A capacitive power supply device for a control device of an electrical switching apparatus, including a power supply module that has two input terminals and a power supply voltage between the two terminals, and suitable for supplying a power supply current to a control member suitable for controlling the electrical switching apparatus when the power supply voltage is below a predetermined actuation threshold, the power supply module including a first capacitor connected at the input of voltage rectifying means, the control member being connected at the output of a rectifying block, wherein a second capacitor and a first switch, suitable for connecting the second capacitor based on a comparison of the power supply voltage to a capacitor switching threshold value.