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BQ51050B: Protective Battery Measures

Other Parts Discussed in Thread: BQ2970, BQ51050B

Hi all,


My team and I are working on developing a wearable device (like a heart rate monitor with IP68 dust/waterproofing) and we're utilising wireless charging for our 3.7V 350mAh non-removable battery. It's like a heart rate monitor that will be worn against the skin and will be required to go through the washing machine weekly (embedded in fabric). The enclosure will be very hard plastic with epoxy sealing.


We'll be using TI's BQ51050B IC and whilst it performs the roles of wireless receiver and battery charger in one IC, I noted that it does not perform the full suite of voltage, current and temperature protections that a good battery management system (like the BQ2970) does.


I have reviewed a few different safety standards including IEC, UL and CE and they all discuss the potential hazards however don't give a definitive verdict as to whether a BMS would be advisable for small wearables specifically.


Given the experience on this forum, would the BQ51050b as the PCB charger IC and a protection IC on the battery by our battery supplier be sufficient for safety or should something else be included in the circuitry of our PCB as well?

Kind Regards,
Andy

  • Hi Andy,

    I am not familiar with the bq51050B for that i would recommend that you post into the appropriate forum (charger forum) to ask about what protection features it has. In terms of bq2970 it is a device widely used in single cell application as primary protection. In regards to answering your question on asking whether both ICs will make your battery safe, i would say that both ICs are meant for different purposes and at times a charger IC will include some OVP protection or some protections, but they are usually on the system side not the battery pack side. For protection to be "enough" this will have to be up to you as the designer to make sure it satisfies the standard(s) you are trying to acquire.

    Thanks

    Miguel