Current Mode Buck Converter. Switch current limiting ensures minimal overshoot. A diode clamp ensures the error voltage is kept under control. Keeping the error voltage close to the ramp voltage means instant reaction to approaching the set voltage and hence minimal overshoot. I have used a 0.1V reference, but a 2.5V voltage reference can be used and adjustments can be made to the current sense circuit (eg adding 2.5V to the output of the current sense amp to offset the 2.5V added to the error amp output). This results in a lower rate of rise of output voltage, an added soft start.
