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Author Topic: Reliable and Flexible Switching System  (Read 53196 times)

avalon

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Re: Reliable and Flexible Switching System
« Reply #45 on: April 30, 2014, 02:01:30 AM »
Hey Avalon,

Nice unit but the RDS on is 1.6 Ohm we need a way lower RDS on 1.6 mOhm maybe.

All the Best

  Chris

You are right. Besides, as always we should consider a reasonable price-reward ratio.

~A

lost_bro

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Re: Reliable and Flexible Switching System
« Reply #46 on: April 30, 2014, 02:31:57 AM »
Also, while we are on the subject, consider this as well...

Use it with IXDD415 and the result could be quite awesome.

~A

Good day Avalon

That is one kick-ass integrated driver chip.......Input signal-T T L or C M O S compatible.

Each output of the IXDD415 can source and sink 15A of peak current while producing voltage rise and fall times of less than 3ns.

And The voltage range is from 8V to 30V so, it is compatible with the higher voltages needed for SiC MOSFETs.

Just need to work on the isolation part....

I have used the IXDD family of drivers and they are IMPRESSIVE.

take care, peace
lost_bro

avalon

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Re: Reliable and Flexible Switching System
« Reply #47 on: April 30, 2014, 03:12:11 AM »
Good day Avalon

That is one kick-ass integrated driver chip.......Input signal-T T L or C M O S compatible.

Each output of the IXDD415 can source and sink 15A of peak current while producing voltage rise and fall times of less than 3ns.

And The voltage range is from 8V to 30V so, it is compatible with the higher voltages needed for SiC MOSFETs.

Just need to work on the isolation part....

I have used the IXDD family of drivers and they are IMPRESSIVE.

take care, peace
lost_bro

As far as I am concerned, these are the best you can get.
For quick and dirty apps I routinely use IXD_609 and very happy with the results.

~A

lost_bro

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Re: Reliable and Flexible Switching System
« Reply #48 on: April 30, 2014, 03:28:14 AM »
As far as I am concerned, these are the best you can get.
For quick and dirty apps I routinely use IXD_609 and very happy with the results.

~A

Good evening Avalon

Yes, the IXD_609SI has the integrated schmidt trigger logic for waveform shaping....

I just purchased a lot of IXDD614CI which likewise have the Schmidt logic, I like the CI package because it is a
TO-220 5 pin package so I can heat sink mount along with the MOSFETs..... works like a charm.

take care, peace
lost_bro

avalon

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Re: Reliable and Flexible Switching System
« Reply #49 on: April 30, 2014, 09:45:52 PM »
I like the CI package because it is a
TO-220 5 pin package so I can heat sink mount along with the MOSFETs..... works like a charm.

What a great idea! I am definitely going to get some of those.
Thanks for a super advice.

~A

EMJunkie

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Farmhand

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Re: Reliable and Flexible Switching System
« Reply #51 on: May 04, 2014, 05:28:24 AM »
Anyone want to list some pro's and cons for Half bridge and Full Bridge switching solutions for inductive loads ?

Pro's and cons for transformer gate drives and Hi-Lo IC gate drivers ? eg. IRS2110 http://pdf1.alldatasheet.com/datasheet-pdf/view/145601/IRF/IRS2110.html

..

MarkE

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Re: Reliable and Flexible Switching System
« Reply #52 on: May 04, 2014, 08:08:06 AM »
Anyone want to list some pro's and cons for Half bridge and Full Bridge switching solutions for inductive loads ?

Pro's and cons for transformer gate drives and Hi-Lo IC gate drivers ? eg. IRS2110 http://pdf1.alldatasheet.com/datasheet-pdf/view/145601/IRF/IRS2110.html

..
A single transistor and flyback diode give you a backwards sawtooth current waveform:  The current rises quickly (assuming that the drive voltage is much greater than Irated/Rwinding) when the transistor is on and decays slowly recirculating through the inductor and the flyback diode.  The minimum current is set by the input voltage, the coil inductance, the switch minimum on time, and the switching period.

A half-bridge can manage zero average current in the inductor.  You need to make sure that the top and bottom transistors do not conduct at the same time or else you will have shoot through currents that can be very large and destructive.  Half-bridges are common in switching power supplies, and used in sets of three for three phase power supplies and motors.

A full-bridge can manage current in either direction in the inductor.  It is more flexible in that regard than a half-bridge.  It has the same issues as a half bridge, and current must flow through two switches increasing conduction losses.  Full bridges are the preferred form for DC motor and hybrid stepper motor drives.  The ST Micro L298 dual H bridge has been around for almost 30 years.  There are now much more advanced devices for steppers.

Transformer gate drives cannot support DC operation and fast turn-on and turn-off.  There are configurations of transformer drive that support DC using rectifiers and filters on the gate side of the transformer, but they have slow turn-off. 

ICs support DC operation for low side drivers.  Many high side driver ICs drive N channel MOSFETs using charge pumps.  These require that the low side switch turn on periodically in order to recharge the charge pump.  That can be gotten around by various means if needed using extra circuitry.

Use what works for the application and that you can easily obtain.

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #53 on: May 06, 2014, 04:05:08 AM »
Thanks Mark, I might use the Data sheets and draw up a driver and Half Bridge switch circuit. I already have some IRS2110 driver chips but they are not very high current parts, maybe they can work with moderate frequencies driving IRF460's or FGA25N120-ANTD (IGBT).

If I post a schematic and test the circuit and switching wave forms maybe some folks can suggest improvements. I remember last time i set up an IRS2110 chip and switches I had some trouble with the high side drive initially.

Ta

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #54 on: May 06, 2014, 11:07:15 PM »
Looking at this page http://www.powerguru.org/the-half-bridge-circuit-revealed/ and the circuit in the data sheet pdf below I made these drawings, I must confess using some kinds of IC's confuses me and this is one of them.

Can anyone see any problems with the circuit for the IRS2110 ? I know some gate resistors may be needed, if I could get operation up to about 25 or 30 kHz I would be happy. Even if I could get good operation up to a few hundred Hz I would be satisfied to begin with.

The circuit with the two batteries just signifies a split EMF. The other one with the capacitor in series with the load coil is kinda like the one from the web page above, he uses a different driver chip.

 

MarkE

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Re: Reliable and Flexible Switching System
« Reply #55 on: May 07, 2014, 03:13:31 AM »
Looking at this page http://www.powerguru.org/the-half-bridge-circuit-revealed/ and the circuit in the data sheet pdf below I made these drawings, I must confess using some kinds of IC's confuses me and this is one of them.

Can anyone see any problems with the circuit for the IRS2110 ? I know some gate resistors may be needed, if I could get operation up to about 25 or 30 kHz I would be happy. Even if I could get good operation up to a few hundred Hz I would be satisfied to begin with.

The circuit with the two batteries just signifies a split EMF. The other one with the capacitor in series with the load coil is kinda like the one from the web page above, he uses a different driver chip.
So one thing that you need to make sure of is that the circuit switches low periodically to recharge C4.  I have not looked to see if the driver chip you are using has undervoltage protection for both the high side and low side driver.  Another thing that you should consider is a two resistor and one Schottky diode network in series with each gate to suppress oscillations and optimize the waveshape.  But the BIG thing here is that you have placed your load in series with a capacitor.  The circuit you are deriving from had two stacked power supplies.  If you don't want to have stacked power supplies, and your load isn't across your output capacitor, then build a full bridge.

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #56 on: May 16, 2014, 12:21:10 PM »
Thanks Mark I appreciate the tips, I think SeaMonkey already tried to school me on this and from memory I think had this IRS2110 Hi-Lo driver chip working with a capacitor voltage doubler but I failed to draw the circuit that worked for me. I'm having issues but I need to work it out myself to learn properly, I think. So I found a couple of application notes pdf's on these drivers, at first glance they might help me, if not I'm missing something, I think I'll check my solderless board for cross rail "shorts", for some reason both mosfets are half on with the circuit not even powered up. I pull em out they turn off.

I'm using the signal splitting/dead time control part of the circuit below to process the picaxe output into two 48% duty out of phase signals at 10000 kHz to test the driving circuit. I can adjust the dead time if need be to keep appropriate dead time at the switches if I can get the driver IC to work properly  ::) signals out of the CD4001 are very good.

Anyway maybe the application notes will help someone else as well.


Driver IC application notes.
http://www.irf.com/technical-info/appnotes/an-978.pdf

http://www.irf.com/technical-info/appnotes/an-1123.pdf

..

MarkE

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Re: Reliable and Flexible Switching System
« Reply #57 on: May 16, 2014, 01:30:14 PM »
Thanks Mark I appreciate the tips, I think SeaMonkey already tried to school me on this and from memory I think had this IRS2110 Hi-Lo driver chip working with a capacitor voltage doubler but I failed to draw the circuit that worked for me. I'm having issues but I need to work it out myself to learn properly, I think. So I found a couple of application notes pdf's on these drivers, at first glance they might help me, if not I'm missing something, I think I'll check my solderless board for cross rail "shorts", for some reason both mosfets are half on with the circuit not even powered up. I pull em out they turn off.

I'm using the signal splitting/dead time control part of the circuit below to process the picaxe output into two 48% duty out of phase signals at 10000 kHz to test the driving circuit. I can adjust the dead time if need be to keep appropriate dead time at the switches if I can get the driver IC to work properly  ::) signals out of the CD4001 are very good.

Anyway maybe the application notes will help someone else as well.


Driver IC application notes.
http://www.irf.com/technical-info/appnotes/an-978.pdf

http://www.irf.com/technical-info/appnotes/an-1123.pdf

..
Those are excellent application notes that cover the subject of the high side bootstrap power supply very well.  10MHz is very fast for power MOSFETs.  Is that your timing resolution, or your cycle time?  A good frequency range to work with MOSFETs without too much worry is between 50kHz and 300kHz.  Slower and the output filter energy starts to get big.  Faster and you have to start paying a lot more attention to layout issues which are much worse using a solderless breadboard than on a circuit board.

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #58 on: May 16, 2014, 02:04:42 PM »
OK Now I see the problem, I'm sure you'll find it easy to believe that I had the driver chip upside down hahaha, no harm done it works exactly as it should I think in bootstrap mode, it can be used with a floating supply as well.

The drive circuit posted above with the split supply is basically from the data sheet and works ok but I'll check it to be sure.

I used a 1 uF bootstrap capacitor, and the test setup is 12-24 volts supply.

No not 10 mHz, 10 kilohertz from the picaxe to the signal splitter and 5 kHz to each mosfet 48% duty for the test to see if i have the circuit right.  :) scope capture attached.

Some more reading and I can set to work.

P.S. IRF840's were being driven while the shot was taken.

..

MarkE

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Re: Reliable and Flexible Switching System
« Reply #59 on: May 16, 2014, 02:47:53 PM »
OK Now I see the problem, I'm sure you'll find it easy to believe that I had the driver chip upside down hahaha, no harm done it works exactly as it should I think in bootstrap mode, it can be used with a floating supply as well.

The drive circuit posted above with the split supply is basically from the data sheet and works ok but I'll check it to be sure.

I used a 1 uF bootstrap capacitor, and the test setup is 12-24 volts supply.

No not 10 mHz, 10 kilohertz from the picaxe to the signal splitter and 5 kHz to each mosfet 48% duty for the test to see if i have the circuit right.  :) scope capture attached.

Some more reading and I can set to work.

P.S. IRF840's were being driven while the shot was taken.

..
5kHz sounds much more reasonable.  The waveforms show the dead time that you intend.  It sounds like you are off to the races.