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Forum Index : Electronics : SMPS vs Linear Regulator for Gate Supply

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InPhase

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Joined: 15/12/2020
Location: United States
Posts: 178

Posted: 06:28pm 17 Jun 2021

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I have gone the route of using isolated power supplies instead of charge pumps for gate drive supplies. I am curious if anyone knows of any benefit or drawback of using a switching regulator over a linear IC? I have two isolated AC outputs from a homemade circuit. Currently they power switching regulators to feed the gate supplies.

Haxby

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Joined: 07/07/2008
Location: Australia
Posts: 423

Posted: 09:35pm 17 Jun 2021

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I think either will be fine but layout is important. If the power supplies are far from the MOSFET drivers you should consider common mode chokes as well as filter capacitors.

The aero-sharp inverters have a single switch mode transformer with multiple windings for each driver, each output goes to 15v linear regulators, then through a 10-15cm ribbon cable to the driver circuit. There is a common mode choke at the driver end for each rail.

Also consider what will blow up when MOSFETs fail in short circuit.

if your battery voltage ends up going to the gate, it may take out the power supply for all gates.

Haxby

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Joined: 07/07/2008
Location: Australia
Posts: 423

Posted: 09:39pm 17 Jun 2021

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I like individual converters. Hi-Link does a range of dc-dc converters, and if your batt voltage is 80v or more you can use the ac-dc converters. Cost about $3 each from Ali express. Better quality than the really generic non-potted converters from who knows where.

Warpspeed
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Joined: 09/08/2007
Location: Australia
Posts: 4406

Posted: 10:35pm 17 Jun 2021

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I prefer the small ac-dc converter boards used in the dc wall packs around the world.
These are very efficient, voltage regulated, short circuit protected, low cost, and work from about 40v dc to 400v dc.

Short circuit protection is important if your mosfet or IGBT ever blows up. The gate driver chip will often die as well, but I have never destroyed on of these small power supplies.

Cheers, �Tony.

InPhase

Senior Member

Joined: 15/12/2020
Location: United States
Posts: 178

Posted: 10:54pm 17 Jun 2021

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Thanks for the thoughts guys. The overall setup is a push-pull transformer with two output windings. They get rectified and fed to two $3-$4 adjustable eBay buck converters. I was unsure what the effect, if any, of the small amount of noise inherent in the switch mode output would be on the gate drive.

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