Understanding the Start-up Behavior of the TPS61178x (Rev. A)
For the conventional synchronous boost converter, the output voltage follows the input voltage when the
converter is disabled. This behavior increases power loss due to the leakage current flowing through the
feedback divider and the post-load. The TPS61178x device is a 20-V, 10-A boost converter that integrates
a circuitry to drive an external P-FET to isolate the output side from the input side. This application report details the start-up behavior of the TPS61178x device. It also characterizes the
start-up timing and proposes a method to reduce the start-up inrush current. The proposed method is
confirmed by bench test measurements.