Systems, methods, and devices related to a converter of a wireless power transmitter are disclosed. A controller for a wireless power transmitter is configured to sample an output voltage potential to produce a digital output voltage potential, determine an error between an output reference voltage potential and the digital output voltage potential, filter the error to determine a filtered error, and apply an adaptive gain to the filtered error to determine a duty cycle control signal. The adaptive gain is determined responsive to a converter input voltage potential of the converter of the wireless power transmitter. The controller is further configured to determine a controller output including buck pulse width modulation (PWM) signals and boost PWM signals based on the duty cycle control signal, the controller output configured to control the converter of the wireless power transmitter.