Application Information
the input of the HCPL-7510
through an RC anti-aliasing
filter (R2 and C2). Although
the application circuit is
relatively simple, a few
recommendations should be
followed to ensure optimal
performance.
Otherwise, some sort of simple
isolated supply can be used,
such as a line powered
transformer or a high-
frequency DC-DC converter.
Power Supplies and Bypassing
The recommended supply
connections are shown in
Figure 16. A floating power
supply (which in many
An inexpensive 78L05 three-
terminal regulator can also be
used to reduce the floating
supply voltage to 5 V. To help
attenuate high- frequency
power supply noise or ripple,
a resistor or inductor can be
used in series with the input
of the regulator to form a
low-pass filter with the
applications could be the same
supply that is used to drive
the high-side power transistor)
is regulated to 5 V using a
simple zener diode (D1); the
value of resistor R4 should be
chosen to supply sufficient
current from the existing
floating supply. The voltage
from the current sensing
The power supply for the
HCPL-7510 is most often
obtained from the same supply
used to power the power
transistor gate drive circuit. If
a dedicated supply is required,
in many cases it is possible to
add an additional winding on
an existing transformer.
regulator’s input bypass
capacitor.
resistor (Rsense) is applied to
HV+
+
FLOATING
POSITIVE
SUPPLY
GATE DRIVE
CIRCUIT
-
R4
C1
0.1 µF
D1
5.1 V
VDD1
VIN+
VIN-
1
2
3
R2
39 Ω
C2
0.01 µF
HCPL-7510
MOTOR
R1
+
-
4 GND1
RSENSE
HV-
Figure 16. Recommended supply and sense resistor connections.
11
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