SNVAA63 March   2023 TPSM365R6

 

  1.   Abstract
  2.   Trademarks
  3. 1Inverting Buck-Boost Topology
    1. 1.1 Concept
    2. 1.2 Output Current Calculations
    3. 1.3 VIN and VOUT Range in Inverting Configuration
  4. 2Design Considerations
    1. 2.1 Additional Bypass Capacitor and Schottky Diode
    2. 2.2 Start-up Behavior and Switching Node Consideration
  5. 3External Components
    1. 3.1 Capacitor Selection
    2. 3.2 System Loop Stability
  6. 4Typical Performance
  7. 5Digital Pin Configurations
    1. 5.1 Digital Input Pin
    2. 5.2 Power-Good Pin
  8. 6Conclusion
  9. 7References

6 Conclusion

The TPSM365R6 buck power module can be configured into an IBB topology to generate a negative output voltage by switching the output and ground connections. The input voltage range is lowered because the device now has a reference point set to the negative output voltage rather than ground. Additionally, the inductor peak current is much higher, effectively lowering the recommended maximum output current operating range for all output voltages. Converting an original buck topology into an IBB topology will result in a lowered input voltage range and maximum output current. This application report explains the IBB topology and how to select the proper external components to keep the system stable. Data from the test circuits are measured and provided.