What is the importance of magnitude comparator?

Answer 1

Generally, magnitude comparators are digital circuits (IC's) which have two ports which accept, and latch two 8 or 16 bit binary numbers and have three single bit outputs: "Greater than, less than, and equal."

I have used these personally in several digital control systems.

I guess the "importance" is twofold. First, as you can use a single IC you simplify the hardware, but more importantly, for certain operations, they can be invaluable.

One simple use would be comparing the output of a free running digital counter to some fixed number. This fixed number, if derived from user adjustable binary hex switches, would allow control based on some adjustable terminal count. For instance, if the counter also fed into a D to A converter, and use the magnitude comparator to compare the two numbers, you now have a user adjustable ramp which can further be used with analog comparators to trigger many sorts of analog systems and also acts as a digital divider. One could create a temperature control for example using a sensor as one input but calculated in the digital domain, possibly with some microcomputer to make decisions.

I once used a very similar setup using two daisy-chained magnitude comparators in a telemetry system where the comparators monitored a counter which counted digital telemetry pulses and thus was the "memory of the number of plses and were used as a trigger for a setpoint alarm or maximum allowable user adjusted limit. As mentioned above, they can aslo be used to make a digital divider. For instance, using a free-running counter as one comparator input, and user switches as the other, you will get an "Equal to" signal for every x counts / y user input count. Very simple way to divide counts by any amount.

It's not so much "what's the importance" as that fully depends on the application, but rather the versatility and all the clever things one can use them for. I've designed more complex uses for them but my lack of recall of the details would not add to this answer but I did do some pretty cool, very specialized things which would have been difficult dto do without using the magnitude comparators. Only your imagination limits the cool things you can uyse them for.

Basically, Analog circuits like op-amps compare strictly in the analog domain. Magnitude comparators allow comparing purly in the digital domain. Combining the digital, D-to-A converters, and op-amps allows doing both simultaneously, if needed by the aplication.

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