Author Topic: Li-ion protection modifying  (Read 135 times)

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Offline bodzio_stawski

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Li-ion protection modifying
« on: Yesterday at 06:10:47 pm »
Hello!

I have a li-ion protection IC - AP9101CK6-AXTRG1 to connect with n-type MOSFETS. And this one has the overdischarge
detection voltage at 2.8 V.

https://www.tme.eu/Document/2363835cc5634a92b6e94bc773e39f4b/AP9101C.pdf



Typical aplication looks very similar to the other protection ICs (like DW-01).



But I wonder if there is a possibility to modify/adapt such a schematic to increase the voltage limit (eg to 3.3V). Is it possible in such circuits?
 

Offline jbb

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Re: Li-ion protection modifying
« Reply #1 on: Yesterday at 07:23:07 pm »
You could perhaps try a voltage divider, BUT that would change the over voltage threshold too. I don’t recommend it.

Safest solution is to source a different version of the chip with higher setting built in.

Practical solution is to apply some under voltage sensing in your circuitry to go to sleep when the voltage gets low.
 

Offline bodzio_stawski

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Re: Li-ion protection modifying
« Reply #2 on: Yesterday at 08:22:33 pm »
Yes, right:), for a moment I considered a voltage divider or a diode between R1 and Vdd, but that's a rather bad idea:(

Another chip with higher voltage setting will be my dream, but 3V is the maximum which I see for some ICs :c

Quote
Practical solution is to apply some under voltage sensing in your circuitry to go to sleep when the voltage gets low.

Could you write an example?:)

 

Offline jbb

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Re: Li-ion protection modifying
« Reply #3 on: Yesterday at 10:54:50 pm »
Well, maybe you could use a soft power switch circuit, and put a voltage supervisor chip down to turn it off if voltage goes low.

If using a microcontroller, you could use low power sleep modes.

Some have a Brown Out Detector to reset the chip. On boot up, you can look for a BOR status bit; if set, you know something went wrong and can go to deepest sleep mode.

Alternatively you could use an ADC to sense the battery voltage every once in a while and go to deepest sleep if it’s too low. (But make sure the battery voltage measurement circuit doesn’t waste too much current...)
 


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