M54124L Datasheet, PDF (1/10 Pages) Mitsubishi Electric Semiconductor – EARTH LEAKAGE CURRENT DETECTOR

M54124L
Earth Leakage Current Detector
REJ03F0031-0100Z
Rev.1.0
Sep.16.2003
Description
The M54124L is a semiconductor integrated circuit having amplifier functions for high-speed earth leakage breakers.
Features
• Satisfies JIS C 8371 standards
• Good temperature characteristic of input sense current
• High input sensitivity (V_T=6.5 mV)
• Fewer external components, for greater economy
• Good stability with respect to noise, surges
• Can be used at both 100 V and 200 V with low power consumption (P_d=5 mW)
• 8-pin SIP for high mounting density
• Broad operating temperature range (Ta=-20 to 80°C)
Applications
• High-speed earth leakage breaker
Summary of Functions
This integrated circuit is used in the amplification unit of earth leakage breakers, and consists of a differential amplifier,
one-shot circuit, output circuit, and constant-voltage circuit. The secondary side of a zero-phase current transformer
(ZCT) which detects leakage currents is connected to both inputs of the differential amplifier. The signal amplified by
the differential amplifier is integrated by an external capacitor, and after obtaining a time delay satisfying the
characteristics of a high-speed earth leakage breaker as stipulated in JIS C 8371, is connected to the input of the one-
shot circuit. The one-shot circuit holds its output at "L" level until the input voltage reaches a prescribed level, and
when a leakage current above the prescribed level flows, generates an "H" one-shot pulse at the output, to drive a
thyristor connected to the output.
Rev.1.0, Sep.16.2003, page 1 of 9