Does this IC exist?

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?

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.

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.

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.

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


Rob

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.

This is nearly perfect!! Thanks John!! XD

Graynomad: 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.

There is nothing “semi high voltage” about 480V, its lethal. I’d worry about getting the isolation right first before anything else.

480V

Warning Will Robinson, new and lethal criteria discovered :slight_smile:

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

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

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.

Graynomad:

480V

Warning Will Robinson, new and lethal criteria discovered :)

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.