SLVAFU9 January   2025 TPS62840 , TPS62843

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Inverting Buck-Boost Topology
    1. 1.1 Concept
    2. 1.2 Output Current Calculations
    3. 1.3 VIN and VOUT Range
  5. 2Design Considerations
    1. 2.1 Additional Input Capacitor
    2. 2.2 Digital Input Pin Configurations
    3. 2.3 Startup Behavior and Switching Node Consideration
  6. 3External Component Selection
    1. 3.1 Inductor Selection
    2. 3.2 Capacitor Selection
  7. 4Typical Performance
  8. 5Summary
  9. 6References

Abstract

The TPS6284x family is a high-efficiency step-down converter with ultra-low operating quiescent current of typically 60nA. The device contains special circuitry to achieve just 120nA IQ in 100% mode to further extend battery life near the end of discharge. With an input voltage of 1.8V to 6.5V, the device supports multiple power sources such as 2S to 4S Alkaline, 1S to 2S Li-MnO2, or 1S Li-Ion/Li-SOCl2. These devices are well-designed for many battery powered applications, such as smart meters, medical sensor patches, industrial IoT (smart sensors) and other test and measurement equipment. The analog signal chain in such applications often requires symmetrical supply voltage or negative voltage biasing. The TPS6284x can be configured in an inverting buck-boost topology, where the output voltage is inverted or negative with respect to ground. This application report describes the inverting buck-boost topology in detail for the TPS6284x family.

Note: Precautions need to be taken when using these devices in an inverting buck-boost topology. Please review section Section 2 to understand and robustly eliminate known risk.