BQ76940: creating a power system for AGV

Sergei Zob

Part Number: BQ76940

Faced the challenge of a non-standard power system for a mobile platform. I have no cooling. I do not have the possibility of placing large switching devices. Tell me the diagram below is real? I can not put a large relay. I have a lot of cells 18650 size. I need to avoid dropping containers due to parattelnogo packages. I will be glad to any advice

over 5 years ago

0 Matt Sunna over 5 years ago

TI__Guru* 80803 points

Hi Sergei,

I'm not sure where this picture is from. Depending on the number of cells in series, you can select the right type of device for your needs. If you want to learn more about the BQ76940, you can read more about it in the product folder, or you can start with this video about building a schematic using this device: https://training.ti.com/how-create-schematic-bq76920-bq76930-and-bq76940 The reference designs using this device do not use relays.

Best regards,

Matt

0 Sergei Zob over 5 years ago in reply to Matt Sunna

Prodigy 30 points

OK, thanks for the answer . Speaking of the relay, I was talking about the device for comutation of charge and the device for disconnecting the load from the battery if it lights up. I think that would charge each successive line. and balance as one. Is that possible?

0 Matt Sunna over 5 years ago in reply to Sergei Zob

TI__Guru* 80803 points

Hi Sergei,

The common approach is to use FETs for charge and discharge. You can read more about how this works for the BQ76940 in Section 6 (FET Drive) of this app note: http://www.ti.com/lit/an/slua749a/slua749a.pdf. This app note also has a detailed section on Cell Balancing (Section 4) where you can see how it works for this device.

I hope this helps,

Matt

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BQ76940: creating a power system for AGV