SLVSCM2D October 2014 – December 2019 TPS1H100-Q1
A high-accuracy current limit allows higher reliability, which protects the power supply during short circuit or power up. Also, it can save system costs by reducing PCB traces, connector size, and the capacity of the preceding power stage.
Current limit offers protection from overstressing to the load and integrated power FET. Current limit holds the current at the set value, and pulls up the CS pin to VCS,h as a diagnostic report. The two current-limit thresholds are:
Both the internal current limit (Ilim,nom) and external programmable current limit are always active when VVS is powered and IN is high. The lower one (of Ilim,nom and the external programmable current limit) is applied as the actual current limit.
Note that if a GND network is used (which leads to the level shift between the device GND and board GND), the CL pin must be connected with device GND. Calculate RCL with Equation 2.
For better protection from a hard short-to-GND condition (when VS and input are high and a short to GND happens suddenly), an open-loop fast-response behavior is set to turn off the channel, before the current-limit closed loop is set up. The open-loop response time is around 1 µs. With this fast response, the device can achieve better inrush-suppression performance.