How can I drive an IGBT?

[Electronic Swear]

I have a signal output from a voltage comparator. Topically, its
output voltage is 12V. Now, I would like to use this signal to drive
an IGBT. Of course, if I just direct connect the output pin to the
gate of IGBT, the comparator signal drop down to certain level.

So, how can I add it between the comparator output and the IGBT? The
connection of IGBT is as followed:


311VDC
|
motor
12V signal __|
from ||
comparator o-----||<-- IGBT
output ||__|
|
|
GND

So, how can I connect and add component in between 2 components and
then can drive the IGBT?

 

[Fabio G.]

swear_terence@hotmail.com (Electronic Swear) ha scritto:

However, is there any cheaper or simplier solution?

A simple push-pull emitter follower topology could be used as a current
amplifier to drive the gate of the IGBT.


--
Per rispondermi via email sostituisci il risultato
dell'operazione (in lettere) dall'indirizzo

 

[Electronic Swear]

Fabio G. <7+5@supereva.it> wrote in message news:<uc6c21t1f8tjb98f7g363bgvs4esk3p064@4ax.com>...

swear_terence@hotmail.com (Electronic Swear) ha scritto:

However, is there any cheaper or simplier solution?

A simple push-pull emitter follower topology could be used as a current
amplifier to drive the gate of the IGBT.

Yes, I nearly forget this simple method.
However, I don't want to use an extra component to do so.
Can I use a voltage comparator (LM339) acting as an op amp?

 

[Electronic Swear]

Fabio G. <7+5@supereva.it> wrote in message news:<uc6c21t1f8tjb98f7g363bgvs4esk3p064@4ax.com>...

swear_terence@hotmail.com (Electronic Swear) ha scritto:

However, is there any cheaper or simplier solution?

A simple push-pull emitter follower topology could be used as a current
amplifier to drive the gate of the IGBT.

sorry, I have made a mistake that it should be a push-pull emitter
follower but not a voltage follower by using op amp~

 

[Winfield Hill]

Winfield Hill wrote...

Electronic Swear wrote...

I have a signal output from a voltage comparator. Topically, its
output voltage is 12V. Now, I would like to use this signal to drive
an IGBT. Of course, if I just direct connect the output pin to the
gate of IGBT, the comparator signal drop down to certain level.

So, how can I add it between the comparator output and the IGBT?

What makes you think adding an IGBT will cause the "signal (to)
drop down to certain level."? The IGBT's capacitive gate will
*slow* down the gate-drive signal, but after an RC-style delay
it'll be as large as before. Lots of applications don't mind a
slow switching time. Another point, IGBT gates have much less
capacitance than FET gates, for parts with equal high-current
capability, which reduces any issues arising from this problem.
This said, the 20mA bipolar output drive from an opamp, like an
LM324 or LM358, exceeds the drive available from a comparator.

A typical low-current IGBT might be the HGTP3N60A4D (rated at 8A
and 600V), or the IRG4BC10K (rated at 5A and 600V). The latter
IGBT has 220pF of Ciss gate capacitance, and requires about 10nC
to change switching states (fig 8). This means that a 20mA drive
could switch an irG4bc10k IGBT in less than t = dV C / I = 100ns
cough> ahem, assuming the IGBT can respond that fast. You can
use this basic principle to evaluate your design.

And, I should add, to conclude that for simple on/off operations
with a small IGBT like this, the lower-current gate drive from a
comparator should be fine. For example, 5mA drive would provide
a 0.4us on/off switching speed, which is plenty fast for a motor.


--
Thanks,
- Win

 

[Electronic Swear]

Alan Turner <alan@mrblobbybiccard.com> wrote in message news:<pan.2005.03.02.10.15.55.68950@mrblobbybiccard.com>...

Hi

On Wed, 02 Mar 2005 00:54:46 -0800, Electronic Swear wrote:

I have a signal output from a voltage comparator. Topically, its
output voltage is 12V. Now, I would like to use this signal to drive
an IGBT. Of course, if I just direct connect the output pin to the
gate of IGBT, the comparator signal drop down to certain level.

So, how can I add it between the comparator output and the IGBT? The
connection of IGBT is as followed:


311VDC
|
motor
12V signal __|
from ||
comparator o-----||<-- IGBT
output ||__|
|
|
GND

So, how can I connect and add component in between 2 components and
then can drive the IGBT?


You might consider a driver IC like an IR2110. It depends how fast you
need to the IGBT to switch. The faster you switch the device, the harder
it will be to control transients. I think you need to have a flywheel
diode connected across your motor, or you might blow the IGBT when you
switch it off.

Regards,
Alan

I see~
However, is there any cheaper or simplier solution?
Thanks~