K
Klaus Vestergaard Kragelund
Guest
On 26-04-2023 17:38, John Larkin wrote:
think the 1210 is significantly slower
The LMG1020 has 350ps risetime @ 100pF, LMG1210 has 500ps @ 0pF. I don\'tOn Wed, 26 Apr 2023 14:46:53 +0200, Klaus Vestergaard Kragelund
klauskvik@hotmail.com> wrote:
On 26-04-2023 03:05, John Larkin wrote:
On Tue, 25 Apr 2023 17:55:29 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 25 Apr 2023 17:24:04 +0200, Klaus Vestergaard Kragelund
klauskvik@hotmail.com> wrote:
On 25-04-2023 16:31, John Larkin wrote:
On Tue, 25 Apr 2023 13:31:13 +0200, Klaus Vestergaard Kragelund
klauskvik@hotmail.com> wrote:
Hi
We have a GaN FET that is dumping voltage into a capacitor. The GaN
drain is connected to 50V, and the capacitor is connected on the source
of the FET. Sort of like this:
https://www.infineon.com/export/sites/default/_images/product/power/GateDriver/circuit_diagram/Single-High-Side-Driver_Diagram.jpg_1153011823.jpg
\"To load\" is connected to a small 50pF capacitor to ground.
We need to pump current into it very fast for reasons I cannot disclose.
So we turn the high side FET on in about 500ps, and charge the
capacitor. Pretty basic
Where do you get a gate driver that can turn on a GaN fet in 500 ps? I
need that! A little inductance in series with the gate could help
some. The gate resistor will slow things down.
LMG1020
https://www.ti.com/product/LMG1020
2 ohms gate resistor
Nice part. Do you even need a GaN fet?
Shame it\'s a single 5-volt driver, not one of those bootstrap
half-bridge drivers.
One might drive a GaN fet half bridge with two of those. One would be
grounded, but the other would have to float on the source of the upper
fet. Getting power up there would be no big deal, but the logic drive
would be interesting.
In our design we use a digital opto to do the levelshift. Downside is
that the switch node goes to several components so has some capacitance.
One option is to use the LMG1210 which is a high side driver, has a
little slower switching speed however.
Nice but slow.
think the 1210 is significantly slower