SLUAAS8 November   2024 TPS1210-Q1 , TPS4810-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2BMS System Overview
  6. 3Application of TPS1210-Q1 and TPS4810-Q1 to accomplish the Battery Disconnect Switch Design
    1. 3.1 Separate Charge and Discharge FET Control
    2. 3.2 Charge, Discharge FET Control With Pre-Charge Functionality
    3. 3.3 Current Sensing for Short Circuit Protection
    4. 3.4 Reverse Polarity Protection
    5. 3.5 Diagnostics
      1. 3.5.1 FET Diagnostics
      2. 3.5.2 Short Circuit Protection Comparator Diagnostics
      3. 3.5.3 Fault Indication
  7. 4Summary
  8. 5References

2 BMS System Overview

Battery management system (BMS) monitors, protects, and optimizes battery performance of the electric vehicle battery.

Figure 2-1 and Figure 2-2 shows the block diagram of the BMS system.

BMS System With High Side Current SensingFigure 2-1 BMS System With High Side Current Sensing
BMS System With Low Side Current SensingFigure 2-2 BMS System With Low Side Current Sensing

The BMS system typically comprises of cell monitor and balancing unit to diagnose cell voltages and temperature, balance cell characteristics and communicate with the system controller. A shunt resistor is placed either on the high side or on the low side for sensing current through the battery cells for couloumb couting and protection.

Battery disconnect switches disconnect the battery cells from the charger and the loads during system fault conditions such as over temperature of the cells, over currents during charging and discharging making sure EV safety during parking, charging, and discharging.

The Switches are in a back to back configuration to block the current in charge and discharge directions during the system fault. Based on the end-application goals the back to back switches can need to be controlled separately or together at the same time.

Some system design architectures for the battery disconnect switches based on the TPS1210-Q1 and TPS4810-Q1 high side drivers and the associated end-application goals are outlined in the following sections.