Hysteresis mode or PWM operation mode Switching PS?

Hi I’m starting on selecting a power supply to my project, I want to know what is the difference of each mode

Are you talking about control Methods? Usually You hear about Voltage Mode (PWM) Current Mode, and Hysteresis or Ripple Mode. Are there certain power supplies that you are looking at, or certain specifications or features that you need?

If you are just researching control methods Rohm Semiconductor has a post from back in 2015

-Robert