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Help for design of a battery management system

Question asked by mydadisaplumber on May 3, 2017
Latest reply on May 21, 2017 by TravisB


I'm an inventor trying to prototype a PCB for a consumer electronics invention that would use a rechargeable battery (such as Lithium-Ion).  Since your company sells battery management chips, I was looking for some technical guidance and design advice.


Attached is the sketch of the concept as I understand it.  I'd like to have multiple options to deliver the charging or powering voltage (USB, Micro-USB, etc..., so the incoming voltage would be be 5V).  Then this would feed into a battery management chip that would monitor the status of the battery and charge it if necessary.  As for the battery itself, it will provide an input to a regulator to step down to 3.3V for standard electronic components.  At certain times, an output from the electronics will open up a transistor that connects the battery to a motor that can run on 5V - 12V.  So the nominal battery voltage can be anywhere in that range, but I'm leaning towards something like this.  As an optional function, I'd like the system to also be able to charge an external device off of the battery through a USB connector.


So my questions are:


1) Does one battery management chip generally fulfill all requirements (overcharge protection, etc...) for safety certification of a consumer electronics device?  Additionally, can the same chip also monitor battery life?
2) Do you carry a battery management IC that can support multiple charging inputs from two different connectors and switch between which one is available?


3) Do you carry a battery management IC that can step up a 5V input voltage to charge a battery with a higher nominal voltage?  Or in the case of the linked battery pack, how should that be charged?  As one 7.2 V cell?  Or another way?


4) Is it possible for a battery management IC to charge an external device through the same port that it can be charged through?  Or would that require a separate port, as I have in my sketch?  Would that port require an "output" battery management system to make sure it's not drawing too much from the battery, or is a 5V regulator to a USB PCB connector like I have the right way to do it?


5) Do you have any recommendations for any other rechargeable Lithium Ion battery or battery pack that would fit these specifications?  The motor can draw 500 mA - 1A at peak startup and around 200 mA when running, and I'm hoping to get somewhere between 2-5 Ah out of the battery.


Given these specifications, do you have any battery management IC/battery combinations that would work?  At this stage, I'd only be prototyping, but this will hopefully lead to much larger production runs.