Re: [CAD_CAM_EDM_DRO] ir2110?

andrew abken wrote:

> Looking at designing a brushed dc motor drive circuit with the ir2110 and
> some igbt's. Needs to run 100 volts at 20 amps under pwm control. Any one
> have any words of wisdom concerning this driver chip and its use? I was
> successful in my effort to build some 30 volt 10 amp motor drives with an
> hip4081/mosfet combo, but I shall not use that chip again, what a mess!

Yup, the specs for the HIP4080 claimed 80 volts, but when you finally get
through to people who know the chip, they tell you 54 V is the limit!
Otherwise, the 4080 was pretty good. I haven't tried the 4081, but it
took a lot of stuff to replace all the control logic on the 4080.

I used two of the IR2113S, and it has worked VERY well. I used an IR2110
in an earlier project.

One of the things that the 4080 does is have a charge pump to keep the
high side bias working even with VERY long pulses. The IR2110 and 2113,
etc. don't have that. I used a pot core transformer driven at 100 KHz by
a 4069 running on 12 V. This way I could rig the PWM control to go to
100% duty cycle without worrying about the bias fading.

Note that IGBTs must NEVER be allowed to operate in the linear region.
They have high gain, but also have positive temperature coefficient. Therefore,
the hottest part of the transistor hogs the current. This is also why paralleling
them is very tricky. So, you want your gate resistor to be as low as you
possibly can get it. You will probably also want RC snubbers on the
output leads to absorb transient energy. Unless you buy IGBTs with
integral high-performance diodes in them, the reverse protection diode
is usually quite bad, and you may need to parallel it with a better external
diode to make sure the internal one never conducts.

The area enclosed by the power switching circuits should be made as
small as possible, as that creates parasitic inductance, where the
above mentioned transients come from.

You should consider L-C output filters. I'm REALLY glad I put these
into my servo amps, as these things would probably wipe out all receivers
within 1000 feet. My (FET) servo amp is running with a 100 KHz carrier.

Jon