Need an Op amp which can take a 60V - 140 V input

illum · 23rd March 2005, 08:26 AM

Hi
I really need help on this thing. i need and opamp that will not burn or get spoiled by giving it a high voltage input. like 60 to 140 v input.

plz reply asap my project is stuck on this part.

pinkmouse · 23rd March 2005, 09:39 AM

Why does it need to be so high?

bocka · 23rd March 2005, 09:54 AM

The OPA445 has a power suplly range from +/- 10V to +/-45 V. Maybe that part fits in your project. Sometimes it's better to use a voltage divider on the input or an difference amplifier like the INA117. Both devices are from TI.

paulb · 23rd March 2005, 11:06 AM

This company has them. They're expensive.
http://eportal.apexmicrotech.com/mainsite/index.asp

peranders · 23rd March 2005, 11:16 AM

60-140 V in but what about out? The same as a LM3886 can deliver or more?

What about a voltage divider at the input? Is this enough?

Can you please describe more what your goal is? I think it's pretty easy to solve.

One solution is this

illum · 23rd March 2005, 01:03 PM

basically i need something that will amplify a signal less then 15V and reduce the voltage of signal with voltage more then 40V

macboy · 23rd March 2005, 01:08 PM

Quote:

Hi
I really need help on this thing. i need and opamp that will not burn or get spoiled by giving it a high voltage input. like 60 to 140 v input.

Everyone seems to be assuming that you mean 60 to 140 V power supply. But you said input. So I will assume that you really meant input.

What you need to do is use a voltage divider before the input of the opamp. A 10:1 divider will reduce the voltage to 6 to 14 V which is within the range of most opamps. Your power supply should be a few more volts than the maximum input voltage. Of course, your output voltage will also be limited by the power supply voltage, but since you didn't mention a specific required voltage, we can only assume that you don't need anything special.

jacco vermeulen · 23rd March 2005, 01:19 PM

Quote:

Originally posted by peranders
One solution is this

Dear PerAnders,

Me thinks Mark Alexander's IGBT amplifier is not a pretty easy solution.

peranders · 23rd March 2005, 01:25 PM

Quote:

Originally posted by illum
basically i need something that will amplify a signal less then 15V and reduce the voltage of signal with voltage more then 40V

What kind of input is it and what is the load (output), how much power?

illum · 23rd March 2005, 01:34 PM

it basically is a telephone signal. when simple voice is transmitted the voltage is low but when a ring signal is suppose to be passed the voltage is between 40 - 160. so i need to reduce this voltage with out disrupting the normal voice signals.

23rd March 2005, 08:26 AM	#1
illum diyAudio Member Join Date: Mar 2005 Location: peshawar	Need an Op amp which can take a 60V - 140 V input Hi I really need help on this thing. i need and opamp that will not burn or get spoiled by giving it a high voltage input. like 60 to 140 v input. plz reply asap my project is stuck on this part.

23rd March 2005, 09:39 AM	#2
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Why does it need to be so high? __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

23rd March 2005, 11:16 AM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	60-140 V in but what about out? The same as a LM3886 can deliver or more? What about a voltage divider at the input? Is this enough? Can you please describe more what your goal is? I think it's pretty easy to solve. One solution is this __________________ /Per-Anders (my first name) or P-A as my friends call me

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23rd March 2005, 09:54 AM	#3
bocka diyAudio Member Join Date: Jul 2003 Location: Hannover	The OPA445 has a power suplly range from +/- 10V to +/-45 V. Maybe that part fits in your project. Sometimes it's better to use a voltage divider on the input or an difference amplifier like the INA117. Both devices are from TI.

23rd March 2005, 11:06 AM	#4
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	This company has them. They're expensive. http://eportal.apexmicrotech.com/mainsite/index.asp

23rd March 2005, 01:03 PM	#6
illum diyAudio Member Join Date: Mar 2005 Location: peshawar	basically i need something that will amplify a signal less then 15V and reduce the voltage of signal with voltage more then 40V

23rd March 2005, 01:34 PM	#10
illum diyAudio Member Join Date: Mar 2005 Location: peshawar	it basically is a telephone signal. when simple voice is transmitted the voltage is low but when a ring signal is suppose to be passed the voltage is between 40 - 160. so i need to reduce this voltage with out disrupting the normal voice signals.

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