TIDUF46 October   2023

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Multiplexer Network and Switch Strategy
      2. 2.2.2 Cell Balancing
      3. 2.2.3 Stacked AFE Communication
      4. 2.2.4 Isolated UART Interface to MCU
    3. 2.3 Highlighted Products
      1. 2.3.1 BQ79616
      2. 2.3.2 TMUX1308
      3. 2.3.3 TMUX1574
      4. 2.3.4 TMUX1102
      5. 2.3.5 TPS22810
      6. 2.3.6 ISO7742
      7. 2.3.7 TSD05C
      8. 2.3.8 ESD441
      9. 2.3.9 ESD2CAN24-Q1
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Cell Voltage Accuracy
      2. 3.3.2 Temperature Sensing Accuracy
      3. 3.3.3 Cell Voltage and Temperature Sensing Timings
      4. 3.3.4 Cell Balancing and Thermal Performance
      5. 3.3.5 Current Consumption
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

3.3.4 Cell Balancing and Thermal Performance

The test uses a battery simulator to test the bottom BQ79616 device of the BMU at room temperature (27°C) and 3.5-V cell voltage. Auto-balancing control is used and CB FETs are enabled in an odd and even manner with a duty cycle of 30 minutes. After 30 minutes of odd or even manner cell balancing, the temperature is stable.

Table 3-10 shows the cell balancing current from a battery simulator. The power supply current to BQ79616 is near 15.3 mA. The cell current of each channel is near 109 mA.

Table 3-10 Cell Balancing Current From Battery Simulator
CELL CELL VOLTAGE (V) CURRENT (A) CELL CELL VOLTAGE (V) CURRENT (A) CELL CELL VOLTAGE (V) CURRENT (A)
8 3.5000 0.0153 16 3.5000 0.0150 24 3.5003 0.0000
7 3.5000 0.1242 15 3.5001 0.1242 23 3.5002 0.0000
6 3.5003 0.0152 14 3.5001 0.0152 22 3.5001 0.0000
5 3.5000 0.1241 13 3.5000 0.1242 21 3.5001 0.0000
4 3.4996 0.0152 12 3.5000 0.0152 20 3.5000 0.0000
3 3.5005 0.1229 11 3.4998 0.1242 19 3.4998 0.0000
2 3.5000 0.0152 10 3.5002 0.0152 18 3.5005 0.0000
1 3.4999 0.1231 9 3.5002 0.1233 17 3.5000 0.0000

The following images show the cell balancing thermal performance at room temperature. Figure 3-6 is the top side thermal image and Figure 3-7 shows the bottom side thermal image.


GUID-20231006-SS0I-S9J6-Z1FG-WPGKBFCJMSB8-low.png

Figure 3-6 Top Side of Board

GUID-20231006-SS0I-ZPM5-XRWH-4JHWQTZJNMP3-low.png

Figure 3-7 Bottom Side of Board

The maximum temperature rise is 19°C.