HCPL-7860-300E Datasheet, PDF (12/18 Pages) AVAGO TECHNOLOGIES LIMITED – Optically Isolated Sigma-Delta (S-D) Modulator

100
90
80
70
60
50
40
30
20
10
0
1
2
3
4
5
CONVERSION MODE #
Figure 13. Signal Delay vs. Conversion Mode.
V _IN+ (200 mV/DIV.)
OVR1 (200 mV/DIV.)
THR1
(2 V/DIV.)
2 μs/DIV.
Figure 14. Over-Range and Threshold Detect Times.
Application Information
100
90
Digital Current Sensing
80
As shown in Figure 16, using the Isolated 2-chip A/D con-
70
verter to sense current can be as simple as connecting a
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current-sensing resistor, or shunt, to the input and reading
50
output data through the 3-wire serial output interface.
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By choosing the appropriate shunt resistance, any range
30
of current can be monitored, from less than 1 A to more
20
than 100 A.
10
0
Even better performance can be achieved by fully utilizing
1
2
3
4
CONVERSION MODE #
5
the more advanced features of the Isolated A/D converter,
such as the pre-trigger circuit, which can reduce conver- ^{Figure 15. Signal Bandwidth vs. Conversion Mode.}
sion time to less than 1 Ps, 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 measure-
ments, 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-7860/
HCPL-786J
Figure 16. Typical Application Circuit.
12
C2
0.1 μF
CCLK
CLAT
CDAT
MCLK1
MDAT1
MCLK2
MDAT2
GND
V _DD
CHAN
SCLK
SDAT
CS
THR1
OVR1
RESET
HCPL-0872
3-WIRE
SERIAL
INTERFACE
+ _C3
10 μF