1 Introduction

Several power sources have limited output current capability based on circuit characteristics or electrical standards. For instance, the maximum output current of Universal Serial Bus (USB) 2.0 port is 0.5 A. For Peripheral Component Interconnect Express (PCIe) card and USB Type-C® port the current is limited to 3 A. Also, Li-Ion or alkaline batteries have limited discharge current capability due to the internal resistance (ESR). When overloading these batteries, their capacity and the lifetime can be significantly reduced. A DC-DC converter with average input current limit function can help to avoid overloading such power sources.

Furthermore, switching power converters can typically generate inrush current when turning on. High inrush current can overload the power source. This process can trigger the UVLO and prevent the converter from a reliable startup. The conditions can be even worse while charging a large storage bulk output capacitor. There is also another function of input current limit, that is, control inrush current and provide controlled current to charge large capacitors.

TPS61376 with its integrated features can control and limit the input current during start up and steady state condition.