Datasheet

4
Common Mode Transient Immunity
In motor drives and inverters,
there are large voltage transient
generated by switching of the
transistors. Common Mode Tran-
sient Immunity of gate drive
optocouplers is the key attribute
that allow the transmit of accu-
rate information across the
isolation barrier. All Avago Tech-
nologies’ gate drive optocouplers
rely on two key technical
strengths to achieve high Com-
mon Mode Transient Immunity.
The first is use of a proprietary,
low-cost Faraday shield, which
decouples the optocoupler input
side from the output side. The
second method is by unique
package design, which minimizes
input-to-output capacitance. For
proper LED circuit consideration
for ultra high Common Mode
Transient Immunity perfor-
mance, please refer to applica-
tion section of HCPL-3020 and
HCPL-0302 data sheet.
Driving Higher Power IGBT
A non-inverting current buffer,
as illustrated in Figure 6 can be
used to boost the IGBT gate drive
current of HCPL-3020 or HCPL-
0302. Even though the driver is
built from discrete components,
it is necessary to have its own
bypass capacitor placed across
the collectors Q
1
and Q
2
. Prefer-
ably, a smoothing resistor, R is
inserted between the bypass ca-
pacitor of HCPL-3020 or
HCPL-0302 and the bypass ca-
pacitor of the current buffer can
improve noise immunity. The
R
BIAS
can be selected to provide
the required gate impedance
based on the large signal beta of
the driver transistors, Q
1
and Q
2
.
This current buffer should be
placed as close as possible to
IGBT to minimize the parasitic
inductance of the gate charging
and discharging current loop.
If need of higher current arise,
as a leading supplier of gate
drive optocouplers, Avago Tech-
nologies offers gate drive
optocouplers with output cur-
rent as high as 2.A offer in
various packages to meet the re-
quirements. These higher output
current gate drive optocouplers
help to:
- reduce external components
needed for current buffer
- reduce printed circuit board
space for discrete components
- reduce system cost
Table 1. Avago Technologies Gate Drive Optocouplers Portfolio.
Part Number Description Package
HCPL-316J Highly Integrated Single Channel 2.0A Gate Drive Optocoupler SO-16
HCPL-3120 2.0A IGBT Gate Drive Optocoupler DIP-8
HCPL-J312 2.0A IGBT Gate Drive Optocoupler DIP-8
HCNW-3120 2.0A IGBT Gate Drive Optocoupler 8-pin Widebody
HCPL-3150 0.5A IGBT Gate Drive Optocoupler DIP-8
HCPL-315J 0.5A IGBT Gate Drive Optocoupler, Dual Channel SO-16
HCPL-0314 0.4A IGBT Gate Drive Optocoupler SO-8
HCPL-3140 0.4A IGBT Gate Drive Optocoupler DIP-8
HCPL-J314 0.4A IGBT Gate Drive Optocoupler DIP-8
HCPL-314J 0.4A IGBT Gate Drive Optocoupler, Dual Channel SO-16
HCPL-0302 0.2A IGBT Gate Drive Optocoupler SO-8
HCPL-3020 0.2A IGBT Gate Drive Optocoupler DIP-8
1
2
4
3
5
6
7
8
V
CC
R
R
GATE
R
BIAS
Q
1
Q
2
1
2
4
3
5
6
7
8
V
CC
R
R
GATE
R
BIAS
Q
1
Q
2
Figure 6. Current Buffer for Increased Drive Current.