BQ25756: Secondary Battery Protection for use with Subject Charge Controller - 22.2-44.4 V Series Pack

Craig Gallimore

Part Number: BQ25756
Other Parts Discussed in Thread: BQ76952, , BQ77915

Tool/software:

Good Morning,

I am designing a battery management system for 6-12S Lithium-based (LiPo) battery pack which must accept a solar input. I have leveraged the reference design for the BQ25756 charge controller, but I also wish to incorporate cell balancing with secondary protection. I am targeting the BQ76952 Monitor and Protection IC to use in series with the BQ25756. The BQ25756 provides overall pack protection and does not necessarily need MCU programming via the I2C interface. So I am looking for a good secondary cell protection option with balancing to prolong pack life. I would also prefer the secondary protector, like the BQ76952, to be hardware programmable with the option to program via MCU, just like the BQ25756.

Can you provide feedback on whether you believe this is a good solution or perhaps provide a simpler alternative? If the latter, do you have any reference designs with these two IC's so I can speed up the design process?

Thank you for your guidance. I hope you have a great weekend.

Craig.

over 1 year ago

+1 Alexis_H over 1 year ago

TI__Mastermind 18005 points

Hello Craig,

Thank you for your patience and hope you had a great weekend yourself.

BQ76952 will suit your needs as it has both cell balancing and can be used as a secondary cell protection option. This device also has OTP and the option to use via MCU. Section 3.1 Recommended Steps for Writing OTP in Production in the BQ769x2 Calibration and OTP Programming Guide can provide specific instructions on how to do so.

There are no specific reference designs around BQ76952 with BQ25756, however, they both offer other reference designs that may be useful. TIDA-010216 - Highside MOSFET Control and TIDA-010216 - LowSide MOSFET Control are reference designs specifically for BQ76952. TI Reference Design Library may be able to assist you in looking up other reference designs.

A simpler alternative that you could potentially also use is the BQ77915. You would, however, need to stack the device and it does not have OTP. Stacking with BQ77915 would be a good resource to use for that.

Best Regards,
Alexis

0 Craig Gallimore over 1 year ago in reply to Alexis_H

Prodigy 70 points

Hi Alexis,

Thank you for the quick reply. It is good to know I am on the right track, so I appreciate your validation and recommendations. Have a great rest of your week!

Craig.

Power management

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BQ25756: Secondary Battery Protection for use with Subject Charge Controller - 22.2-44.4 V Series Pack