KA2803B Fairchild Semiconductor, KA2803B Datasheet - Page 2

• Manufacturer Part Number: KA2803B
• Description: IC EARTH LEAKAGE DETECTOR 8-DIP
• Manufacturer: Fairchild Semiconductor

Specifications of KA2803B

• Applications: Earth Leakage Detector
• Current - Supply: 400µA
• Voltage - Supply: 12 V ~ 20 V
• Operating Temperature: -25°C ~ 80°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

© 2000 Fairchild Semiconductor Corporation
KA2803B • Rev. 1.0.6
Block Diagram
Application Circuit
Application Information
(Refer to full-wave application circuit in Figure 2)
Figure 2 shows the KA2803B connected in a typical
leakage current detector system. The power is applied
to the V
The resistor R
8 voltage is at least 12V. The value of C
recommended above 1µF.
If the leakage current is at the load, it is detected by the
zero current transformer (ZCT). The output voltage
signal of ZCT is amplified by the differential amplifier of
the KA2803B internal circuit and appears as a half-
cycle sine wave signal referred to input signal at the
output of the amplifier. The amplifier closed-loop gain is
fixed about 1000 times with internal feedback resistor to
compensate
variations. The resistor R
the breaker satisfies the required sensing current. The
protection resistor R
current is injected at the breaker; this resistor should be
Figure 2.
CC
terminal (Pin 8) directly from the power line.
S
for
and capacitor C
Full-Wave Application Circuit
zero
P
is not usually used when high
L
current
should be selected so that
S
are chosen so that Pin
transformer
Figure 1. Block Diagram
(ZCT)
S
is
2
used to protect the earth leakage detector IC
(KA2803B). The range of R
Ω to several kΩ.
Capacitor C
value of C
canceller capacitance, but it is not usually used.
When high noise is present, a 0.047µF capacitor may
be connected between Pins 6 and 7. The amplified
signal finally appears at the Pin 7 with pulse signal
through the internal latch circuit of the KA2803B. This
signal drives the gate of the external SCR, which
energizes the trip coil, which opens the circuit breaker.
The trip time of the breaker is determined by capacitor
C
be selected under 1µF to satisfy the required trip time.
The full-wave bridge supplies power to the KA2803B
during both the positive and negative half cycles of the
line voltage. This allows the hot and neutral lines to be
interchanged.
3
and the mechanism breaker. This capacitor should
Figure 3.
1
1
is 0.047µF. Capacitor C2 is also a noise
is for the noise canceller and a standard
Half-Wave Application Circuit
P
is from several hundred
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