Ground fault circuit interrupter (gfci) with limit detection and adaptive sample accumulation window

Abstract

An integrated circuit includes front-end circuitry coupled to a current sensor, which is coupled to alternating current (AC) mains, and to convert a leakage current to a converted voltage. An analog-to-digital converter (ADC), coupled to the front-end circuitry, converts the converted voltage to a digital signal. The ADC includes limit detection circuitry to detect the digital signal indicating the converted voltage is lower than a low threshold limit or higher than a high threshold limit and output a limit interrupt in response to the detection. Control logic is coupled to an output of the ADC and to process, in response to receiving the limit interrupt, the digital signal to determine a root mean square (RMS) value, and output a trip signal to trip logic to cause a disconnect of a current supplied to a load by the AC mains in response to the RMS value satisfying a threshold trip value.