Remember that like every diode zener diode have a capacitance so with series driver resistance you create an RC filter that slows down MOSFET switching time and therefore you increase switching losses. Moreover in real world circuits with proper layout and if driver have stable power supply the overvoltage doesn't come from driver but from upper MOSFET switching in Half-Bridge that charges miller capacitance of bottom MOSFET.
Inductive loads are going to respond to whatever signal you put into them. The point of the FET is to translate the low level decision making to the heavy lifting portion that makes sense for the induction (solenoids, motors, etc). If the logic level side of the FET is protected, then the load side won't notice a different. However, if levels breach or the nature of the waveform changes from what you're intending then the motor will react to the frequency content. Hope that helps!
Great tutorial. I have a grid tie inverter that has 4 IGBTs FGL60N100BNTD and each one has a smd zener diode between gate and source. Would you know what value the diodes should be, please. Many thanks
For an igbt that might be a little different...consult the datasheet for the transistor and determine the application context a little more tightly (like what kind of control signals are actuating these devices). I don't typically use igbts but the terminal vernacular is gate, emitter, and collector... igbts are basically a mosfet controlling a bjt. They do that because mosfets are fast and bjts conduct better in higher power applications (best of both worlds kind of thing). So, anyway, try to learn more about the drive system and design from there! Good luck!
Interesting I love building circuit but indeed help with understanding how mosfet work in inverter why I ask is because I build and inverter circuit but I can’t get the mosfet to switch in conditions mood to power the transformer I flow all the right instructions on a circuit i same on RUclips but I can get the mosfet to conduct is it the transformer why the mosfet not inverting I use a low frequency transformer and high frequency transformer to the high one only buzzz and no voltage so I need some information about what am doing wrong
Hello, does this data sheet specification "Vgs - Gate-Source Voltage: - 10 V, + 10 V" apply to what you are showing in the video? As in, do not supply more than plus or minus 10V to the gate from the driver? Gate-Source is confusing due to the MOSFET having a "source" pin. Does it really mean Driver-Gate Voltage?
It may be in how you're understanding electronics terminology. There isn't really ever such a thing as a driver voltage without also specifying a driver return (or often called ground). Voltage always has two points of reference and that's why it is sometimes called "potential difference." So, if the voltage between the gate and source exceeds the limit for that device, then my recommendation is to avoid encroaching or tresspassing the border. Most MOSFETs have plus/minus 20 V limit between gate and source pins. Exceeding voltage limits between two places for most devices usually ends up in some kind of dieletric breakdown effects and several orders of magnitude change in resistance (failure mode: coerced permission; such as megaohms to single digit kilo-ohms). In applications which use MOSFETs in a highside position, it's possible to have voltages of gate to the system "ground" much higher than the limit between gate and source (because the source isnt connected to ground). The MOSFET only cares about itself...so if the application space or ecosystem that it's in is friendly to the device's limits, it'll behave the way it was designed or expected to.
@@pauljstar Thanks, I do understand potential difference, however I also appreciate the additional info you took time to share. Always willing to listen and learn.
@@anondusery1271 of course, sorry if it felt weird. I never know where people are at or how they learned to speak about electronics. I taught some MSEEs while I was at ASC and you'd be surprised what crutch concepts were holding them together...so I don't like to assume anything anymore haha. Is there still something you wanted to know about gate-source limits? 🤔
But MUCH larger junction capacitance too (because of the larger silicon area to absorb the energy). That's why zeners are preferred for this application because their junction capacitance is much smaller and they work just as well (fast) for low energy pulses.
Perhaps I will! I like doing theoretical models first and then updating with empirical model data. The theory gives you a range of what to expect and then the lab gives you reality haha
Volumes low. But youve got one of those very few voices that I can listen to and lap what yr saying without getting pissed off. kudos.
Remember that like every diode zener diode have a capacitance so with series driver resistance you create an RC filter that slows down MOSFET switching time and therefore you increase switching losses. Moreover in real world circuits with proper layout and if driver have stable power supply the overvoltage doesn't come from driver but from upper MOSFET switching in Half-Bridge that charges miller capacitance of bottom MOSFET.
Accurate!
Hi. Does this apply to inductive loads as well as to the logic level signal?
Inductive loads are going to respond to whatever signal you put into them. The point of the FET is to translate the low level decision making to the heavy lifting portion that makes sense for the induction (solenoids, motors, etc). If the logic level side of the FET is protected, then the load side won't notice a different. However, if levels breach or the nature of the waveform changes from what you're intending then the motor will react to the frequency content. Hope that helps!
Great tutorial. I have a grid tie inverter that has 4 IGBTs FGL60N100BNTD and each one has a smd zener diode between gate and source. Would you know what value the diodes should be, please. Many thanks
For an igbt that might be a little different...consult the datasheet for the transistor and determine the application context a little more tightly (like what kind of control signals are actuating these devices). I don't typically use igbts but the terminal vernacular is gate, emitter, and collector... igbts are basically a mosfet controlling a bjt. They do that because mosfets are fast and bjts conduct better in higher power applications (best of both worlds kind of thing). So, anyway, try to learn more about the drive system and design from there! Good luck!
Interesting I love building circuit but indeed help with understanding how mosfet work in inverter why I ask is because I build and inverter circuit but I can’t get the mosfet to switch in conditions mood to power the transformer I flow all the right instructions on a circuit i same on RUclips but I can get the mosfet to conduct is it the transformer why the mosfet not inverting I use a low frequency transformer and high frequency transformer to the high one only buzzz and no voltage so I need some information about what am doing wrong
What inverter see you using? What are you trying to do?
Can’t this circuit applies to high and low side in a inverter circuit
Yes it can! Make certain to place the zener between the correct nodes (line input and highside power supply)
Hello, does this data sheet specification "Vgs - Gate-Source Voltage: - 10 V, + 10 V" apply to what you are showing in the video? As in, do not supply more than plus or minus 10V to the gate from the driver? Gate-Source is confusing due to the MOSFET having a "source" pin. Does it really mean Driver-Gate Voltage?
It may be in how you're understanding electronics terminology. There isn't really ever such a thing as a driver voltage without also specifying a driver return (or often called ground). Voltage always has two points of reference and that's why it is sometimes called "potential difference." So, if the voltage between the gate and source exceeds the limit for that device, then my recommendation is to avoid encroaching or tresspassing the border. Most MOSFETs have plus/minus 20 V limit between gate and source pins. Exceeding voltage limits between two places for most devices usually ends up in some kind of dieletric breakdown effects and several orders of magnitude change in resistance (failure mode: coerced permission; such as megaohms to single digit kilo-ohms). In applications which use MOSFETs in a highside position, it's possible to have voltages of gate to the system "ground" much higher than the limit between gate and source (because the source isnt connected to ground). The MOSFET only cares about itself...so if the application space or ecosystem that it's in is friendly to the device's limits, it'll behave the way it was designed or expected to.
@@pauljstar Thanks, I do understand potential difference, however I also appreciate the additional info you took time to share. Always willing to listen and learn.
@@anondusery1271 of course, sorry if it felt weird. I never know where people are at or how they learned to speak about electronics. I taught some MSEEs while I was at ASC and you'd be surprised what crutch concepts were holding them together...so I don't like to assume anything anymore haha. Is there still something you wanted to know about gate-source limits? 🤔
Probably a good video, but I cannot hear the audio
Thanks I'll work on the audio
Try a TVS diode. Much faster response time than a zener
Agreed, provided you have money 💰
But MUCH larger junction capacitance too (because of the larger silicon area to absorb the energy). That's why zeners are preferred for this application because their junction capacitance is much smaller and they work just as well (fast) for low energy pulses.
Why don’t you just do a real world dead bug… bloody sims are nothing like real life
Perhaps I will! I like doing theoretical models first and then updating with empirical model data. The theory gives you a range of what to expect and then the lab gives you reality haha
If your simulation doesn't replicate real world conditions you are either...
1). Using a poor component model
2). Your simulation is wrong.