Author Topic: Can be cheap DC/DC bricks used to power gate driver ?  (Read 788 times)

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Offline MiyukiTopic starter

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Can be cheap DC/DC bricks used to power gate driver ?
« on: March 19, 2020, 05:33:51 pm »
Hi folks,

just a quick question, will common DC/DC brick work reliable as insulated gate power ?
They commonly dont have much specifications about them. Just DC voltage and some vague capacity.

Will they work with 400V transients at output side / high side driver ?
 

Online wraper

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #1 on: March 19, 2020, 05:45:25 pm »
Quote
will common DC/DC brick work reliable as insulated gate power ?
They will work as power source for gate driver but not as gate driver itself.
Quote
Will they work with 400V transients at output side / high side driver ?
Look at isolation voltage spec. Also if there is high isolation capacitance between primary and secondary side, it may be troublesome in some applications.
 

Offline MiyukiTopic starter

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #2 on: March 19, 2020, 06:10:15 pm »
DC/DC bricks designed for gate driving applications have CMTI ratings. Usually specified in kV/us or V/ns.
Oh thanks I see them in catalogue, but they are way more expensive than common ones :/
 

Offline T3sl4co1l

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #3 on: March 19, 2020, 06:30:50 pm »
Yes but...

- The above. Needs high immunity. Not hard to achieve, but if it's not rated, who knows?  Also, if you're using GaN, I would definitely want to see a rating, since the dV/dt is just so high.

- Isolation is usually poor, functional 1kV for example.  This may be technically adequate, but it may also lead to poor reliability versus a proper reinforced barrier.

Expect to pay more for parts with these ratings, or by solving it yourself with a discrete supply (and probably custom magnetics).

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline MiyukiTopic starter

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #4 on: March 19, 2020, 07:19:48 pm »
I dont want to use something exotic like GaN, but even today IGBTs can switch pretty fast (like that Infineon H5 ones can get over 20 V/ns)

I wanted to avoid discrete supply, that is why I asked, but still want to keep it cheap
If discrete supply will be only reasonable way, I still want to avoid custom magnetic if possible

As I look to general purpose ones without immunity they tend to have 5 to 10 times higher capacity between sides
 

Online wraper

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #5 on: March 19, 2020, 07:33:18 pm »
The question is, do you really need it to begin with? What is particular application? Half-bridge gate driver with bootstrap might work just fine without any shenanigans.

 

Offline MiyukiTopic starter

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Re: Can be cheap DC/DC bricks used to power gate driver ?
« Reply #6 on: March 19, 2020, 07:46:29 pm »
wraper: At Half-bridge it is simple, but with buck can be a problem and things like three level inverter ...
 


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