Other Parts Discussed in Thread: BQ79614-Q1
Hi,
I use the BQ79614-Q1 chip in a electric race car build by students. And everything works fine until we power on the inverters to drive our motor which introduces a lot of noise on the daisy chain communication and communication with the stack devices is gone completely and doesn't comeback until we shutdown the inverters.
We use a 12 stack devices with each powered by 12 cells in series and 1 BQ79614 chip as base device powered by an isolated 600V -> 24V DCDC .We connected the UART of the base device straight to the MCU (so without digital isolator in between because the MCU is also powered by the 24V).
The daisy chain communication is isolated with isolation caps and 2 CMC (100uH and 470uH). I strictly followed the datasheet when designing to prevent the problem we are having now from happening.
We also bought the development board and when we connect this board in stead of our own PCB we still have the problem. We can also clearly see voltage spikes on the communication line at a frequency of 16khz (switching frequency of the drives) when measuring between comm_p and comm_n.
If you might know how to solve this or when you need more information please contact us.
In the picture you can see the schematic of the daisy chain communication (termination resistor is not placed since we use ring architecture)
