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recently I asked the forum for help to build a 12v li-ion battery undervoltage protection circuit and some kind members solved the issue (click to preview). however, (user @Prathik Prashanth) mentioned a very clever point that you don't usually take into account when simulating a circuit:

When you are building an undervoltage lockout circuit, you need to give it some hysteresis. When the undervoltage protection kicks in, the battery gets disconnected and stops supplying power to the boost converter. This causes the battery voltage to rise slightly and the undervoltage circuit will no longer detect an udervoltage and it reconnects the battery again which causes its voltage to drop and the circuit to cut off power. The circuit will cycle like this. Adding some hysteresis will prevent this

how can I achieve hysteresis in my circuit? enter image description here

jzeds1491
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    You probably want a schmitt trigger. This is a common circuit configuration that is easily found. – Kartman Jul 20 '21 at 13:29
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    Thanks! I've searched for Schmitt trigger and got some idea about what it is, now do I need to reconfigure the whole circuit? – jzeds1491 Jul 20 '21 at 14:10
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    @kartman my input voltage is supplied by a battery pack and as voltage level decreases this changes reference voltage setting for opamp ic ( resistor values changes from 12v to 10.5v input) – jzeds1491 Jul 20 '21 at 16:35
  • I don't know if a Schmitt trigger is going to have enough hysteresis. How many volts does the battery bounce? I would use a microcontroller. But I think a decent design book on op-amps should have an example of how to design hysteresis with op-amps. – MicroservicesOnDDD Jul 21 '21 at 05:18

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