The TPS6305x devices have an internal user programmable current limit that monitors the input current during start-up. This prevents high inrush current protecting the device and the application. During start-up the input current does not exceed the current limit that is set by ILIM0 pin and ILIM1 pin. Depending on the logic level applied at these two pins, switching between four different current limit-levels is possible. The variation of those values over input voltage and temperature is shown in Figure 1 through Figure 2. Adjusting the soft-start time further using the soft-start capacitor is possible.
ILIM0 and ILIM1 set the current limit as listed in Table 2.
|ILIM1||ILIM0||CURRENT LIMIT SET (WCSP)||CURRENT LIMIT SET (HotRod)|
|Low||Low||0.4 × IIN_MAX||Not Available|
|Low||High||0.5 × IIN_MAX||Not Available|
|High||Low||0.65 × IIN_MAX||0.65 × IIN_MAX|
The ILIM0, ILIM1 pins can be changed during operation.
Given the curves provided in Figure 1 through Figure 2, calculating the output current in the different condition in boost mode is possible using Equation 1 and Equation 2 and in buck mode using Equation 3 and Equation 4.