1
2
3
4
8
7
6
5
I
0.1 µF
F
I
= 7 to 16 mA
F
V
= 15
CC
to 30 V
+
–
t
t
f
r
500 Ω
+
V
O
–
90%
10 KHz
50% DUTY
CYCLE
47 Ω
50%
10%
V
3 nF
OUT
t
t
PHL
PLH
Figure 23. tPLH, tPHL, tr, and tf Test Circuit and Waveforms.
V
CM
δV
V
CM
1
2
3
4
8
7
6
5
=
δt
∆t
I
F
0.1 µF
A
B
0 V
∆t
+
–
+
–
V
O
5 V
V
= 30 V
CC
V
V
OH
V
O
SWITCH AT A: I = 10 mA
F
V
O
OL
SWITCH AT B: I = 0 mA
F
+
V
= 1500 V
CM
Figure 24. CMR Test Circuit and Waveforms.
routing the IGBT collector or
Applications Information
Eliminating Negative IGBT
Gate Drive
To keep the IGBT firmly off, the
HCPL-3150 has a very low
maximum VOL specification of
1.0 V. The HCPL-3150 realizes
this very low VOL by using a
DMOS transistor with 4 Ω
the IGBT gate is shorted to the
emitter by Rg + 4 Ω. Minimizing
Rg and the lead inductance from
the HCPL-3150 to the IGBT gate
and emitter (possibly by
mounting the HCPL-3150 on a
small PC board directly above the
IGBT) can eliminate the need for
negative IGBT gate drive in many
applications as shown in Figure
25. Care should be taken with
such a PC board design to avoid
emitter traces close to the HCPL-
3150 input as this can result in
unwanted coupling of transient
signals into the HCPL-3150 and
degrade performance. (If the
IGBT drain must be routed near
the HCPL-3150 input, then the
LED should be reverse-biased
when in the off state, to prevent
the transient signals coupled
from the IGBT drain from turning
on the HCPL-3150.)
(typical) on resistance in its pull
down circuit. When the
HCPL-3150 is in the low state,
HCPL-3150
+5 V
1
2
3
4
8
V
= 18 V
CC
+ HVDC
270 Ω
0.1 µF
+
–
7
Rg
Q1
3-PHASE
AC
CONTROL
INPUT
6
5
74XXX
OPEN
COLLECTOR
Q2
- HVDC
Figure 25. Recommended LED Drive and Application Circuit.
1-206
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
