bq79606EVM
bq79606-Q1
COML FAULTL
COMH FAULTH
UAR
T
UAR
T
Balance and Filter
Components
Balance and Filter
Components
Module
Connector
Isolation
Components
TMS570
Launchpad
bq79606-Q1
COML FAULTL
COMH FAULTH
bq79606-Q1
COML FAULTL
COMH FAULTH
Boundary Low V
oltage
Copyright © 2017, Texas Instruments Incorporated
Theory of Operation
6
SLOU471E – May 2017 – Revised April 2019
Copyright © 2017–2019, Texas Instruments Incorporated
BQ79606A-Q1 Evaluation Module
2
Theory of Operation
shows the system stack diagram.
Figure 1. System Stack Diagram
The BMS system is designed to prolong the useful life of lithium-ion cells in battery packs through passive
balancing. The battery pack is broken into a series of modules, each of which contains up to 6 cells. This
system will monitor voltages of individual battery cells and transfer charge from the module stack to an
under-charged cell or take charge from an over-charged cell and transfer it to the module stack. The BMS
allows battery-powered electric machines to use smaller battery packs and use fewer charging cycles to
perform the same amount of work. It also improves the overall lifetime of Li-ion battery packs by
preventing under- and overvoltage damage from occurring.
The typical BMS system with stacked modules has three main sub-systems, as shown in
•
Host controller - in this case a TMS570 LaunchPad™
•
A BQ79606A-Q1 configured as an isolated communication bridge device - another BQ79606EVM can
support this
•
BQ79606EVM based modules attached to cells - these can be stacked up to 64 total (including the
bridge device)
All commands and data are communicated with a host via either a UART or daisy-chain communication
connection. The BQ79606A will remain idle until a command is received from the host. The BQ79606A
can support a host PC or microcontroller (via the UART connection header) or a daisy-chain interface from
a BQ79606A-Q1 implemented as a communication bridge.