Switched capacitor voltage converter for a rechargeable battery in a hearing aid

The disclosure presents a method of operating a switched capacitor voltage converter and a switched capacitor voltage converter, where the switched capacitor voltage converter comprises a power source, a bucket capacitance, an output capacitance with output capacitance terminals to be connected to a load and switches. The power source provides an input voltage and the output capacitance provides an output voltage over the output capacitance terminals. The output voltage is different from the input voltage, i.e higher or lower or of opposite polarity. The switches are configured to provide at least two phases, a bucket capacitance charging phase and a bucket capacitance discharging phase. In case of a voltage up-converter in the bucket capacitance charging phase the bucket capacitance is connected to the power source for charging the bucket capacitance while the bucket capacitance is not connected to the output capacitance. In a voltage down-converter in the bucket capacitance charging phase the bucket capacitance and the output capacitance are connected in series with the power source. In a voltage up-converter in the bucket capacitance discharging phase the bucket capacitance is connected in series with the power source for charging the output capacitance. In a voltage down-converter in the bucket capacitance discharging phase the bucket capacitance and the output capacitance are connected in parallel with each other while being disconnected from the power source. Further, a detection circuit is provided that is configured to monitor the output voltage over the output capacitance terminals and to cause switching of at least one of said switches so as to interrupt charging of the output capacitance when output voltage exceeds a predefined reference voltage.