The value of R1, R2, C4, and C5 should be chosen in order to keep at least 12V in Vs.
Please connect C4 (>1μF) and C2 (<1μF). ZCT and load resistance RL of ZCT are connected between input pin 1 and 2. Protective resistance (RP=100Ω) must be insurted. RL and amplifier’s output (in Pin 4) regulates sensitivity current External capacitor C1 between pin 4 and GND is used for noise removal. Please connect a varistor or a diode (2 pcs.) to ZCT in parallel, because of when large current is grounded in the primary side (AC line) of ZCT, the following situation can be abandoned: The wave form in the secondary side of ZCT is distorted and some signals do not appear in the output of amplifier. Please connect capacitor (about 0.047μF) between pin 6 and pin 7. Capacitor C6 between pin 1 and GND is about 0.047μF for removing noise. M54123L
EARTH LEAKAGE CURRENT DETECTOR
The UTC M54123L is a semiconductor integrated circuit with
amplifier for a high-speed earth leakage circuit breaker.
For the amplifying parts of earth leakage circuit breaker, the
UTC M54123L consists of differential amplifier, latch circuit and
In normal operating, the UTC M54123L should be connected
to the secondary side of the ZCT (zero current transformers). Here
the ZCT detects leakage current different amplifiers’ both input.
Then the signals which have been amplified are integrated by
an external capacitor. The integrated signal connects to the input
terminal of latch circuit whose output is suitable for the
characteristics of high- speed earth leakage circuit breaker.
Until the input voltage reaches the fixed level, latch circuit
doesn’t become high. Then drives a thyristor which is connected to
latch circuit’s output terminal.
* With good input sensitivity current temperature characteristics
* High input sensitivity :VT=6.1mV (Typ.)
* Only need low external component count
* High noise and surge-proof
* Low power dissipation :PD=5mW (Typ.)
* May be used both as 100V and 200V.
* Wide temperature range : from -20 °C to +80°C