Hi,
The application note has a series of different circuits using op amps and the REF200, this link shows a set-up where the trimpot could be replaced with the control voltage input:
https://www.merghart.com/p/28/opamp-adjustable-current-source
It's just one example, there are loads of current source/sink circuits and application notes available by individuals and semiconductor manufacturers, many in pdf format.
You could look for op amp circuit collection app notes, they have lots of ideas, some which can be slightly modified easily to fit your needs.
Also, the LM134 or LM334 current reference IC, and voltage references like the 4041 or TL43 may have a wide range of "typical application" schematics in the datasheets that are simple to implement.
I like browsing op amp and voltage current ref, etc., app notes for things such as you wish to implement, or that "Current Sources and Voltage References" book, "print version" should bring it up in a search, as they are brimming with reliable, tested cicuits, it saves time inventing things that don't work or accidentally copying amateurish circuits from "dodgy" websites.
e.g. AN-31, snoa621c, A collection of Amp Applications
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a window to compare with a periodic ramp
Hi, "FIGURE 37. Window comparator with voltage programmable window center, and resistor programmable window width". in the previously uploaded pdf, sounds like it could fit the bill, but need to change dual supply to single supply. I'm sure some-one would be glad help with that if you try and have difficulties getting it to function correctly.
Three more voltage controlled current sources using op amps, the first two are single supply, the third is dual supply so may or may not be adaptable to single supply operation.
https://www.daycounter.com/Circuits/Current-Servo/Current-Servo.phtml
https://www.tina.com/blog/voltage-controlled-current-source-circuit/
**broken link removed**
(for the third you need to click on "figure" to see the schematic in a new browser tab)
I think the "Implementations and applications...", figure 37 sounds closest to what you want to do, and looks easy to adapt via passive components, but is dual supply. In principle, I don't see that being so hard to adapt to single supply operation, window comparators are quite easy to make and adapt.
There are lots of free schematic capture (design) programs, some including simulation, it's worth spending an hour learning to use them to sometimes show others what you mean, by exporting a jpg. or pdf or whatever document format of the schematic. Problems only arise when you need to simulate a specific part that is not available in a program. LTSpice is schematic capture and simulation. TINA-TI is also both. DesignSpark is schematic capture and PCB design, and very easy to use after a short while, but most are, design is "easy", simulation not so much at all. There are many other free programs, there's a section here where they are discussed, could be helpful if you're interested.