3.7v Battery Charger using IRFZ44N Mosfet with Shunt regulator works in real life, but Multisim Stimulation not working

Thread Starter

stevedee

Joined Nov 5, 2023
3
Good evening everyone, I'm new here and I wish to get help for the little challenges I'm having with multisim

I watched this circuit online and it works perfectly well, I'm trying to replicate the circuit for a project but I want to stimulate it first. Having connected it properly as shown, the circuit fails to do anything. No error code and none of the LEDs are working. The circuit is meant to stimulate low battery (red LED) and full battery(Green LED) in a 18650 3.7v Lithium-ion battery.

I've tried different circuits that work perfectly online but none is stimulating. What am I doing wrong, please?

Note: The stimulation software is multisim

Attached below is the multisim image and the circuit image itself.

Thanks
 

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crutschow

Joined Mar 14, 2008
34,047
Sorry, but I don't see how that circuit can work.
It has no feedback from the voltage across the battery to control the charging current.
The TL431 feedback just goes to the +5V supply voltage, so is unaffected by the battery voltage.

If the online circuit works, it's not the one you posted.
 
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Thread Starter

stevedee

Joined Nov 5, 2023
3
Sorry, but I don't see how that circuit can work.
It has no feedback from the voltage across the battery to control the charging current.
The TL431 feedback just goes to the +5V supply voltage, so is unaffected by the battery voltage.

If the online circuit works, it's not the one you posted
What modification can I make to make it works properly

Thanks
 

Sensacell

Joined Jun 19, 2012
3,400
It's a bad circuit- from the messy land of the internet.

I would discard it and start over- unless you like exploding batteries?
 

Sensacell

Joined Jun 19, 2012
3,400
I would look at the many chipsets that are made for purpose.
You have not explicitly mentioned the battery chemistry, you must be very careful to charge the battery properly- for the specific type.

Google "battery charger IC for LiFePO4"
 
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