A voltage regulator system includes a switch system including a power switch to conduct an output current through an inductor based on an input voltage and a switching signal to generate an output voltage at a load. A feedback system generates a PWM signal based on the output voltage and based on a variable reference voltage. A gate driver system generates the switching signal based on the PWM signal. The gate driver system controls the switch system to increase the output voltage at output voltage slopes in each of startup stages during startup of the voltage regulator system. A sampling system samples the output current and the output voltage during the startup of the voltage regulator system to measure each slope of the output voltage slopes at each of the respective startup stages during the startup of the voltage regulator system.