SLUUC57B october   2019  – august 2023 BQ79600-Q1

 

  1.   1
  2.   BQ79600-Q1 Evaluation Module
  3.   Trademarks
  4. 1General Description
    1. 1.1 Key Features
    2. 1.2 Key Electrical Parameters
  5. 2Theory of Operation
    1. 2.1 Compatibility with Battery Monitoring Devices
  6. 3Connectors
    1. 3.1 Primary Input and Output Connectors
      1. 3.1.1 Jumper Placements
      2. 3.1.2 Power Supply
      3. 3.1.3 Host Interface
      4.      14
      5. 3.1.4 High-Side and Low-Side Communications
  7. 4BQ79600EVM Quick Start Guide
    1. 4.1 Required Devices for Using the Example Code *Not Available Yet*
    2. 4.2 Power Connections
    3. 4.3 Connecting the BQ79600EVM to TMS570 LaunchPad
    4. 4.4 Connecting BQ79600EVM to BQ79616EVM
    5. 4.5 Connecting BQ79600EVM to BQ79606EVM
    6.     22
    7. 4.6 Software *Not yet available*
    8. 4.7 GUI
      1. 4.7.1 GUI UART Connection
  8. 5Physical Dimensions
    1. 5.1 Board Dimensions
    2. 5.2 Board Mounting
  9. 6Schematics, Assembly, Layout, and Bill of Materials (BOM)
    1. 6.1 Schematics
    2. 6.2 Assembly
    3. 6.3 Layout
    4. 6.4 Bill of Materials (BOM)
  10. 7Revision History

2 Theory of Operation

Figure 2-1 shows the system stack diagram.

GUID-BD338180-E6A1-41B6-A4B5-64FC23372A6C-low.pngFigure 2-1 System Block Diagram

The typical BMS system consists of a Battery Management Unit (BMU) and one or more stacked Cell Monitoring Units (CMU). The BMU must be isolated from the CMU using transformers to keep the high voltage of the stacked battery modules isolated from the BQ79600 bridge device and the microcontroller.

The typical simplified bridge circuit in the BMU system has three main components, as shown in Figure 2-1:

  • Host controller - in this case a TMS570 LaunchPad™
  • Power management IC (PMIC)
  • BQ79600-Q1 isolated communication bridge device - in this case a BQ79600EVM

The BQ79600 device can be powered from the 12-V battery directly or from the PMIC. When powered from the 12-V battery, the reverse wake-up function on the BQ79600 can be used in a ring architecture to wake up the PMIC and the microcontroller with an unmasked fault is detected.

All commands and data between the host and the BQ79600 bridge device are communicated through either a UART or a SPI communication connection. The BQ79600EVM can support a host PC or microcontroller (via the FTDI connection header, the USB2ANY connection header, or the LAUNCHXL2-TMS57012 LaunchPad boosterpack). The BQ79600 remains idle until a command is received from the host. All commands and data between the BQ79600 and the cell monitoring devices, such as BQ79616, is communicated through the daisy chain interface.

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

  1. Wake up the BQ79600EVM board by sending a WAKE-UP pulse using the UART/SPI interface.
  2. Send a send wake up command to the BQ79600EVM to wake up the stacked cell monitoring devices.
  3. Autoaddress and initialize bridge and stacked devices.
  4. Send a sample command to the BQ79616-Q1 to read the cell measurement results.
  5. The host uses the cell measurement data to calculate an average and determine the highest or lowest cells and determine the cells that must be balanced.
  6. 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.
  7. The host can then decide to repeat the process (back to step 4) or return later. When using the BQ79616-Q1 in a ring architecture, the host can enable the sniffer detector on the BQ79600-Q1 and the FAULT tones in the BQ97616-Q1, then send the stacked devices to SLEEP and the bridge and itself to shutdown, and the AUTO reverse wake-up function wakes up the PMIC and MCU if an unmasked fault from the stacked devices is detected by the bridge.