SLVS892F December 2008 – April 2019 TPS61175
The over-current limit for the integrated power FET limits the maximum input current and thus the maximum input power for a given input voltage. Maximum output power is less than maximum input power due to power conversion losses. Therefore, the current limit setting, input voltage, output voltage and efficiency can all change the maximum current output (IOUT(MAX)). The current limit clamps the peak inductor current, therefore the ripple has to be subtracted to derive maximum DC current.
For instance, when VIN = 12 V is boosted to VOUT = 24 V, the inductor is 10 µH, the Schottky forward voltage is 0.4 V, and the switching frequency is 1.2 MHz; then the maximum output current is 1.2 A in typical condition, assuming 90% efficiency and a %RPL = 20%.