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Probably, but the issue is what is starting the oscillations, and why they don't occur when a large impedence is placed inbetween the gates of the paralleled IGBT/mosfet
You are right, if you change the leakage inductance of the short circuit pathway then the frequency of the oscillations...
When you short circuit a module with paralleled MOSFETs or IGBTs, the gate voltage shows huge oscillations, potentially destroying the device.
Why does this happen? This is the reason why manufacturers place additional gate resistors inside the module. They use these additional gate resistors...
You can see the peak I need to detect in the pics
I have a circuit that removes the diode voltage drop but it seems to give out wildly different outputs depending on stabilising capacitors which I dont understand and have no clue about
I will post it later
It is repeating but it will be changing every time (and it is the change that I care about, not the absolute value) so I dont think the comparator option that I have read about and I think you are suggesting will work
I have considered doing this
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I will try it in saturation
In LTspice it works fine but Im not sure LTspice models the recovery from saturation
I have built another circuit that works on the same resistor under the same time time constraints (an opamp integrator) that works...
The saturation delay might not be a problem if its less than 100nS in these 1000V/us slew rate opamps
I also dont know why the opamp stays in saturation even when i discharge the capacitor
Hello
I have a peak detector that detects the peak voltage drop over a resistor that charges a capacitor. Its just an opamp and a diode+ capacitor as you can see, and the capacitor is discharged using the control of the actual gate voltage
However I need to remove the temperature coefficient...
This isn't a problem (yet)
The gate driver works with the RC and one of the diodes in. Its the diode that is clamping to -0.7V that stops the driver working
I see the voltage that Im interested in (input to the opamp) as -0.684... like it should be, but the gate voltage is just stuck at -2.8...
I have modified a concept2 gate driver
I have a low pass filter and then I want to clamp the voltage of this from 0.7V to -0.7V which I feed into an opamp
The diode used to clamp to -0.7V however stops the gate driver working, does anyone have an ideas why?
You can see my schematic
FWIW the...
I have read in several texts the gate-source capacitance expressed in terms of Cox, W, and L.
However I am wondering what its temperature dependence could be? I assume that W and L do not change with temperature, so it must be Cox is the temperature dependent parameter, which I find written as...
I can't seem to find a definitive document that describes the differences, or are they both the same?
Power MOSFETs/transistors vs the type you see in VLSI/CMOS circuits?
Yes I will start with the LCR meter. But I cannot use this in the circuit during the MOSFETs off-state
So what you are saying is that putting Vgs to 1V and measuring peak current is not going to be simple in the real world - perhaps the peak current won't even change a measurable amount from...
I'm not sure I understand your post. I thought increasing the external gate resistance or increasing the internal gate resistance would cause the same behaviour changes?
There is something about propagation delay in Baliga's "Fundamentals of Power Semiconductor Devices" on page 434 which to me...
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