Go Down

Topic: Does this IC exist? (Read 2107 times) previous topic - next topic

QuagmireMan

I have been looking for and IC that can take an oscillating signal (600Hz minimum) and amplify it.  Sounds easy right?  Well there is a little catch… I would like to have the amplification factor adjustable via a digital signal.  For example this amplifier is sent a digital signal to increase the signal multiplication factor by 1.5 each time it is pulsed. Then it can be stepped back down.  I could do this with a little more complicated setup (DAC and signal multiplier) but I was hoping something already existed on a chip that could do it in one package.  I need to have 36 individual controlled signal amplifiers.

Any insight or other recommendations?

cmiyc

ICs are created and sold for use in applications.  Explain the application you are trying to solve instead of the parts.  That will help you find if the IC exists and help others suggest what you need.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

johnwasser

Look for "Programmable Gain" amplifiers.  The Microchip MCP6S21 (8-pin DIP) has an SPI interface and gain settings of 1,2,4,5,8,10,16, and 32.  They also have units with 2, 6 and 8 inputs but they are multiplexed so there is only one output.
Send Bitcoin tips to: 1G2qoGwMRXx8az71DVP1E81jShxtbSh5Hp

MarkT

Also a "multiplying DAC" is a DAC that scales its output by a analog control voltage.  Not sure they cope with an AC control voltage though.

There may also be digital programmable attenuators.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

graynomad

Another option, opamp with a digital pot in the feedback.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

QuagmireMan


Look for "Programmable Gain" amplifiers.  The Microchip MCP6S21 (8-pin DIP) has an SPI interface and gain settings of 1,2,4,5,8,10,16, and 32.  They also have units with 2, 6 and 8 inputs but they are multiplexed so there is only one output.


This is nearly perfect!! Thanks John!!  XD


QuagmireMan


Another option, opamp with a digital pot in the feedback.

_____
Rob


I was thinking about that as well, but I wanted to setup a schedule to change the gain during different times of the day. Plus the circuit will be will semi "high" voltage (480V) so I would like to isolate everything from the user as well.

MarkT

There is nothing "semi high voltage" about 480V, its lethal.  I'd worry about getting the isolation right first before anything else.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

graynomad

Quote
480V

Warning Will Robinson, new and lethal criteria discovered :)

Quote
but I wanted to setup a schedule to change the gain during different times of the day.

I don't see how that precludes using the digital pot.

I think you have to explain the minor detail of 480V before anyone can make further comment.

For a start is this a small signal with a 480V offset, or a full 480V swing.

_____
Rob
Rob Gray aka the GRAYnomad www.robgray.com

winner10920

Id guess the signal isnt 480 right? Just whatever you are controlling I assume
just curious what is the main project? It sounds quite interesting,  in an industrial kinda way lol

Grumpy_Mike

Quote
I have been looking for and IC that can take an oscillating signal (600Hz minimum) and amplify it.

You normally talk about the maximum frequency of an amplifier, the minimum one will be zero or DC.

This is one of those threads that ask about how to tie a shoe lace and only later do you find out that the shoe lace is located on the moon.

QuagmireMan

#11
Dec 07, 2011, 07:23 pm Last Edit: Dec 07, 2011, 07:32 pm by QuagmireMan Reason: 1

Quote
480V

Warning Will Robinson, new and lethal criteria discovered :)

Quote
but I wanted to setup a schedule to change the gain during different times of the day.

I don't see how that precludes using the digital pot.

I think you have to explain the minor detail of 480V before anyone can make further comment.

For a start is this a small signal with a 480V offset, or a full 480V swing.

____
Rob



I am not directly interfacing with the 480V, there is a PT (Potential transformer) and CT (Current transformer) that I will be interfacing with.  If there is some internal short inside the equipment it has the potential of placing 480V on my wiring going to my IC and Arduino.  Just trying to stay safe.

I have worked with systems upwards of 765KV so in my field this is considered low voltage lol.

I still have to find the range of my CT and PT, more than likely it will be less than 5V AC.


Go Up