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Start a SimulationSiC Gate Driver CGD1700HB2M-UNA Tripped on O/C Fault
ANPC inverter using SiC modules (CAB006A12GM3) and an isolated half-bridge gate driver (CGD1700HB2M-UNA) was being tested at 300V. Despite bypassing the gate driver's overcurrent protection by shorting JT4 and JT5, an overcurrent fault was indicated by red DT1/DT2 LEDs at only 0.5A of current. I am seeking help to diagnose why the fault occurred under these conditions, as the current was low and the protection was bypassed.
Comments
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Thank you for your post, it has been approved and we will respond as soon as possible.
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Hi ankitdesh92,
Rather than shorting JT4 to JT5 to disable overcurrent protection, please short JT4 to the low-side source and separately short JT5 to the high-side source. We typically achieve this by soldering a wire from the spade connectors to the exterior shell of the MMCX connectors (JT2 for low-side and JT3 for high-side). I'll post a picture of an example when I swing by the lab later today.
Best Regards,
Austin C.
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Hiiii Austin,
Thank you for the feedback.There is a mistake in the post. I did the same thing as you said. I shorted JT4 to low side source and JT5 to high side source. I am posting a picture of what I did.
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Hi ankitdesh92,
Thank you for the image; that looks perfect. What is the behavior of the driver now? I'm hoping the gate driver wasn't damaged during the initial 300 V operation with JT4 and JT5 shorted.
Best Regards,
Austin C.
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Hi Austin,
Just to let you know. I never shorted JT4 and JT5.It was a mistake in my initial post. The gate driver is in this condition since the start(as per the image) and it still generated the fault red signal on DT-2 and DT1 LEDS. Also ,the gate driver works fine
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Hi ankitdesh92,
Ok, understood, thanks for the additional info. It looks like your implementation of the overcurrent protection defeat is correct. Can you describe the inputs to your board? And when exactly does the driver produce the fault?
Here is the example of one of our gate drivers from the lab:
Thanks,
Austin C.
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The gate driver is receiving the PWM signals from transceiver(CGD12HB00D), which in-turn is receiving signals from a DSP. The gate driver is used to drive SiC MOSFET (CAB006A12GM3).These Mosfet's are driven at 2kHz.These SiC MOSFET's are part of an ANPC Inverter fed from a DC Power Supply. When the DC Power Supply exceeded certain voltage(>300V),the gate driver tripped on the fault. Why do you think the gate driver tripped with the protection bypassed?
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Hi ankitdesh92,
It's possible that noise on the input ribbon cable is causing the driver to fault. How long is your input cable and is it running near any high di/dt cables? We recommend keeping the ribbon cable short wherever possible and running it away from the phase/output of your converter.
We have utilized this gate driver quite frequently in reference designs such as the CRD200DA23N-GMA, in early prototypes of the CRD25DA12N-FMC and the CRD60DD12N-GMB, and in a few custom 3-phase traction inverter designs. I'm quite confident that the driver will work for your application after some initial debugging.
Best Regards,
Austin C.
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Hiiii Austin C,
The input cable is very short and its away from converter outputs.I am trying a few things like ensuring proper connectivity between various circuits to debug the issue.
I have a lot of experience around 2 years with this gate driver. It works really well!!
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Hiiii,
Can you comment on what might be the reason the gate driver trips on overcurrent despite the protection being bypassed. I still find it unusual!
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Hiii Austin,
Is it a good idea to bypass the protection further by shorting out the LS-OC/HS-0C with the LS-Source/HS-Source?
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