I have been using SiC power modules for my application.Normally we use negative voltages at the gate to turn-off the modules. Would want to know if the power modules can be turned off with the zero voltage at the gate and what are the deviations or effects of it.

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    \$\begingroup\$ Link to the data sheet is required. \$\endgroup\$ – Andy aka Dec 5 '19 at 14:21
  • \$\begingroup\$ Here it is.. d1d2qsbl8m0m72.cloudfront.net/en/products/databook/datasheet/… \$\endgroup\$ – Durgaprasad Dec 5 '19 at 14:24
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    \$\begingroup\$ They are just MOSFETs and MOSFETs can be turned off faster when the gate goes negative. They can be turned off with 0 volts but they'll be slower in turning off and waste more power. \$\endgroup\$ – Andy aka Dec 5 '19 at 14:29
  • \$\begingroup\$ Yes, i even had the same perception but wanted some expert to confirm on that. :) \$\endgroup\$ – Durgaprasad Dec 5 '19 at 14:30


You need to ask yourself why a negative voltage is recommended. If you look at the datasheet for the specific part in question, the gate-source threshold minimum is 1.6V, this means it is guaranteed to be OFF for voltage below 1.6V. Likewise it is guaranteed to be active for a voltage above 4V.

presenting the gate-source with 0V would be below the 1.6V threshold to guarantee the device is OFF, in a non-dynamic situation but this might not be always the case. Take a H-bridge or an inverter, there are other switching devices all producing their own dv/dt. Now consider the parasitic capacitance of the MOSFET. How do you ensure the device is held-off when you command it off, in a power circuit with other switching edges. With a risetime of 70ns, it does not take much capacitance to cause a significant current to flow and potentially turn the device back on.

Driving a MOSFET with Negative Off- State Gate Voltage

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