ae in the present exemplary embodiment the evaluation device ae contains a simple up down counter adc and a downstream connected four bit count indicator za the count of the up down counter adc is supplied to the count indicator za whose output provides for each bit a respective enable signal en 1 en 4 which can be supplied to the respective associated controllable switching device se 1 se 4 on the input side each controllable switching device se 1 se 4 is connected to a first supply line 4 which has a supply potential vdd applied to it and to a second supply line 5 which has the reference ground potential gnd applied to it on the output side each controllable switching device se 1 se 4 is connected to the other capacitor connection of the respective pump capacitor c 1 c 4 associated with it as already mentioned a controllable switch se 1 u2032 se 4 u2032 within each of the controllable switching devices se 1 se 4 can be used to apply either the supply potential vdd or the reference ground potential gnd reciprocally to the aforementioned capacitor connection on the basis of the enable signal en 1 en 4 the controllable switches se 1 u2032 se 4 u2032 are likewise controlled by a clock pulse which can be derived from the oscillator clock 21 the signal en will either force the switching devices se 1 se 4 to apply ground or it will allow the switching devices se 1 se 4 to toggle between vdd and gnd responsive to the u201c clock pulse u201d it is found to be particularly advantageous if the respective switching devices se 1 se 4 with the respective switches.