High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

Jan Cumps — Mon, 08 Oct 2018 17:37:04 GMT

I'm busy measuring.

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RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

Jan Cumps — Sun, 21 Aug 2016 19:08:11 GMT

A more detailed capture of the dead band at the rising edge (lower FET closing, higher FET opening)

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RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

Jan Cumps — Mon, 30 May 2016 17:31:34 GMT

I'm on a probing frenzy on the board, on the low-level side.

More to get familiar with where things are on the boards and walking the schematic than for particular measurements.

Here's a capture of the PWM input (white), the HIGH (yellow) and LOW (blue) signals, and the dead band (purple).

The Cursors (and the cursor info) show the duration of the dead band of 53.6 ns.

That's in line with what the user guide of my board says: "The complementary PWM generation circuit creates 50 ns of dead time between both transitions of the PWM signals.".

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As a tribute to @DAB, I have taken care to properly use ground springs on the probes and avoid ringing artifacts on the image caused by sloppy probing.

Frequency is 100 KHz. The input supply to the boards is the minimum, 20 V, to allow me to probe without fear.

RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

jw0752 — Sun, 29 May 2016 05:14:32 GMT

Hi Jan,

You may have the left and right reversed in describing positions of Isolators and GaN in the picture of the daughter board.

John

RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

jw0752 — Sun, 29 May 2016 05:05:50 GMT

Hi Jan,

I have a question about the inductors on the mother board. The wire coming over the tops as pictured would seem to indicate a reversal of direction of the winding. I have not seen this done before and I am wondering if you can give any insight on what is actually being done and why.

John

RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

shabaz — Sun, 29 May 2016 02:12:42 GMT

Hi Jan!

I'm loving your GaN FET series, and was imagining applications.

It seems to me that in the consumer electronics space a car hi-fi amplifier would be an awesome application. They are space constrained yet today tend to be bulky chunks of hot aluminium, so the ability to have smaller, efficient DC-DC converters and audio output stages would seem to fit nicely with GaN FET advantages. But I've only briefly read about these devices. What do you think?

RE: High Voltage GaN FETs - Part 2: Test Setup with LMG3410 Half-Bridge

DAB — Sat, 28 May 2016 19:01:06 GMT

Nice post,

From your pictures it looks like the board can provide a lot of access to the various components, which would be great for anyone wanting to learn more about these devices.

Well done.

DAB