SLUUBT4B June   2018  ā€“ June 2025 BQ40Z80

 

  1.   1
  2.   Description
  3.   Features
  4.   4
  5. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Ordering Information
    4. 1.4 BQ40Z80 and BQ771807 Circuit Module Performance Specification Summary
  6. 2Hardware
    1. 2.1 BQ40Z80EVM Quick Start Guide
      1. 2.1.1 Items Needed for EVM Setup and Evaluation
      2. 2.1.2 Software Installation
      3. 2.1.3 EVM Connections
      4. 2.1.4 Update Firmware
    2. 2.2 Battery Management Studio
      1. 2.2.1 Registers Screen
      2. 2.2.2 Setting Programmable bq40z80 Options
      3. 2.2.3 Calibration Screen
        1. 2.2.3.1 Voltage Calibration
        2. 2.2.3.2 Temperature Calibration
        3. 2.2.3.3 Current Calibration
      4. 2.2.4 Chemistry Screen
      5. 2.2.5 Firmware Screen
        1. 2.2.5.1 Programming the Flash Memory
        2. 2.2.5.2 Exporting the Flash Memory
      6. 2.2.6 Advanced Comm SMB Screen
  7. 3Hardware Design Files
    1. 3.1 bq40z80EVM Circuit Module Schematic
      1. 3.1.1 Precharge
      2. 3.1.2 Predischarge
      3. 3.1.3 LED Control
      4. 3.1.4 Emergency Shutdown
      5. 3.1.5 Testing Fuse-Blowing Circuit
    2. 3.2 Circuit Module Physical Layouts
      1. 3.2.1 Board Layout
      2. 3.2.2 bq40z80RevA Schematic
    3. 3.3 bq40z80EVM Bill of Materials
  8. 4Additional Information
    1. 4.1 Trademarks
  9. 5Related Documentation from Texas Instruments
  10. 6Revision History

3.1.1 Precharge

The EVM provides a power resistor and FET to support a reduced current precharge path to charge the pack when cell voltages are below the precharge voltage threshold. This reduces heating that can lead to cell damage or reduced operating lifetime. For a 7-series cell application, the FET must be rated above the max voltage, and, for this reason, the CSD18504Q5A was chosen. The TI CSD18504Q5A is a 50A, 40V device with Rds(on) of 5.3mĪ© when the gate drive voltage is 10V. The user can change R1 to setup the precharge current to a different value. R1 is calculated to limit the precharge current to the desired rate. Be sure to account for the power dissipation of the series resistor. The pre-charge current is limited to (VCHARGER ā€“ VBAT)/R1 and maximum power dissipation is (Vcharger ā€“ Vbat)2/R1.