VLA502-01 Ver la hoja de datos (PDF) - Powerex

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VLA502-01

Hybrid IC IGBT Gate Driver + DC/DC Converter

Powerex 

Powerex, Inc., 200 E. Hillis Street, Youngwood, Pennsylvania 15697-1800 (724) 925-7272

VLA502-01

Hybrid IC IGBT Gate Driver +

DC/DC Converter

START

VCE I>S VSC

NO

YES

IS

INPUT

SIGNAL

ON

NO

YES

DELAY

ttrip

YES

VCE I>S VSC

NO

YES

SLOW SHUTDOWN

DISABLE OUTPUT

SET FAULT SIGNAL

WAIT ttimer

YES

IS

INPUT

SIGNAL

OFF

NO

YES

CLEAR FAULT

SIGNAL

ENABLE OUTPUT

Figure 2. VLA502-01 Desaturation Detector

voltages. When RG is increased, the switching delay

time of the IGBT will also increase. If the delay becomes

long enough so that the voltage on the detect Pin 30 is

greater than VSC at the end of the ttrip delay the driver

will erroneously indicate that a short circuit has occurred.

To avoid this condition the VLA502-01 has provisions for

extending the ttrip delay by connecting a capacitor (Ctrip)

between Pin 29 and VEE (Pins 21 and 22). A curve

showing the effect of adding Ctrip on time is given in the

characteristic data section of this data sheet. The wave-

form defining trip time (ttrip) is shown in Figure 3. If ttrip

is extended care must be exercised not to exceed the

short-circuit withstanding capability of the IGBT module.

Adjustment of Soft Shutdown Speed

As noted above the VLA502-01 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 CS can be omitted.

In some applications using large modules or parallel

connected devices it may be helpful to make the shut-

down even softer. This can be accomplished by

connecting a capacitor (CS) at Pin 27. A curve showing

the effect of CS on short circuit fall time (t1, t2) is given

in the characteristic data section of this data sheet. The

waveform defining the fall time characteristics is shown

in Figure 3.

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Figure 3. Adjustment of ttrip and Slow Shutdown Speed

Rev. 8/06

7

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