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I am trying to design an ignition coil driver using the FAN1100-F085 IC and a ISL9V3040x3ST−F085C IGBT.

I am having trouble understanding the datasheet when it comes to the current sensing. It says to use a 20 mΩ resistor, but that seems quite small and it not very common.

I followed the typical application schematic to create this schematic with values I think are correct:

enter image description here

How would I create the current sensing part, on a breadboard for testing if even possible, or a pcb? Do I have to use a resistor or can the 20 mΩ be achieved with some kind of trace pattern?

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    \$\begingroup\$ You should be able to find a 4-terminal 20 mOhm current sense resistor fairly easily from Digi-Key or other distributors. This type of circuit shouldn't be breadboarded, you should do a PCB layout. \$\endgroup\$
    – John D
    Commented Jun 19, 2023 at 19:39
  • \$\begingroup\$ ”20 mΩ resistor, but that seems quite small and it not very common” There are 227 different 20 mohm resistors in stock to choose from at DigiKey at the moment. Link: digikey.com/en/products/filter/chip-resistor-surface-mount/… \$\endgroup\$
    – winny
    Commented Jun 19, 2023 at 20:11
  • \$\begingroup\$ Thanks, I should have checked the distributors instead of google. Why a 4 terminal resistor? How can I calculate what wattage it should be? \$\endgroup\$
    – Struner
    Commented Jun 19, 2023 at 20:14
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    \$\begingroup\$ It doesn't have to be a 4-terminal resistor if you're careful about the layout, but if you want best performance it's recommended. See here: bourns.com/docs/technical-documents/technical-library/… \$\endgroup\$
    – John D
    Commented Jun 19, 2023 at 20:49
  • \$\begingroup\$ Thank you, this should get me on my way \$\endgroup\$
    – Struner
    Commented Jun 20, 2023 at 5:52

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