A capacitive sensor comprising: at least one capacitive element (100, 102); a switched-capacitor readout circuit part configured to detect at least one signal capacitance that results from motions of the capacitive element (100, 102); a first switch arrangement configured to electrically couple the switched-capacitor readout circuit part to the capacitive element (100, 102) for a front end readout period (Φ read), and to electrically decouple the switched-capacitor readout circuit part from the capacitive element for a front end reset period (Φ reset); a self-test controller configured to enable and disable a self-test of the capacitive sensor; an actuation circuit part configured to generate a self-test bias voltage for electrostatic deflection of the capacitive element (100, 102); a second switch arrangement configured to electrically couple the self-test bias voltage of the actuation circuit part to the capacitive element (100, 102) during a first period, wherein the first period is synchronized to the front end reset period (Φ reset) and is configured to occur when the self-test of the capacitive sensor is enabled by the self-test controller, and to electrically decouple the actuation circuit part from the capacitive element (100, 102) in times other than the first period; wherein the second switch arrangement is configured to generate a self-test control signal (ST(Φ reset)), a first state of the self-test control signal relating to the first period, and the second state of the self-test control signal relating to the times other than the first period; characterized in that: the actuation circuit part includes a high-voltage charge pump and a high-voltage charge pump control circuitry (602, 604, 606) configured to enable and disable generation of the self-test bias voltage by the high-voltage charge pump; and the high-voltage charge pump control circuitry (602, 604, 606) is responsive to the self-test control signal (ST(Φ reset)) such that enabling and disabling generation of the self-test bias voltage by the high-voltage charge pump depends on the self-test control signal. at least one capacitive element (100, 102); a switched-capacitor readout circuit part configured to detect at least one signal capacitance that results from motions of the capacitive element (100, 102); a first switch arrangement configured to electrically couple the switched-capacitor readout circuit part to the capacitive element (100, 102) for a front end readout period (Φ read), and to electrically decouple the switched-capacitor readout circuit part from the capacitive element for a front end reset period (Φ reset); a self-test controller configured to enable and disable a self-test of the capacitive sensor; an actuation circuit part configured to generate a self-test bias voltage for electrostatic deflection of the capacitive element (100, 102); a second switch arrangement configured to electrically couple the self-test bias voltage of the actuation circuit part to the capacitive element (100, 102) during a first period, wherein the first period is synchronized to the front end reset period (Φ reset) and is configured to occur when the self-test of the capacitive sensor is enabled by the self-test controller, and to electrically decouple the actuation circuit part from the capacitive element (100, 102) in times other than the first period; wherein the second switch arrangement is configured to generate a self-test control signal (ST(Φ reset)), a first state of the self-test control signal relating to the first period, and the second state of the self-test control signal relating to the times other than the first period; characterized in that: the actuation circuit part includes a high-voltage charge pump and a high-voltage charge pump control circuitry (602, 604, 606) configured to enable and disable generation of the self-test bias voltage by the high-voltage charge pump; and the high-voltage charge pump control circuitry (602, 604, 606) is responsive to the self-test control signal (ST(Φ reset)) such that enabling and disabling generation of the self-test bias voltage by the high-voltage charge pump depends on the self-test control signal. the actuation circuit part includes a high-voltage charge pump and a high-voltage charge pump control circuitry (602, 604, 606) configured to enable and disable generation of the self-test bias voltage by the high-voltage charge pump; and the high-voltage charge pump control circuitry (602, 604, 606) is responsive to the self-test control signal (ST(Φ reset)) such that enabling and disabling generation of the self-test bias voltage by the high-voltage charge pump depends on the self-test control signal.