I am working with a circuit configuration where a gate driver IC (ISO5852S) is used as a high-side gate driver and the bias supplies of this IC is coming from three isolated DC-DC converters. I intend to use this gate driver for high voltage (close to 10 kV). However, the gate driver IC is rated for maximum 5.7 kV. Hence, isolated DC-DC converters for bias supplies and optical fiber for PWM signal isolation are being used.

That said, whenever voltage level of the DC supply reaches close to 5.5 -6 kV, the gate driver becomes faulty. I am suspecting that the control/input side ground of the gate driver IC being in a floating state is causing the problem.

Any suggestion to solve this problem will be highly appreciated.

Is it practical to use a large valued resistor in between the control and power ground of the gate driver IC and another same valued resistor between the control ground and the input ground of the DC-DC converter so that the control ground has a specific reference voltage?

Thanks in advance.

  • 2
    \$\begingroup\$ A schematic is better than words. You can add one in using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar and "Save and Insert" on the editor an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid. \$\endgroup\$
    – Transistor
    Apr 4 at 17:12
  • \$\begingroup\$ If you use isolated supply and fiber optics, then you aren't using the isolation feature of this driver, right? Why not just connect input and output grounds together then? \$\endgroup\$
    – bobflux
    Apr 4 at 17:19
  • \$\begingroup\$ Initially, I connected the input and output grounds together. That resulted in output signal clamped to negative bias potential (-5V). I assume, it is required to have the grounds disconnected for proper operation. \$\endgroup\$
    – Allison_81
    Apr 4 at 17:24
  • \$\begingroup\$ @Transistor, I will try to draw and upload a schematic when I get a chance to better articulate the problem. \$\endgroup\$
    – Allison_81
    Apr 4 at 17:26
  • \$\begingroup\$ I asked a different question (electronics.stackexchange.com/questions/563183/…) which lead me to the same question which I never had considered before. I solved my problem by adding a large resistor between the 2 grounds. In my case I just had to consider the impact of the leakage current on the circuit and it was perfectly acceptable. IF this is acceptable for your overall circuit and application I will suggest you test connecting the 2 "ground" with a large resistor and see if it solves your issue. \$\endgroup\$
    – jf_vt
    May 3 at 12:02

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