SLUUCW4 November   2023 BQ27Z558

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  7. 2Hardware
    1. 2.1 Hardware Setup
      1. 2.1.1 Hardware Requirements
      2. 2.1.2 Connecting the BQ27Z558 Circuit Module to a Battery Pack
      3. 2.1.3 EVM Jumpers Description
    2. 2.2 Chemical ID
      1. 2.2.1 Chemical ID Selection Process Description
      2. 2.2.2 Hardware Requirements and Setup
      3. 2.2.3 Logging Data in bqStudio
      4. 2.2.4 GPCChem Tool
      5. 2.2.5 Programming a Chemical ID
      6. 2.2.6 Further Resources for Chemical ID Process
    3. 2.3 Calibrating Gauge Measurements
      1. 2.3.1 Voltage Calibration
      2. 2.3.2 Current Calibration
    4. 2.4 Learning Cycle and Golden Image
      1. 2.4.1 Learning Cycle Process Description
      2. 2.4.2 Data Memory Configuration
      3. 2.4.3 Learning Cycle Steps
      4. 2.4.4 Low Temperature Optimization
      5. 2.4.5 Creating the Golden Image File
      6. 2.4.6 Programming the Golden Image File
    5. 2.5 BQ27Z558-Based Circuit Module
      1. 2.5.1 Circuit Module Connections
      2. 2.5.2 Pin Description
  8. 3Software
    1. 3.1 Software Setup
      1. 3.1.1 System Requirements
      2. 3.1.2 Software Installation
    2. 3.2 Troubleshooting Unexpected Dialog Boxes
    3. 3.3 Using bqStudio
      1. 3.3.1 Starting the Program
      2. 3.3.2 Setting Programmable BQ27Z558 Options
    4. 3.4 Gauge Communication
      1. 3.4.1 Advanced Communication in bqStudio
      2. 3.4.2 Standard Data Commands
      3. 3.4.3 Manufacturer Access Commands
      4. 3.4.4 Further Resources on Gauge Communication
  9. 4Hardware Design Files
    1. 4.1 Schematic
    2. 4.2 PCB Layout
    3. 4.3 Bill of Material
  10. 5Additional Information
    1.     Trademarks

2.4.1 Learning Cycle Process Description

The learning cycle process consists of charge – relaxation – discharge – relaxation – charge while certain data memory parameters are set in the gauge, enabling the gauge to begin the cycle and accurately recognize when state changes have occurred over the charge/discharge process. Through the course of the learning cycle, the [LStatus] register updates as different states are achieved, marking three points in the progression of the learning cycle.

The first [LStatus] update goes from 0x00 to 0x04 when the gauge has had the Impedance Track bit enabled, allowing the learning cycle to begin. [LStatus] goes from 0x04 to 0x05 when the post-charge relaxation has allowed the battery to relax enough so that the change in voltage is very low (dV/dt < 1 µV/s). The [REST] flag is set indicating that the battery has adequately relaxed. The final [LStatus] update to 0x06 happens after the second discharge when the change in voltage is very low.

For more details on the register updates and flags set at each point in the learning cycle, refer to Section 3.2 of the Achieving the Successful Learning Cycle document found on ti.com.

For more details on the learning cycle registers for the BQ27Z558 specifically, see the BQ27Z558 Technical Reference Manual found on ti.com.