Avago Technologies ACPL-224-500E - Manual (Page 60)

AV02-4387EN 57 Avago Technologies
Description
The HCPL-4562 Linear Optocoupler
is used in a servo circuit to sense the
rectified dc power supply voltage of
a power inverter. The series resistor
R
1
limits the current that drives the
input LED of optocoupler U1. The
forward current through the LED
of the HCPL-4562 optocoupler is
proportional to the dc high voltage
power supply rail.
When the circuit is balanced with
the potentiometer R3, the output
voltage V
O
is proportional to the
high voltage dc power supply as
shown by the equation:
V
O
/ V
I
= R
2
/ R
1
Performance of Circuit
• 122 dB isolation mode rejec tion
ratio
• 0.25% nonlinearity
• ±0.3%/°C gain variation tempera-
ture coefficient
Benefits
• No isolated 5 V input power sup-
ply is required for optocoupler U1
• Simple circuit
Alternative Avago Parts
1) HCPL-7800A: 1% part-to-part
gain tolerance
2) HCPL-7800: 3% part-to-part gain
tolerance
Motor Control Applications
Isolated Inverter Rail Voltage Sensing using a Linear Optocoupler
HV+
HCPL-4562
HV–
R
1
V
I
2
3
8
5
6
U1
HCPL-4562
R
2
V
O
2
3
8
5
6
U3
+
–
V
CC
ISOLATION
BARRIER
U2
V
O
R
2
V
I
R
1
R
4
R
5
R
3
C
1