TPS1211-Q1: I use TPS12111LQDGXRQ1 in my design, I want to know whether the IC support MOS soft start？If support，how much sort start time？

Hi Ling,

TPS1211-Q1 can do soft-start by adding RC network at the GATE (PU pin) as shown in Figure 8-6 in the data sheet. You can use large RC value to set long startup time while charging large Cout with lower inrush current.

Please use design calculator for calculating RC values.

BR,

Rakesh

Hi Ling,

7317.TPS1211-Q1_Design_Calculator.zip

BR,

Rakesh

The tool only gives the value of C1 to set the target inrush current.

You can calculate (soft start time Tcharge) manually by using equations 2 and 3 in the data sheet

BR,

Rakesh

as it is RC network with exponential rise-time, we have approximated with linear curve for 1 time constant. https://en.wikipedia.org/wiki/RC_time_constant