VLA500 Powerex, Inc., VLA500 Datasheet - Page 7

• Manufacturer Part Number: VLA500
• Description: Hybrid Ic Igbt Gate Driver + Dc/dc Converter
• Manufacturer: Powerex, Inc.

Powerex, Inc., 200 E. Hillis Street, Youngwood, Pennsylvania 15697-1800 [phone]
VLA500-01
Hybrid IC IGBT Gate Driver +
DC/DC Converter
Rev. 2/08
Figure 2. VLA500-01 Desaturation Detector
SET FAULT SIGNAL
SLOW SHUTDOWN
DISABLE OUTPUT
ENABLE OUTPUT
CLEAR FAULT
V CE > V SC
V CE > V SC
WAIT t timer
SIGNAL
SIGNAL
SIGNAL
START
DELAY
INPUT
INPUT
OFF
t trip
ON
IS
IS
IS
IS
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
voltages. When R
time of the IGBT will also increase. If the delay be-
comes long enough so that the voltage on the detect Pin
30 is greater than V
driver will erroneously indicate that a short circuit has
occurred. To avoid this condition the VLA500-01 has
provisions for extending the t
capacitor (C
22). A curve showing the effect of adding C
is given in the characteristic data section of this data
sheet. The waveform defining trip time (t
in Figure 3. If t
not to exceed the short-circuit withstanding capability
of the IGBT module. Normally this will be satisfied for
Powerex NF and A-Series IGBT modules as long as the
total shut-down time does not exceed 10µs.
Adjustment of Soft Shutdown Speed
As noted above the VLA500-01 provides a soft turn-off
when a short circuit is detected in order to help limit the
transient voltage surge that occurs when large short
circuit currents are interrupted. The default shutdown
speed will work for most applications so adjustment is
usually not necessary. In this case C
In some applications using large modules or parallel
connected devices it may be helpful to make the shut-
down even softer.
connecting a capacitor (C
the effect of C
in the characteristic data section of this data sheet. The
waveform defining the fall time characteristics is shown
in Figure 3.
SHORT CIRCUIT
Figure 3. Adjustment of t trip and Slow Shutdown Speed
FAULT SIGNAL
(PIN 30 OPEN)
PROTECTION
DIAGRAM
(PIN 23)
(PIN 28)
TIMING
-5V
V O
trip
S
) between Pin 29 and V
t trip
trip
on short circuit fall time (t
90%
50%
is extended care must be exercised
G
SC
t 1
is increased, the switching delay
10V
This can be accomplished by
10%
at the end of the t
S
) at Pin 27. A curve showing
t 2
trip
t timer
delay by connecting a
S
EE
can be omitted.
trip
1
(Pins 21 and
trip
, t
) is shown
trip
2
delay the
) is given
on time
10V
7