BQ27510EVM: Part is obsolete and I am looking at several replacements

Hi Craig,

Can you please tell me more about what you are looking for and kind of battery you are using? This will allow us to get a better idea of what gauge to recommend.

Firstly, the bq27510 has an external sense resistor, external thermistor, SON package, can be programmed with any ChemID.

bq27z558 - high and low side sense resistors, internal and external temperature sense, DSBGA package, can be programmed with any ChemID.

bq27441 - external sense resistor, internal temperature sense, VSON package (most similar to SON), only preprogrammed ChemID can be used.

bq27426 - external sense resistor, internal and external temperature sense, YZF package, only 3 preprogrammed ChemIDs can be used.

Regards,

Anthony Baldino

We have a Li-ion battery and this gauge will live with the device not with the battery pack.  The packs are removable in our system.

Small package would be a plus.  We are willing to switch to a high side current sense.  If the sensor is internal then we will have a separate diff amp to measure high speed current data which will double utilize the internal resistor.  Any issues with that?

I'm looking at the BQ27427, but I'm not sure if we can live with just the 3 preprogrammed profiles.  I'd like to learn more about how the chemistry data is utilized to create the SOC lookup table.  

If we need the full programmable feature set like the BQ27510 had would the BQ27532 be my best option?

What is the anticipated time for continued availability on the BQ27427 & BQ27532? 

Currently the 27532 is being loaded with chemistry ID 0116 how close is that to what is available in the BQ27427 CHEM ID 1202.

Is there someone in New Hampshire that can sit down with me and provide some direct help?

Hi Craig,

Understood, thank you for clarifying.

Regarding the preprogrammed profiles, we offer the GPCCHEM tool that matches the battery you plan to use for the application to the closest applicable ChemID in our database. More information regarding this can be found below:

https://www.ti.com/tool/GPCCHEM 

If possible, can you please confirm if your company has a designated TI Technical Sales Representative? If not, please let me know and I can put you in touch with someone in the New Hampshire area that can provide insight to these concerns.

Regards,

Anthony Baldino

I don't believe we have a dedicated sales rep after asking around no one was identified.

The GPCCHEM tool seems to be a possible pathway to taking a battery and translating it into a CHEMID but it requires profiling the battery and of course there is variability in the age of the cells, the particular cell, etc.  

What I need is a method to understand what the CHEMID does and be able to compare what we have been using for years with the limitations of the BQ27427 part which only allows for (1) CHEMID (1202).  

Hi Craig,

Yes, the main purpose of the GPCCHEM tool is to find a viable ChemID for the battery you are looking to use in application. However, the GPCCHEM tool also produces the % max DOD Error of the inputted cell compared to many different ChemID profiles. It could be a useful tool since it will tell you whether a flash gauge needs to be used for the most accurate ChemID to be programmed, or if there are options within the preprogrammed ChemIDs and which ones can be used.

The purpose of the ChemID is to be the graphical basis of what the OCV measurements taken during gauging are compared against. The ChemID is typically taken at the point where the battery is inserted into the application (usually new), to where when OCV measurements are taken by the gauge, allowing for the chemical capacitance and resistance of the cell to be predicted and learned by the gauge. This allows for the gauge to accurately measure the State of Health, State of Charge, and other parameters of the cell.

Attached is the Battery Gauging Algorithm Comparison file. In section 6, there is more information on the Impedance Track Algorithm:

https://www.ti.com/lit/pdf/sluaar3 

There is also more information about the ChemID in the Introduction of this document:

https://www.tij.co.jp/jp/lit/pdf/slua903 

Regards,

Anthony Baldino

I still have some un-answered questions:

• Is there a local AFE that could stop by for a 1:1 meeting to speed up the communication.  I appreciate your help Anthony but we are looking to set a path and update a layout and neither of those things can happen until we have closure on these issues.
• What is the anticipated time for continued availability on the BQ27427 & BQ27532? 
  • If we design in the BQ27532 (2016) are we going to be back here in 2 years?
• What is the difference between CHEM ID 116 & 1202?

New question:

• What is the ADC difference between the BQ27427 & or existing bq27510?  In current design we have a filter due to current with a short pulse duration.  Is the BQ27427's integrating A/D accurate with pulse currents of short duration?

Thank you,

/Craig

Hi Craig,

I have reached out to the designated FAE under your companies account to see if there was a local representative area that you can have a 1:1 meeting with regarding these issues. They should be reaching out to you shortly.

Regarding the anticipated time for continued availability on bq27427, it is one of our newer parts and will be available for a decent amount of time. Attached is our Product Life Cycle page and the necessities that need for a product to be discontinued:

https://www.ti.com/support-quality/quality-policies-procedures/product-life-cycle.html#:%7E:text=We%20have%20established%20clear%20guidelines,at%20least%2010%20years%2C%20and 

The difference between ChemID 116 and 1202 is the cell that the profile was taken on. The ChemID database is a collection of cells that have been profiled in house.

Regards,

Anthony Baldino