Title:
SEMICONDUCTOR INTEGRATED CIRCUIT FOR EARTH LEAKAGE CIRCUIT BREAKER
Document Type and Number:
Japanese Patent JP2017093237
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit for low cost earth leakage circuit breaker corresponding to detection of a leakage current of pulsating waveform subjected to half-wave rectification.SOLUTION: The integration circuit 7 of a semiconductor integrated circuit for earth leakage circuit breaker includes a clock synthesis circuit 11 outputting a high frequency first clock signal for addition operation and a low frequency second clock signal for subtraction operation, based on a signal (leakage signal) S2 indicating whether or not the absolute value of a detection signal, detected by a zero-phase current transformer, exceeds a constant voltage value. An up-down counter 12 adds by the first clock signal when the absolute value of a detection signal exceeds the constant voltage value, otherwise subtracts by the second clock signal. Since the subtraction ratio lowers compared with addition, leakage determination even of a leakage current of pulsating waveform is possible, because subtraction of integrated value is suppressed.SELECTED DRAWING: Figure 1
Inventors:
NAKAGOME KENJI
Application Number:
JP2015223703A
Publication Date:
May 25, 2017
Filing Date:
November 16, 2015
Export Citation:
Assignee:
FUJI ELECTRIC CO LTD
International Classes:
H02H3/347; H01H83/02
Attorney, Agent or Firm:
Takeshi Hattori