Supply AC voltage detection circuit for electrical device evaluates delay time between fixed point on supply voltage in terms of time or voltage and logic level change for constant threshold

摘要

The circuit has a logic level stage to which the AC voltage (UN) is applied and tat has an associated constant threshold voltage, whereby a logic level change occurs when the voltage exceeds or falls below the threshold. A delay time between a fixed point on the supply voltage in terms of time or voltage and the level change depends on the current voltage magnitude