A DC-to-DC converter, comprising: - input terminals (702, 708) configured for application of a DC input voltage from an external voltage source to the DC-to-DC converter; - output terminals (714, 716) configured for providing a DC output voltage from the DC-to-DC converter to an external load unit; - a reconfigurable capacitor unit provided with a substrate and comprising a plurality of capacitive structures each comprising a first and a second electrically conductive capacitor-electrode layer and an intermediate dielectric layer; - a switching unit that comprises a plurality of switching elements (S1 to S4) electrically interconnected between different capacitive structures, wherein the individual switching elements are configured to electrically connect, in a first switching state, two respective capacitor-electrode layers with each other, and to electrically disconnect, in a second switching state, the same two respective capacitor-electrode layers from each other, the switching elements having a control input terminal and being configured to assume either the first or the second switching state in dependence on a switch-control signal applied to the control input terminal, wherein the switching unit is configured to form a first multi-capacitor configuration with at least two capacitors (C1, C2) connected between the input terminals and a second multi-capacitor configuration that comprises at least one output capacitor internally connected between the output terminals; and - a control unit, which is connected with the switching unit and which is configured to generate and provide to the switching unit respective control signals for forming a respective one of a plurality of multi-capacitor configurations using the capacitive structures, wherein the control unit is configured to generate and provide control signals to the switching unit for periodically switching between the first and second multi-capacitor configurations with a switching frequency and characterised in that the control unit is configured to adjust the switching frequency to a switching-frequency value that minimizes an output impedance of the DC-to-DC converter and at the same time represents a minimum switching-frequency value in a set of switching-frequency values (fs), which minimize the output impedance of the DC-to-DC converter. - input terminals (702, 708) configured for application of a DC input voltage from an external voltage source to the DC-to-DC converter; - output terminals (714, 716) configured for providing a DC output voltage from the DC-to-DC converter to an external load unit; - a reconfigurable capacitor unit provided with a substrate and comprising a plurality of capacitive structures each comprising a first and a second electrically conductive capacitor-electrode layer and an intermediate dielectric layer; - a switching unit that comprises a plurality of switching elements (S1 to S4) electrically interconnected between different capacitive structures, wherein the individual switching elements are configured to electrically connect, in a first switching state, two respective capacitor-electrode layers with each other, and to electrically disconnect, in a second switching state, the same two respective capacitor-electrode layers from each other, the switching elements having a control input terminal and being configured to assume either the first or the second switching state in dependence on a switch-control signal applied to the control input terminal, wherein the switching unit is configured to form a first multi-capacitor configuration with at least two capacitors (C1, C2) connected between the input terminals and a second multi-capacitor configuration that comprises at least one output capacitor internally connected between the output terminals; and - a control unit, which is connected with the switching unit and which is configured to generate and provide to the switching unit respective control signals for forming a respective one of a plurality of multi-capacitor configurations using the capacitive structures, wherein the control unit is configured to generate and provide control signals to the switching unit for periodically switching between the first and second multi-capacitor configurations with a switching frequency and characterised in that the control unit is configured to adjust the switching frequency to a switching-frequency value that minimizes an output impedance of the DC-to-DC converter and at the same time represents a minimum switching-frequency value in a set of switching-frequency values (fs), which minimize the output impedance of the DC-to-DC converter.