A control system with a voltage-to-time converter for combined buck-boost converter using a single inductor. The system includes a voltage-to-time converter circuit having first and second inputs coupled to receive first and second voltage signals, respectively. The voltage-to- time converter includes a comparator configured to compare the first voltage signal and the second voltage signal and to generate a comparator output signal at a first level if the first voltage is greater than the second voltage and at a second level if the second voltage is greater than the first voltage. The voltage-to-time converter further includes an output circuit configured to generate first and second output signals based on the comparator output signal. The output circuit is configured to provide a selected one of the first or second output signals at the first level for a duration dependent on a difference between respective voltages of the first and second voltage signals.