100V DC/DC Converter

[Mike Blankenship]

I am looking for a DC/DC converter to boost the Voltage to 100V from a
5 or 9 Volt input. I have found the following circuit which will do this :

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1751/ln/en

But I am looking for a device in a DIP package. National has a couple of
parts
which will boost to 80Volts.

mike

 

[cornytheclown]

"Mike Blankenship" <michael_blankenship@maximhq.com> wrote in message news:<MRhZb.27939$PP4.5739@newssvr25.news.prodigy.com>...

I am looking for a DC/DC converter to boost the Voltage to 100V from a
5 or 9 Volt input. I have found the following circuit which will do this :

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1751/ln/en

But I am looking for a device in a DIP package. National has a couple of
parts
which will boost to 80Volts.

mike

No idea myself........but I am curious as to what type of application
you are using this for.......if you dont mind...

 

[Mike Blankenship]

Im building a MegOhm meter and need to test at 100V

"cornytheclown" <cornytheclown@hotmail.com> wrote in message
news:8e8f59d4.0402201946.18cc027d@posting.google.com...

"Mike Blankenship" <michael_blankenship@maximhq.com> wrote in message
news:<MRhZb.27939$PP4.5739@newssvr25.news.prodigy.com>...
I am looking for a DC/DC converter to boost the Voltage to 100V from a
5 or 9 Volt input. I have found the following circuit which will do this
:

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1751/ln/en

But I am looking for a device in a DIP package. National has a couple of
parts
which will boost to 80Volts.

mike

No idea myself........but I am curious as to what type of application
you are using this for.......if you dont mind...

 

[DarkMatter]

On Fri, 20 Feb 2004 06:32:13 GMT, "Mike Blankenship"
<michael_blankenship@maximhq.com> Gave us:

I am looking for a DC/DC converter to boost the Voltage to 100V from a
5 or 9 Volt input. I have found the following circuit which will do this :

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1751/ln/en

But I am looking for a device in a DIP package. National has a couple of
parts
which will boost to 80Volts.

mike

You also need to declare the power requisites which you intend to
feed. There are several types of converter for that voltage range,
and they do not all perform the same in all load conditions.. of
course... so, we need more info.

 

[DarkMatter]

On Sat, 21 Feb 2004 04:15:45 GMT, "Mike Blankenship"
<michael_blankenship@maximhq.com> Gave us:

Im building a MegOhm meter and need to test at 100V

Your best bet would be to make a small converter with variable

output voltage. That way, you could always have the ability to
calibrate the output voltage, instead of blindly relying on it to
remain steady over time and temperature.

Use a PWM, a couple of FETs, and make chopped output, or use a self
resonant oscillator, pump a transformer, and rectify the output. Put
a take off, and control loop in it, and you can adjust the voltage.
If you are building the entire circuit, it isn't that hard to simply
build a MVPS onto the system as well.

Hell, a true RMS meter, a known low drift precise value bottom
resistor, and the resistor under test are all you need. And the
excitation voltage, of course. At that point, you could use AC to
pump it from a variac, and use current to figure it, or voltage.

Another thought is to use those old B+ batteries the old handheld
radios and fluorescent lights used. They were like 67 volts. Two of
those series together...

Hehehe...

 

[Mike Blankenship]

My application only requires .700 amps. Since im using a voltage divder to
test up to 1 Teraohm. I will need very little current from the supply
wohoo I just received my test resistors today. 10G 100G 1T and 10Terahom .

Dealing with the very low current wont be a problem, Im using a LMC6001 with
a 25fa input bias current.
This is a handheld device so board space is an issue. National Parts will
only go to 80V with a simple
single IC and 1 inductor solution. So Im still looking.

"DarkMatter" <DarkMatter@thebarattheendoftheuniverse.org> wrote in message
news:impd309hp4ihc7h0ucophqifka60eo7ksq@4ax.com...

On Sat, 21 Feb 2004 04:15:45 GMT, "Mike Blankenship"
michael_blankenship@maximhq.com> Gave us:

Im building a MegOhm meter and need to test at 100V

Your best bet would be to make a small converter with variable
output voltage. That way, you could always have the ability to
calibrate the output voltage, instead of blindly relying on it to
remain steady over time and temperature.

Use a PWM, a couple of FETs, and make chopped output, or use a self
resonant oscillator, pump a transformer, and rectify the output. Put
a take off, and control loop in it, and you can adjust the voltage.
If you are building the entire circuit, it isn't that hard to simply
build a MVPS onto the system as well.

Hell, a true RMS meter, a known low drift precise value bottom
resistor, and the resistor under test are all you need. And the
excitation voltage, of course. At that point, you could use AC to
pump it from a variac, and use current to figure it, or voltage.

Another thought is to use those old B+ batteries the old handheld
radios and fluorescent lights used. They were like 67 volts. Two of
those series together...

Hehehe...

 

[Mike Blankenship]

My application only requires .700 amps. Since im using a voltage divder to
test up to 1 Teraohm. I will need very little current from the supply
wohoo I just received my test resistors today. 10G 100G 1T and 10Terahom .

Dealing with the very low current wont be a problem, Im using a LMC6001 with
a 25fa input bias current.
This is a handheld device so board space is an issue. National Parts will
only go to 80V with a simple
single IC and 1 inductor solution. So Im still looking.

"Mike Blankenship" <michael_blankenship@maximhq.com> wrote in message
news:MRhZb.27939$PP4.5739@newssvr25.news.prodigy.com...

I am looking for a DC/DC converter to boost the Voltage to 100V from a
5 or 9 Volt input. I have found the following circuit which will do this :

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1751/ln/en

But I am looking for a device in a DIP package. National has a couple of
parts
which will boost to 80Volts.

mike

 

[DarkMatter]

On Sat, 21 Feb 2004 06:29:31 GMT, "Mike Blankenship"
<michael_blankenship@maximhq.com> Gave us:

My application only requires .700 amps. Since im using a voltage divder to
test up to 1 Teraohm. I will need very little current from the supply
wohoo I just received my test resistors today. 10G 100G 1T and 10Terahom .

The ten Mohm will pass the most current, as you are aware.

Perhaps a ranging switch, and several "bottom resistors" are needed
to keep the test current relatively even in each range.

Dealing with the very low current wont be a problem, Im using a LMC6001 with
a 25fa input bias current.

Cool device.

This is a handheld device so board space is an issue. National Parts will
only go to 80V with a simple
single IC and 1 inductor solution. So Im still looking.

Resistors of that high a value may test at one value with a mere
hundred volts, but at true HV levels, even mere breath or a
fingerprint is enough to make them leak badly.

Be sure to use gloves whenever handling any high value resistors,
especially if their intended application is that of a feed back for an
HV output. The dipped, glazed versions are less susceptible, but
would still leak across their surfaces under high potentials. The
non-coated raw ceramic substrate versions are VERY susceptible, and
even absorb water and other media (hygroscopic).

A good brominated solvent (EnSolv), or hot 99% IPA is a good thing
to wash them with, just before the testing, and certainly before any
potting steps..