Instantaneous charge state of supercapacitor detection

[Adeyemi1071]

Hello friends,

Is there any superlow powered components or technique i can use to detect instantaneous charge state of energy reservoir (supercepacitor) and send feedback to microcontroller without adc's (to save power)? I have previously used a low powered comparator but it only measures either higher or lower than a threshold. I need to compare multiple threshold levels.

Thanks

Sincerely,

 

[Nanren888]

Is that instantaneous change or instantaneous detection?
Not clear whether you have the references, are they voltage?, or want the references too.
How many thesholds?
Multiple comparators?
.
Transistors can be used configured so that they basically only conduct when the input is above a threshold.
mosfets draw little power when off.
.
Perhaps you could give us more of an idea what you are after.

 

[Adeyemi1071]

Thanks for the reply. The thing is, we have a power supply that charges a supercapacitor and supplies a system. We want to make the system energy aware such that it checks the latest state of charge (Ah) in the reservoir or supercapacitor after each cycle of operation and when it is below a certain threshold, we change the microcontroller operating mode to a lesser current consuming operation. We have previously used a low powered comparator that sleeps the mcu when voltage goes below a certain threshold and wakes it when it goes above a certain threshold. But now we have multiple operation levels (about three thresholds) not just sleep and wake

 

[crutschow]

Can't you just use three comparators?

 

[Alec_t]

How about this (assuming the threshold levels aren't too critical)?