The invention relates to a charge amplifier circuit for converting positive and negative charge signals Q that are output by a piezoelectric measuring element into a digital signal D that is proportional to the present measured value at the measuring element. The circuit comprises a charge amplifier V1 having a charge input and a voltage output for converting detected charge Q into voltage U2, wherein a compensation circuit K comprising two outputs is connected downstream of the voltage output of the charge amplifier V1 and wherein the first output is connected to the charge input of the charge amplifier V1 and the second output is connected to a counter Z having two inputs Z+ and Z-. On the one hand, the compensation circuit K can produce a compensation charge Qk+ or Qk- that is proportional to the voltage U2 and that can be sent to the charge input of the charge amplifier V1 by means of the first output in order to compensate the input signal Q, and on the other hand, the compensation circuit can produce a number of pulses P+, P1 that is proportional to the magnitude of each compensation charge Qk+ or Qk- produced. Said pulses can be sent to an input Z-, Z+ of the counter Z opposite the sign of the particular compensation charge Qk+ or Qk- by means of the second output, wherein the desired digital signal D, which is proportional to the sum of the charge quanta input beforehand, is available at the output of the counter Z. The invention further relates to a method that is performed on such a circuit.