A current integrator is described for generating an output voltage (Vo) in response to an input current (Ii) to be integrated, the input current being applied to an integration capacitor (12) via a current-current converter (16). This enables one end (14) of the integration capacitor to be connected to a fixed voltage and to be implemented by means of a MOS transistor which occupies a comparatively small area. A further area reduction is possible by making the current gain (K) of the current-current converter (16) smaller than 1.
