SLVAG21 April   2026 TPS61381-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2System Overview
    1.     6
    2. 2.1 Design Considerations
    3. 2.2 System Design Theory
      1. 2.2.1 Supercapacitor Charging Operation
        1. 2.2.1.1 Calculation for Backup Supercapacitor Selection
          1. 2.2.1.1.1 Design Calculations
  6. 3Test Results
    1. 3.1 Standby Operation
    2. 3.2 Charging Operation
    3. 3.3 Boost Operation
  7. 4Summary
  8. 5References

Abstract

The TPS61381 is a bidirectional boost with LDO based charger which can be used as a backup power supply during dead battery or input supply failure. The device can be used to specify smooth transition of the system to be powered by the backup supply in case of sudden power failure. The system mechanism behaves as a charger during charger operation and regulates the output voltage during power failure.

This application note is targeted to generate a warning message (dying gasp) when the system input power supply fails; this is especially important in systems such as servers, routers, access points, CPE or other system hardware with dying gasp implementation, to aid in the debugging of the system.

By sending out a final signal, the access point can help minimize the impact of the shutdown on the network, support graceful failover, and provide vital diagnostic information that can assist in maintaining network reliability and uptime. This feature is particularly useful in environments where high availability is critical.

TPS61381 supports the message generation during dead battery condition by receiving power from the supercapacitor backup, VBUB.