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Opto and IGBT driver in same IC

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treez

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Hello,
We want to turn some IGBTs on via a gate driver which gets turned ON by an opto.
Though do you know if there is a single IC which is a combination of an opto and a gate driver, for this purpose?
LTspice and schem attached.
 

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  • Hi side IGBT drive.pdf
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  • LTSPICE.zip
    4.8 KB · Views: 123

Vom 1271 is optically isolated gate driver if that's your looking for.
 
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Not sure if VOM1271 does it. It's only slowly turning on (some ms). But really simple solution.
 
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That keyword is "photovoltaic output" for that category.

SiLabs also has their own take as well.
https://www.silabs.com/products/isolation/si875x-isolated-fet-drivers

I've always thought the anemic output currents in the ~10uA category seemed problematic both in terms of switching time and noise immunity but I admit I haven't tested them or fully analyzed this. Does anyone have experience with them?

We're going to make a similar solid state switch implementation soon and may simply use a small isolated supply as both power and control with on/off of the supply determining on/off of the fet.

A signal transformer with a transformer driver and secondary rectifier is another simple scheme that combines power and control.

Also this is a combined power+signal isolator from TI. The ADUM series from Analog also has a similar part (though with terrible efficiency).
https://www.digikey.com/en/product-highlight/t/texas-instruments/isow784x-digital-isolators
 
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What sort of switching speed/peak output current are you looking for?

Broadcom (formerly Avago (formerly Argilent (HP))) makes a wide range of monolithic optoisolator/gate drivers. Some require isolated supplies for the secondary side to deliver several amps (some quite sophisticated with integrated controllers for the isolated supply), others have the above mentioned photovoltaic outputs which are very low current/slow.
 
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Thanks, We're looking for fast as possible switching speed.
Current will be around 5Amps......about 10A when the igbt switches on because of the inrush through the inrush limiters.
Its to switch 5 of our products on at mains peak at the same time.

We'll put in a high side supply for it via a isolated 5w adaptor plug thingy
 

If I understand right, you are designing test equipment, not a retail product. In this case, an industry standard IGBT driver module with built-in DC/DC could be the overall cheapest solution.

Looking at the application, "fast as possible" means µs rather than ns speed. So you don't need excessive high gate currents. A main stream isolated gate driver like TLP350 should do for the driver + isolated DC/DC solution.
 

The HCPL optos look good, but unfortunately cannot be driven by a simple microcontroller output port.

HCPL3120 datasheet
https://www.farnell.com/datasheets/...416.429225948.1507266704-287702491.1506211291

..i am not sure why fig 25 on page 18 has to use a 74 series logic chipdriver...surely a npn bjt would do? (in open collector connection)

The HCPL3120 datasheet (eg fig 22 etc) seems full of connection schemes which improve common mode transient immunity....do you know what all this is about?....in all SMPS's with hi side drives that ive seen, nobody pays attention to common mode transient immunity like the HCPL3120 datasheet...do you know whats going on?

Is the setup of my top post susceptible to common mode transients?
 
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