Mar 06, 2020
01:50 AM
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Mar 06, 2020
01:50 AM
Hi Infineon,
several times I read about dV/dt induced turn-on? Can you please explain what it means?
Thanks and BR Melanie
several times I read about dV/dt induced turn-on? Can you please explain what it means?
Thanks and BR Melanie
Solved! Go to Solution.
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Mar 20, 2020
02:58 PM
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Mar 20, 2020
02:58 PM
Dear Melanie,
this phenomenon can happen in bridge configurations and is sometimes referred to as "parasitic turn-on". I directly take out the explanation of this Bodo's Power article:
A scenario explaining this effect is shown in Figure 1. The body diode of the low-side switch S2 conducts the load current IL until the high-side switch S1 turns on. After the load current has commutated to S1, the drain-source voltage of S2 starts to increase. During this phase, the rising drain potential pulls up the gate voltage of S2 via the Miller capacitance Cgd. The turn-off gate resistor tries to counteract and pull the voltage down. If this resistor value is not low enough to pull the voltage down, the voltage might exceed the threshold level, leading to a shoot-through and an increase of switching losses.
Please note that while the text and the picture describes a MOSFET, the effect is the same for IGBTs.
Hope this helps!
Best regards,
Klaus
this phenomenon can happen in bridge configurations and is sometimes referred to as "parasitic turn-on". I directly take out the explanation of this Bodo's Power article:
A scenario explaining this effect is shown in Figure 1. The body diode of the low-side switch S2 conducts the load current IL until the high-side switch S1 turns on. After the load current has commutated to S1, the drain-source voltage of S2 starts to increase. During this phase, the rising drain potential pulls up the gate voltage of S2 via the Miller capacitance Cgd. The turn-off gate resistor tries to counteract and pull the voltage down. If this resistor value is not low enough to pull the voltage down, the voltage might exceed the threshold level, leading to a shoot-through and an increase of switching losses.
Please note that while the text and the picture describes a MOSFET, the effect is the same for IGBTs.
Hope this helps!
Best regards,
Klaus
1 Reply
Mar 20, 2020
02:58 PM
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Mar 20, 2020
02:58 PM
Dear Melanie,
this phenomenon can happen in bridge configurations and is sometimes referred to as "parasitic turn-on". I directly take out the explanation of this Bodo's Power article:
A scenario explaining this effect is shown in Figure 1. The body diode of the low-side switch S2 conducts the load current IL until the high-side switch S1 turns on. After the load current has commutated to S1, the drain-source voltage of S2 starts to increase. During this phase, the rising drain potential pulls up the gate voltage of S2 via the Miller capacitance Cgd. The turn-off gate resistor tries to counteract and pull the voltage down. If this resistor value is not low enough to pull the voltage down, the voltage might exceed the threshold level, leading to a shoot-through and an increase of switching losses.
Please note that while the text and the picture describes a MOSFET, the effect is the same for IGBTs.
Hope this helps!
Best regards,
Klaus
this phenomenon can happen in bridge configurations and is sometimes referred to as "parasitic turn-on". I directly take out the explanation of this Bodo's Power article:
A scenario explaining this effect is shown in Figure 1. The body diode of the low-side switch S2 conducts the load current IL until the high-side switch S1 turns on. After the load current has commutated to S1, the drain-source voltage of S2 starts to increase. During this phase, the rising drain potential pulls up the gate voltage of S2 via the Miller capacitance Cgd. The turn-off gate resistor tries to counteract and pull the voltage down. If this resistor value is not low enough to pull the voltage down, the voltage might exceed the threshold level, leading to a shoot-through and an increase of switching losses.
Please note that while the text and the picture describes a MOSFET, the effect is the same for IGBTs.
Hope this helps!
Best regards,
Klaus