I am using the ADuM5230 gate driver to drive an N-channel MOSFET in a basic buck converter circuit that will convert a 12V DC input to a 5V DC output. The buck converter will operate at a 10kHz frequency and is to drive a 10 ohm load.

Block Diagram of ADuM5230:

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The schematic of the converter on Proteus software:

enter image description here

  1. Capacitors according to datasheet (tantalum & ceramic).
  2. Three-Pin schottky.
  3. Used this MOSFET.
  4. Supplied 5V on Pin 2 and PWM signal on Pin 5, from power supply and signal generator respectively. I will use a micro controller in the future.

When I built the above circuit on a breadboard, I saw a 5V output across the load, as expected. Capacitor values are 10uF and 100nF as specified.

However, when I came to test the circuit on the PCB schematic provided below, the driver only produced 5V between the Viso and GNDiso pins (15 and 14) instead of 15V. The gate driver proceeded to heat up extremely quickly and somehow pulled more than 3A from the power supply. What am I doing wrong here?

PCB layout:

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Track width is T50 and T20, while via size is T70.

Any ideas or suggestions on what could be going wrong?

  • \$\begingroup\$ Gate drivers aren't meant to be used for BJTs. \$\endgroup\$ – Hearth May 11 '18 at 16:51
  • \$\begingroup\$ Applications of this particular gate driver are specifically MOSFET's and IGBT's \$\endgroup\$ – rrz0 May 11 '18 at 16:52
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    \$\begingroup\$ Yes. Your schematic shows BJTs. \$\endgroup\$ – Hearth May 11 '18 at 16:53
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    \$\begingroup\$ Oh, Right! Will edit. That is the FET I provided later. The only reason I did that was due to matching PCB packages. \$\endgroup\$ – rrz0 May 11 '18 at 16:54
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    \$\begingroup\$ If the datasheet says not to connect some pins, don't connect the pins. Try cutting that trace on the board and see if that fixes your problem, though you may have blown your gate driver. \$\endgroup\$ – Hearth May 11 '18 at 17:16

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