HCPL-7560 Datasheet, PDF (12/18 Pages) Agilent(Hewlett-Packard) – Optically Isolated Sigma-Delta Modulator

Applications Information
Digital Current Sensing
As shown in Figure 16, using
the Isolated 2-chip A/D
converter to sense current can
be as simple as connecting a
current-sensing resistor, or
shunt, to the input and
reading output data through
the 3-wire serial output
interface. By choosing the
appropriate shunt resistance,
any range of current can be
monitored, from less than 1 A
to more than 100 A.
Even better performance can
be achieved by fully utilizing
the more advanced features of
the Isolated A/D converter,
such as the pre-trigger circuit,
which can reduce conversion
time to less than 1 ìs, the fast
over-range detector for quickly
detecting short circuits,
different conversion modes
giving various resolution/speed
trade-offs, offset calibration
mode to eliminate initial offset
from measurements, and an
adjustable threshold detector
for detecting non-short circuit
overload conditions.
NON-ISOLATED
+5V
INPUT
CURRENT
+
R _SHUNT
0.02
ISOLATED
+5V
C1
0.1 µF
V _DD1
V _IN+
V _IN-
GND1
V _DD2
MCLK
MDAT
GND2
HCPL-7560
Figure 16. Typical Application Circuit.
C2
0.1 µF
CCLK
CLAT
CDAT
MCLK1
MDAT1
MCLK2
MDAT2
GND
V _DD
CHAN
SCLK
SDAT
CS
THR1
OVR1
RESET
HCPL-0872
+
C3
10 µF
3-WIRE
SERIAL
INTERFACE
12