SLUUC37C july   2019  – august 2023 BQ75614-Q1 , BQ79616 , BQ79616-Q1 , BQ79656-Q1

 

  1.   1
  2.   BQ79616-Q1 and BQ75614-Q1 Evaluation Modules
  3.   Trademarks
  4.   General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
  5. 1 General Description
    1. 1.1 Key Features
    2. 1.2 Key Electrical Parameters
  6. 2 Theory of Operation - Stackable BQ79616EVM
    1. 2.1 Single Board
    2. 2.2 Stacked Systems
    3. 2.3 Configuring the BQ79616-Q1 EVM to be used for Lower Cell Count Applications
  7. 3 Theory of Operation - Standalone BQ75614EVM
  8. 4 Connectors
    1. 4.1 Primary Input and Output Connectors
      1. 4.1.1 Jumper Placements
      2. 4.1.2 Battery Connector
      3. 4.1.3 Host Interface
      4. 4.1.4 GPIO or Thermistor Inputs
      5. 4.1.5 High-Side and Low-Side Communications
  9. 5 Quick Start Guide
    1. 5.1 Required Devices for using the Example Code
    2. 5.2 Power Connections
      1. 5.2.1 On-Board Resistor Ladder - Power Supply
      2. 5.2.2 Using Actual Battery Cells
    3. 5.3 Connecting the EVM to TMS570 LaunchPad
    4. 5.4 Stacking BQ79616EVMs
    5. 5.5 Software
    6. 5.6 GUI
      1. 5.6.1 GUI UART Connection
  10. 6 Physical Dimensions
    1. 6.1 Board Dimensions
    2. 6.2 Board Mounting
  11. 7 BQ79616EVM Schematic, Assembly, Layout, and BOM
    1. 7.1 Schematic
    2. 7.2 Assembly
    3. 7.3 Layout
    4. 7.4 BQ79616EVM-021 Bill of Materials (BOM)
  12. 8 BQ75614EVM Schematic, Assembly, Layout, and BOM
    1. 8.1 Schematic
    2. 8.2 Assembly
    3. 8.3 Layout
    4. 8.4 BQ75614EVM Bill of Materials (BOM)
  13. 9 BQ79656EVM Schematic, Assembly, Layout, and BOM
    1. 9.1 Schematic
    2. 9.2 Assembly
    3. 9.3 Layout
    4. 9.4 BQ79656EVM Bill of Materials (BOM)
  14. 10Revision History

2 Theory of Operation - Stackable BQ79616EVM

Figure 2-1 shows the system stack diagram.

GUID-5698A2A2-84FB-4AC8-A89F-FC54F7BACA1F-low.pngFigure 2-1 System Block Diagram - BQ79616

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 16 cells. This system monitors voltages of individual battery cells and dissipates individual cell voltages through the use of internal cell balancing FETs. The BMS allows battery-powered electric machines to use smaller battery packs and fewer charging cycles to perform the same amount of work. The BMS also improves the overall lifetime of Li-ion battery packs by preventing undervoltage and overvoltage damage from occurring.

The typical BMS system with stacked modules has three main sub-systems, as shown in Figure 2-1:

  • Host controller - in this case a TMS570 LaunchPad™
  • A BQ79616-Q1 configured as an isolated communication bridge device - a BQ79600EVM or another BQ79616EVM can support this
  • BQ79616EVM based modules attached to cells - these can be stacked up to 35 total (including the bridge device)

All commands and data are communicated with a host through either a UART or daisy-chain communication connection. The BQ79616 remains idle until a command is received from the host. The BQ79616 can support a host PC or microcontroller (via the UART connection header) or a daisy-chain interface from a BQ79616-Q1 implemented as a communication bridge.

The typical flow is for the host to go through the following simplified sequence:

  1. Wakeup the BQ79616EVM board by sending a WAKEUP pulse when using the UART interface, or sending a WAKE tone when using the BQ79616EVM in a stack of other BQ79616EVM boards for a large battery pack or a BQ79616-Q1 configured as a bridge. Initialize the BQ79616-Q1 to be ready for use.
  2. Send a sample command to the BQ79616-Q1 to read the cell measurement results.
  3. The host uses the cell measurement data to calculate an average and determine the highest or lowest cells and determine the cells that are balanced.
  4. If no stop command is sent, then the BQ79616-Q1 has a built-in timeout (set by the user), after which time the discharge is stopped automatically.
  5. The host can then decide to repeat the process (back to step 2) or send commands to shutdown the BQ79616EVM and return later.