CGD1700HB3P-HM3 fault generation

CMANDLM

I have connected CGD12HB00D daughterboard up to the CGD1700HB3P-HM3 gate driver with no MOSFET module connected. I put a 12 V DC supply signal across pins 1 and 2 and a square wave 2 Vpp, 1 kHz, 50% duty cycle signal into pins 3 and 4. The gate driver board immediately faults. I also provide that signal when the gate driver is connected to the CAS480M12HM3 MOSFET module and it faults. Please help me understand how I can get the gate driver to operate with a square wave signal.

AustinC

Hi CMANDLM,

The overcurrent protection is immediately detecting a fault because the HS-Drain connection is floating.

When you're using the driver on the bench without connecting it to a module, please connect the HS-Drain spade connector (JT1) to any high-side Source net on the driver to disable the overcurrent protection.

When you're using the driver with your CAS480 module, please connect the HS-Drain spade connector (JT1) to the V+ power terminal on the module to enable overcurrent protection.

Best Regards,

Austin C.

CMANDLM

Austin,

Thank you for noting that. I would like to obtain some clarification. So, when the driver board is operating alone on the bench or I am operating it connected to the MOSFET module without power to the power portion of the MOSFET modules, I should connect the JT1 spade to ground? Or is there some other voltage I should choose?

When I do connect the power connections for the circuit, the JT1 spade should be connected to the high side of the MOSFET module (so the + terminal on the KIT-CRD-CIL12N-HM3)?

AustinC

Hi CMANDLM,

If you're not plugging the gate driver into the module, then connect JT1 to the Source of the high-side such as the outer shell of the gold MMCX connector, JT3. Do not connect the JT1 spade to ground potential.

You're correct, when you're using the module, JT1 should be connected to the V+ terminal on the module or one of the + terminals on the HM3 evaluation kit.

Austin C.

CMANDLM

Austin,

Thank you again. For further clarification, I have found the through hole connections labeled JT3 on the CGD1700HB3P-HM3 board. Above those 5 holes on the board is the designation MMCX, which I assume means that an MMCX connector could be attached to those five terminals. Based on looking at a Molex 0734151471 connector as shown on Digi-Key, any of the four outer through hole connections are connected to the outer shell of the connector. For clarification, this will short the MOSFET if those two points are connected, so it should not be done unless the board is NOT connected to a MOSFET. Otherwise, connect the spade to the + terminal on the MOSFET and it should work even if there is no bias applied to the board (in other words, I am only connecting control signals but not main power to the MOSFET).

Thanks!

AustinC

Hi CMANDLM,

Yes, that is exactly correct. The four outer holes of the MMCX connector's footprint (JT3) are the Source potential, which should only be shorted to the drain (JT1) if the driver is disconnected from the module. While the driver is plugged into the module, the spade connector should be attached to the V+ potential and it will function even if no bias or power is applied to the module.

Best Regards,

Austin