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

2.4.2 Data Memory Configuration

The gauge's Data Memory is configured in bqStudio from the Data Memory window. This window is shown below in Figure 2-10.

GUID-9D25783A-C40A-4036-BD6A-9F094B54DDBB-low.pngFigure 2-10 Data Memory View in bqStudio

The necessary data memory configurations are made in this screen, using only the [Advanced Charging Algorithm] and [Gas Gauging] sections of the data memory window. Use the Filter/Search box to find specific parameters. Use the Write All button to write data memory parameters that have been changed on this screen to the gauge. Use the Read All button to read the current data memory configurations from the gauge and verify a successful write. Make sure that each value is programmed in the correct unit, indicated in the third column for each data memory parameter.

The following are the data memory values that are programmed:

  • [Advanced Charging Algorithm][Termination Config][Charge Term Taper Current]: This value os set slightly higher than the actual taper current between C/10 and C/100. This value is also higher than the [Chg Current Threshold] value.
  • [Gas Gauging][Design][Design Voltage]: This value can be found in the battery data sheet as the nominal or average voltage.
  • [Gas Gauging][Design][Design Capacity mAh]: This value can be found in the battery data sheet as battery capacity and is often referred to as C.
  • [Gas Gauging][Design][Design Capacity cWh]: This value is the battery capacity in centiwatt hours. This value in the battery data sheet. Or can be found by multiplying the capacity in mAh by the terminal voltage in Volts, then dividing by 10.
  • [Gas Gauging][IT Cfg][Term Voltage]: This value can be found in the battery data sheet as the terminal voltage. This is the lowest voltage that the gauge charges to.
  • [Gas Gauging][Current Thresholds][Dsg Current Threshold]: This current value is where the gauge recognizes that the battery is being discharged. Set this value below C/10, as a positive number. The gauge interprets as a negative.
  • [Gas Gauging][Current Thresholds][Chg Current Threshold]: This current value is where the gauge recognizes that the battery is being charged. Set this value below C/10 and also lower than the Charge Term Taper Current.
  • [Gas Gauging][Current Thresholds][Quit Current]: This value is where the gauge enters relax mode and is less than C/20 and lower than the [Dsg Current Threshold] and [Chg Current Threshold].

Figure 2-11 shows a visual representation of the current during the course of a learning cycle relative to the data memory current parameters set.

GUID-4F5EE091-94D6-4132-88A7-E8837A54E26E-low.pngFigure 2-11 Graph of Learning Cycle Current