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Gate Driver ICs Forum Discussions

User15728
Level 1
Level 1
Hello everyone. I am developing a 3kw solar inverter circuit. I just want to know if I can drive a single IGBT using unipolar supply (say just +15V). Current flowing through my circuit is between 15-17A and operating frequency is 20 kHz.
It's a general practice to add a negative supply(-5V to -8V) to facilitate speedy IGBT turn-off. I want to know whether it would be safe to skip this additional voltage requirement and replace it by passive methods like additional resistor(small value) arrangement for IGBT turnoff.
If there's any other method for safe igbt turnoff without involving additional voltage supply please let me know.

Best regards and thanks in advance.
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1 Solution
Emanuel
Employee
10 solutions authored 5 solutions authored First solution authored
Employee
Hi akPOW,

Welcome to our forum.

Generally speaking, the bipolar power supply is not only recommended due to the improved switching speeds (and decreased switching losses).
You could use a unipolar power supply for the gate driver, but you will run into the risk of having the IGBT parasitically turned on.
By using a unipolar power supply, the difference between the turn-off gate voltage and the threshold voltage becomes smaller. Thus the device can be parasitically turned-on due to currents flowing though the Miller capacitance or by parasitic inductance in the emitter loop.
Because of this, you should take more care when designing the circuit, especially the gate driver loop and consider using a gate driver with a Miller clamp function, such as: 1ED020I12-F2

you can read more about the drawbacks and considerations of using unipolar power supplies in our application note.

please let me know if you have other questions about this.

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1 Reply
Emanuel
Employee
10 solutions authored 5 solutions authored First solution authored
Employee
Hi akPOW,

Welcome to our forum.

Generally speaking, the bipolar power supply is not only recommended due to the improved switching speeds (and decreased switching losses).
You could use a unipolar power supply for the gate driver, but you will run into the risk of having the IGBT parasitically turned on.
By using a unipolar power supply, the difference between the turn-off gate voltage and the threshold voltage becomes smaller. Thus the device can be parasitically turned-on due to currents flowing though the Miller capacitance or by parasitic inductance in the emitter loop.
Because of this, you should take more care when designing the circuit, especially the gate driver loop and consider using a gate driver with a Miller clamp function, such as: 1ED020I12-F2

you can read more about the drawbacks and considerations of using unipolar power supplies in our application note.

please let me know if you have other questions about this.
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