MITSUBISHI <CONTROL / DRIVER IC>
M54123L
EARTH LEAKAGE CURRENT DETECTOR
DESCRIPTION
The M54123L is a semiconductor integrated circuit with amplifier
for a high-speed earth leakage circuit breaker.
PIN CONFIGURATION (TOP VIEW)
FEATURES
q
Suitable for JIS C 8371
q
Good temperature characteristics of input sensitivity current
q
High input sensitivity (V
T
= 6.1mV Typ.)
q
Low external component count
q
High noise and surge-proof
q
Low power dissipation (P
d
= 5mW Typ.) and may be used both
as 100V and 200V.
q
High mounting density by SIL package with 8 pins
q
Wide temperature range (Ta = -20 – +80°C)
Reference voltage
Input
V
R
→
IN
→
GND
1
2
3
4
5
6
7
8
REG
LATCH
AMP
Differential amplifier output
Latch input
Terminal for noise absorption
Output
O
D
←
S
C
→
N
R
→
O
S
←
V
S
APPLICATION
High speed earth leakage circuit breaker
FUNCTION
The M54123L circuit for the amplifying parts of earth leakage
circuit breaker consists of differential amplifier, latch circuit and
voltage regulator. It is connected to the secondary side of the zero-
current transformer (ZCT) which detects leakage current in the
both input of the differential amplifier. Signals amplified by
differential amplifier are integrated by an external capacitor, and
connects to the input terminal of latch circuit with output suitable for
the characteristics of high-speed earth leakage circuit breaker.
Latch circuit keeps low in the output till the input voltage reaches
the fixed level, and output becomes high when the leakage current
more than fixed flows. It drives a thyristor connected to the output
terminal of latch circuit.
Outline 8P5
BLOCK DIAGRAM
V
S
8
Reference voltage generator
Latch circuit
AMP
7
O
S
output
GND 3
1
V
R
Reference
voltage
2
IN
Input
4
O
D
Differential
amplifier
output
5
S
C
Latch
input
6
N
R
Terminal for noise
absorption
BIAS
MITSUBISHI [ MITSUBISHI ELECTRIC SEMICONDUCTOR ]
