Mosfet is not turning off at high frequency

  • Thread starter Deleted member 618306
  • Start date

Thread Starter

Deleted member 618306

Joined Dec 31, 1969
0
Hi i am using a driver for driving MOSfet.
Driver output is perfect square wave. But mosfet output is not perfect at high(100khz) frequency.IMG_20190411_165653644.jpg IMG_20190411_165608475.jpg IMG_20190411_165559230.jpg
 

Thread Starter

Deleted member 618306

Joined Dec 31, 1969
0
Mosfet part number: HUF76107D3S
Driver part number: ADP3418

In between driver output and gate there added 180 ohms.
 

DickCappels

Joined Aug 21, 2008
10,152
crutschow wrote "Post #3"

Thank you. Don't know what I would do if you weren't here.

Suggestion: Try reducing the gate series resistor to 10 to 20 ohms. Also, can you show the gate signal, or is that the gate signal in post #8?

If it is the drain signal, the your MOSFET is not turning all the way on quickly.
 
Last edited:

BobaMosfet

Joined Jul 1, 2009
2,110
Put a trace on your gate and on your load and see if load follows gate. If so, it's because your gate is a capacitor, and you're seeing reactance in action at the frequency you're operating at. You may need to choose a mosfet with different gate response.
 

bertus

Joined Apr 5, 2008
22,270
Hello,

In the application schematic in the datasheet of the driver, there is no resistor between the driver and gate.
The resistor will cause a delay in conjunction with the gate capacitance.

Bertus
 

shortbus

Joined Sep 30, 2009
10,045
Is there a pull down resistor from gate to source? A "block diagram" isn't a schematic, so it's hard to tell what the circuit actually is.
 
Top