INTEGRATED CIRCUIT FOR LEAKAGE CURRENT DETECTION AND EARTH LEAKAGE CIRCUIT BREAKER HAVING THE SAME

摘要

According to the present invention, a semiconductor integrated circuit for leakage current detection outputs a blocking signal for blocking supply of power supplied to an electric line from a power supply when a leakage current is caused by a short circuit, and comprises a leakage current processing unit and an output unit to operate in accordance with a trip signal outputted by the leakage current processing unit to output a blocking signal. The leakage current processing unit includes: a power voltage zero detector to output a power voltage pulse signal whenever a power voltage becomes 0V; a counter to count a predetermined number (N) when the power voltage pulse signal is inputted; an input induction voltage zero detector to output a leakage current pulse signal whenever an input induction voltage becomes 0V; a counter latch to latch a count number counted by the counter to output a latched count number when the leakage current pulse signal is inputted; an output induction voltage setting unit to calculate an output induction voltage from the latched count number, the input induction voltage, and the predetermined number (N); and a comparator to compare the output induction voltage with a predetermined trip level, and output a trip signal if the level of the output induction voltage is larger than the trip level.