Other Parts Discussed in Thread: EV2400
Tool/software:
Hi there—our design connects an active-low push button to the /SHUTDN pin of the gauge; we use it as a debug function to effectively remove the battery without disassembling the device.
When this button is pressed, the pack voltage falls to zero roughly 50% of the time; the pack voltage is not restored until the button is released and pressed again. This behavior matches our expectation and intent. The other 50% of the time, however, the pack voltage is automatically restored after 500 ms:
Given the consistent nature of the timing, I loosely suspect this behavior is related to the charger detection function. I changed EMSHUT_EXIT_VPACK from 1 to 0 as follows:
Doing so appears to have solved this problem—the pack voltage decays to zero 100% of the time, and is not restored until the button is released and pressed again.
What's unclear, however, is why pack detection has any impact here. Our application preserves the default charger detection threshold of 3 V—based on the capture, however, our pack voltage clears this threshold well before the 500-ms sample period expires. Is the behavior I've described expected?
Thank you in advance for your support—in case I can clarify any of my observations, please let me know.