bq28z610 FETs Not Initializing

Hi Blake..

You should click the FET_en command to turn on  the fets. If the fets are enabled the chg and dsg flags will be red. if the are dischabled, they will be green and the XDSG and XCHG flags will be set. See snippet below:

thanks

Onyx

Onyx,

Thank you much for the reply. I have a follow up question. The issue is that the board is not talking to the EV2300. In the image below, Data, Clock and VSS

lines are connected between the bq28z610EVM and EV2300 (VDD) is not connected as described in the EVM guidance document. Internal resistor pull-ups are being used on the Clock and Data lines. A single

Li-ion cell is connected across 1N and 1P with 1P shorted to 2P.

When starting the bqStudio software and selecting the right fuel gauge, this is the result I get.

After clicking "Ok" from the error box in the first screenshot, the program attempts to connect but fails as seen in the next two images.

USB communication between the program and the EV2300 seem to be good.

The VC2 line on the board is receiving voltage so I believe that the chip is powered on and therefore able to communicate over SMBus. Are there any steps you

might recommend to get bqStudio talking with the chip? I did notice that there are two options for the bq28z610, "2610_0_11" and "2610_0_17". I did try both unsure if

 that would make a difference. Thank you for your time.

-Blake

Thank you very much for your help Onyx. I had been using the SMBus port for a different battery pack BMS board so my brain definitely over looked that in the user guide. I have the fuel gauge IC talking to the bqStudio software now. The FET_EN did not seem to work, however when I tried sending the command "21" via Manufacturer Access and refreshed, that did successfully enable the CHG FET but the DSG remained green.

I pressed the "wake" switch like you suggested again, but will not turn on the pack terminals, which should be due to the DSG FET not turning on. Is there a way to turn both FETs on? FET_EN returned N/A.

Thank you for your time.

Yep, your suspicion was correct. A cell under voltage (CUV) condition was tripped causing the discharge FET to remain off. I figured this was due to my single cell wiring configuration. I added another cell in series and now the output is sustaining the pack voltage so that issue is fixed. The next step, since I need a single cell configuration, was to switch the CCO flag according to the user guidance document. In the "Data Memory", "Settings", "DA Configuration" menu, the CCO flag was by default set to hex code 11 and was red. I changed this to green and the hex code changed to 10. The fuel gauge didn't seem to care, however I would expect the CHG FET to turn off due to a COV condition. Here are some screenshots to clarify.

Figure 1. DA Configuration set to two cells in series.

Figure 2. Two cell DA Configuration with two cells connected on input terminals.

Figure 3. DA Configuration set to 1 cell

Figure 4. Two cells in series was left connected when the DA configuration was set to one cell and the registers were refreshed as shown. The COV flag did not trigger as I would have expected since I had two cells connected.

Figure 5. One cell DA Configuration with a single cell connected.

Figure 6. Two cell DA config with single cell connected Test 1

Figure 7. Two cell DA config with single cell connected Test 2

So for recap...

Here are my questions based off the images:

1) What does the CCO bit stand for? (figure 1) I was not able to find any information on "CCO" in the technical reference document for the bq28z610 or online. It is only briefly mentioned in the user guide.

2) Why is the COV flag not triggering when the CCO bit is set for single cell config and two cells are connected? (figure 4)

3) Why is the "PACK pin voltage" always lower than the battery icon in the dashboard? (figure 5) Multimeter voltage measurement on the pack terminal on the board verifies that the battery icon is correct, not the "PACK pin voltage" value.

4) This last question regards figures 6 and 7. I switched back to the two cell DA config setting with one cell connected and kept on waking up the IC and refreshing the screen just to see what would change and I noticed two things. First, XDSG, SS, and DSG kept changing almost every time I woke up the chip and refreshed the screen. Second, in figure 6, DSG FET is on according to the screen and the CUV condition is met. This indicates that the IC recognizes that the voltage is too low (because it is expecting a two cell battery) and yet is still allowing the battery to discharge which is obviously not good, unless this is a false positive. I'm not really concerned about this since I will be using the fuel gauge in a single cell configuration, but thought I would mention it.

I apologize for the long post, but I hope I gave sufficient information to back up my questions.

Thank you for your time Onyx.

-Blake