Patent ID: 11879915
Assignee: SIEMENS AKTIENGESELLSCHAFT
Field: Measurement (Instruments)
Classification: CPC G | IPC G  H

Claim 0:
1. A method for evaluating an input voltage of a switched-mode power supply, the input voltage having a predetermined polarity, the method comprising:
sampling the input voltage at a predetermined sampling rate to create a digitized input voltage;
filtering the digitized input voltage supplied as an input signal to a filter, such that an output signal from the filter lags the input signal of the filter;
comparing, by a comparator, the input signal of the filter with the output signal from the filter; and
evaluating, by a sequence control system, comparison results delivered by the comparator;
wherein, during a respective evaluation period which is started by resetting a counter, comparison results delivered by the comparator are evaluated by the sequence control system until, subsequent to a first change in state of a comparison result, a further change in state of a comparison result is identified; and
wherein a respective evaluation period is then terminated and, utilizing a present count value of the counter, at least one of a period duration and a frequency of an AC voltage component of the input voltage are determined.