BQ79612-Q1: MCUs on every stack device and not just the bottom device, possible?

Jaideep Sharma

Part Number: BQ79612-Q1

Hello,

Looking to get answers to a few questions:

For reference project details are;

Stack application where each module is 12S
Up to 10 modules stacked.
Using BQ79612

In almost all diagrams I see that the only the base device has an MCU connected to it.

Let's say I want an MCU on all modules in the stack where each MCU connects to the RX/TX pins to the corresponding module's BQ chip.

Can each module's MCU then read individual cell voltages local to that module and trigger an active balancing circuit?

I think this should be possible but I didn't see anything about stack devices also having MCUs connected to them in the datasheet.

Thanks

over 1 year ago

0 Harrison Yang over 1 year ago

TI__Prodigy 510 points

Hi Jaideep,

I think you are talking about the fig1 situation.

The MCU can read the local cell voltage and balance the local cell.

You can choose the architecture in Figure 2 and Figure 3 because the cost maybe lower.

0 Jaideep Sharma over 1 year ago in reply to Harrison Yang

Prodigy 10 points

Hi Harrison,

Yes I mean the configuration in figure 1 but also with all BQ chips being interconnected with COMH and COML (Full Ring).

So separate MCU on for all BQs and all BQs being interconnected with the daisy chain connection also.

We need an MCU on for all BQs because each MCU controls active balancing for one set of 12 cells. Extra cost is not a problem.

Thank You for your response.

+1 Harrison Yang over 1 year ago in reply to Jaideep Sharma

TI__Prodigy 510 points

Jaideep,

UART is the control interface of 612 and cannot be used to transmit other message. You can use SPI Master function of 612 for communicating with MCU.

The fig5 is a common solution. It doesn't need a daisy chain.

0 Jaideep Sharma over 1 year ago in reply to Harrison Yang

Prodigy 10 points

Harrison,

Thanks for the info on the SPI master feature. We might go with that approach. Or with the isolated CAN approach to connect all MCUs

Am I correct to assume that the approach below will not work for our purpose as the UART interface cannot transmit cell voltage information and is only be meant to be used with a single host?

Like the image below

0 Harrison Yang over 1 year ago in reply to Jaideep Sharma

TI__Prodigy 510 points

Jaideep,

Fig6 can't work. Because the BQ79612 can't transmit command to MCU.

Power management

Power management forum

BQ79612-Q1: MCUs on every stack device and not just the bottom device, possible?