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 voltage regulator.
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