SLUAAN7A April   2023  – November 2024 TPS1211-Q1 , TPS1214-Q1 , TPS4811-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1TPS1211-Q1 High Side Switch Controller Overview
  5. 2System Design Examples with Reverse Battery Protection
    1. 2.1 Design 1: Power Distribution Box
    2. 2.2 Design 2: Body Motors Load Driving
    3. 2.3 Design 3: Heater Load Driving
      1. 2.3.1 Reverse Battery Protection with MOSFET OFF
      2. 2.3.2 Reverse Battery Protection with MOSFET ON
  6. 3Summary
  7. 4References
  8. 5Revision History

Reverse Battery Protection with MOSFET OFF

Figure 2-6 shows TPS12110-Q1 application circuit to drive heater loads. PWM signal can be applied to the INP pin for controlling the ON or OFF duration of the load.

Since there is no reverse blocking MOSFET in the power path, during the reverse battery condition there is reverse current flow from PGND, load, MOSFET Q1 body diode and to the battery as shown in the Figure 2-6.

In this condition, the MOSFET Q1 can see high-power dissipation and can damage due to excess heat and current stress on the body diode. Adding a reverse blocking MOSFET can be one technical design to avoid this stress and protect the MOSFET Q1. However, the blocking MOSFET characteristics like RDSON, current rating must be the same as a MOSFET Q1. This design results in double the cost of the power stage and increases the design size which is not acceptable in high-current system designs.

 TPS12110-Q1 Application
                    Schematic for Driving PTC Heater Load with MOSFET OFF During Reverse Battery
                    Condition Figure 2-6 TPS12110-Q1 Application Schematic for Driving PTC Heater Load with MOSFET OFF During Reverse Battery Condition