A direct current (DC) voltage converter configured to transition between operation modes is disclosed. A voltage selection circuitry is provided in a DC voltage conversion circuit to control a buck-boost converter that generates a DC output voltage. As opposed to conventional methods of switching the buck-boost converter between a buck mode and a boost mode based on a single switching threshold, the voltage selection circuitry is configured to switch the buck-boost converter between the buck mode and the boost mode based on multiple voltage thresholds. Each of the multiple voltage thresholds defines a respective range for the DC output voltage. By controlling the buck-boost converter based on multiple voltage thresholds, it is possible to provide a smoother transition between the buck mode and the boost mode, thus reducing voltage errors in the DC output voltage and improving reliability of the DC voltage conversion circuit.