
Jasen

So whats up with the request to bottom post ..

what is convenient for some is a pain for others

when you have people that insist on posting the whole
post of the previous poster, its a pain to have to
scroll thru the history to get to a one line answer.

bottom posting never did make sense







wrote in 1151549381.945040.139300
@i40g2000cwc.googlegroups.com:


wrote:
Yes, correct.


John Fields wrote:
On 26 Jun 2006 12:23:27 -0700, wrote:

Hi,
I bought an AC piezo driver (0-20V, bandwidth100kHz).
I also have a DC piezo driver (0-150V).
I want to build something that can add those two signals.

---
Please bottom post.

you say you bought an AC piezo driver, but you claim that it goes
from zero to 20 volts, which makes it a DC piezo driver which can
swing between zero and 20 volts.

Then you say that you have a DC piezo driver which can swing from
zero to 150 volts, and that you want to add the outputs of both
drivers.

From that I gather that you'd like to be able to, say, crank the
150V driver up to 150V and let the 20V driver ride on that, so the
piezo would be seeing a signal varying from 150V to 170V at a 100kHz
rate.

Is that what you want?


--
John Fields
Professional Circuit Designer

A simple capacitor/diode clamp circuit would seem to do

On Thu, 29 Jun 2006 17:34:19 GMT,
(Mike_in_SD) wrote:


So whats up with the request to bottom post ..

what is convenient for some is a pain for others

when you have people that insist on posting the whole
post of the previous poster, its a pain to have to
scroll thru the history to get to a one line answer.

bottom posting never did make sense

---
When you're inconsiderate of others who may come to the thread some
time after it started, then it may not seem to make much sense, even
though it does. You don't read a book backwards, and it's
inconsiderate to force others to read a series of articles
chronologically backwards.


Even Google thinks so.

From:

http://groups.google.com/support/bin...2348&topic=250


"Summarize what you're following up.

When you click "Reply" under "show options" to follow up an existing
article, Google Groups includes the full article in quotes, with the
cursor at the top of the article. Tempting though it is to just
start
typing your message, please STOP and do two things first.
Look at the quoted text and remove parts that are irrelevant.
Then, go to the BOTTOM of the article and start typing there.
Doing this makes it much easier for your readers to get through your
post. They'll have a reminder of the relevant text before your
comment, but won't have to re-read the entire article.
And if your reply appears on a site before the original article
does,
they'll get the gist of what you're talking about."


---
BTW, speaking of being considerate, you need to clean up your
punctuation as well as learn to top-post as the Romans do.


--
John Fields
Professional Circuit Designer

["Followup-To:" header set to sci.electronics.misc.]
On 2006-06-29, Mike_in_SD wrote:

So whats up with the request to bottom post ..

it puts stuff in chronological (or conversation) order.

when you have people that insist on posting the whole
post of the previous poster, its a pain to have to
scroll thru the history to get to a one line answer.

That's what the page-down key is for.


having to scroll to the bottom of the post to see what your talikng
about and then back up to the message is worse.

Bye.
Jasen