SLVAFO4 august   2023 TPS61299

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Overview
  5. 2Load Connected to Input Voltage
    1. 2.1 Body Diode Pass (TPS61288)
    2. 2.2 Force Pass Through (TPS61253)
    3. 2.3 Bypass (TPS61291)
    4. 2.4 Summary
  6. 3Load Disconnected to Input Voltage
    1. 3.1 Synchronous HSD FET With Switchable Body Diode (TPS61299)
    2. 3.2 Extra ISO FET to Cut-Off Leakage Path
  7. 4Summary
  8. 5References

2.4 Summary

Table 2-1 summarizes the main differences between three modes of output voltage behavior with the input when shutdown.

Table 2-1 Comparison Between Body Diode Pass, Force Pass Through, and Bypass
Voltage Drop Power Loss
Body diode pass I O U T × D C R + V D I O U T 2 × D C R + I O U T × V D
Force pass through I O U T × D C R + R d s o n I O U T 2 × D C R + R d s o n
Bypass I O U T × R d s o n I O U T 2 × R d s o n

Consider force pass through mode and bypass mode if the load device is powered by the boost input voltage when the boost converter is shutdown. Devices with force pass through mode realize the connection without integrating an extra MOSFET and have a lower cost than bypass mode in equivalent specifications. Bypass mode provides a higher-efficiency connection design and is the better choice in large load current cases.