DISCRETE LOWEST CURRENT MEASUREMENT

摘要

The invention relates to a method and a circuit for carrying out discrete lowest current measuring. The invention provides that, during a measuring cycle, measuring current of a measuring current source is measured in a switchable integrator capacitor after a defined measuring cycle duration by using an output voltage, which represents the measuring current, of an integrator operation amplifier. A reset integration is carried out in a subsequent reset cycle by the switching of a reset current, which flows through the integrator capacitor, effected a reset semiconductor switch. The aim of the invention is to realize methods and circuits for discretely measuring currents 0.1* 10<-15> A whereby, in doing this, it is indispensable to compensate for interferences such as interfering charge influences of semiconductor switches, offset voltage and offset voltage drift. To this end, circuits of the utilized reset semiconductor switch and compensation circuit are designed in such a manner that they make it possible to measure the lowest currents in the targeted measuring range 0.1* 10<-15> A for carrying out the discrete lowest current measurement with the aid of the applied methods for compensating offset voltage and offset voltage drift as well as for compensating for the interfering charge effects in the switching over processes of the reset semiconductor switch.