[DISCLAIMER] : I am not sure if a post I did a couple of minutes ago did get through, so I'm re-posting it. If this is a duplicate, please ignore it and delete it. Thank you
Hello there!
The company I work for recently purchased the BQ24770EVM-540 charger board alongside the EV2300 interface board. We are having a really rough time using these two products together and I'll list my issues next. Details on the target application down below.
- First of all, even though the charger board works with both EV2300 and EV2400 interface boards, maybe a good emphasys should be made on buying the latter since the former one's drivers are already obsolete for current 64-bit OS. It is mentioned in the User guide of the charger board, but it is not mentioned on the front end webpage of the board and this lead the person of my team leading the purchase to buy the "most complicated" option.
- Second, I've found some inconsistencies between the labeling on the board and the References on the User Guide. I'll put an example but it should be noticed that this kind of typo goes along the whole User Guide, so I suggest a better revision of it before releasing it. So, as I said, if you check page 8 of the User Guide, section 3.1.3; there are a list of voltages to be checked in order to verify the correct behavior of the board. However, there is a line that says: "V(TP16(CELLS)) = [...]". On the board we purchased, TP16 corresponds to VCC and CELLS is actually called CELL and labeled TP11. This is not a major issue but it can lead to misunderstandings if one does not pay attention. In the next line, TP6 is said to be assigned to ACDET, whilst on my board ACDET is TP7. So on and so forth, these kind of mistakes are made throughout the whole document.
- Third, I can't find a proper explanation of the CMPIN/CMPOUT pins of the chip. I just emailed TI support requesting a full datasheet of the chip. I hope this will help. However, that doesn't explain why section 1.3 (Switch S1) does not explain the behavior of the board given certain position of the switches.
- Fourth, so far I have understood that CELLS configuration cannot be made dynamically (via software). It has to be set via a couple of resistors. Correct me if I'm wrong, please. I am also hoping the full datasheet will help me clarify how to make this configuration. I can't find anything about this on the User's Guide either. My board seems to be configured for 2 cells and I haven't found the way to change it to what I need: 4 cells. Somewhere on the User's Guide it should say the values of R28/R29, R30/R31 and R24/25 in order to configure the board for 1, 2, 3 and 4 cells. The only hints about this configuration are found in Section 2.2.1 when the reader is warned about the resistor pairs possibly not being the correct one. Nevertheless, it is not said what this "correct" value actually is.
- Fifth, I have downloaded BQStudio v1.3.52. I downloaded (from these forums) a 64-bit version of the EV2300 drivers. However, when I connect all the boards as shown in Figure 3 of the User Guide and follow the setup instructions of Section 3, I can't communicate with the charger board using the EV2300 board. For some reason, it looks like it is propperly enumerated by the PC but it does nothing. Every time I try to read the registers, I get en ACK error. I have it configured to read via SMBus protocol (setting the Target Address as 0x12) and I have connected the provided cable from the SMBC/SMBD pins to the BQ24770EVM board's SCL/SDA pins respectively. I have connected the external 3.3V Power Supply to the 3.3V pin, as requested, and a 19.5V Power Supply to the Vin Pin. So, what can I be doing wrong here?
I would really appreciate some help with these boards. Just to put some context, the end application is a high power charger. The product we're working on uses a 4S 40Ah battery. We can charge the battery with up to a 10A current. And given the high capacity, we want the charger to have as high current throughput as possible. That is why we got interested on the BQ24770. However, for this charger to work for us, we need to be able to work with it fully. Otherwise, we can't make mass production of our product with a BQ24770.
For more information on the end application, I'd rather be contacted via mail to juan.rodriguez@ebotlution.com.
Thanks again.
