BQ40Z80: PTC instead of NTC

Hello Giorgio, 

You cannot use a PTC instead of an NTC, because the pin configuration on the gauge is completely different. 

Regards, 

Jonny. 

Hi Jonny,

and regarding the usage of TL103WB as CC-CV controller (AN SILA619)? My doubt is the current absorbed  by the amplifiers (1mA) that for my opinion is too much.

Hello, 

I am looping in the Op Amp team to help with this question. 

Regards, 

Jonny. 

Hey Giorgio,

What current is your SMPS able to provide? If it is greater than 1mA, then the CC feedback loop will properly be able to feed back the current sent to the battery, and the CC/CV feedback loop will work as intended. If your SMPS is unable to provide 1mA, it will not properly turn on the amplifier, and you will not get the appropriate feedback. Consequently, if your SMPS cannot supply more than 1mA, I'm afraid you will not be charging your batteries very quickly.

Best,
Jerry

Of course my SMPS is able to provide to a battery pack more than 1.5Amps, but my preoccupation is during a standby (NO MAIN SUPPLY and SMPS obviousy OFF) because TL103WB absorb 1mA from li-Ion battery pack and it as not a standby mode.

Hey Giorgio,

Ah okay, are you worried about excessively draining the battery when it is not charging? Is the battery disconnected from the CC/CV circuit when the SMPS is in standby? In the below reference design, the battery is meant to be disconnected when not being charged. This would be similar to a cordless tool battery charger.

Will the CC/CV loop be placed on the battery side so that it is constantly biased by the battery? You may be able to implement a discrete shutoff system to the supply of the CC/CV loop to turn this off when the battery is disconnected from the charger, similar in concept to the battery undervoltage protection circuit that does not allow the feedback loop to be turned on when the battery voltage is below a certain threshold.

Please let me know if my questions are not relevant, I am just trying to get an understanding of the system.

Best,
Jerry

Thank you Jerry,

can you send me an image with greater resolution or a link?

Have a good day

Hey Giorgio,

Of course! In SLLA619 this project is actually linked in the first paragraph, PMP23224. Here is the link, and from this page you can download the full schematic of this project

https://www.ti.com/tool/PMP23224

Let me know if you have any other questions, I'm happy to help!

Best,
Jerry