Circuit for detecting a level or a variation of an input direct voltage

摘要

A circuit for detecting a level of an input direct voltage comprises a comparator for comparing the input direct voltage with a reference signal, which by means of an integrator is derived from pulses whose charge quantity is variable in dependence on a comparator direct voltage. The reference voltage has a d.c. component and an a.c. component. The comparator supplies comparator pulses of a given pulse duration when the d.c. component of the reference voltage is substantially equal to the input direct voltage. The level of the input direct voltage is determined from the charge quantity of the pulses and from the pulse duration of the comparator pulses.