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I'm working on a power electronics project where it involves driving 4 different MOSFETs, (3 HighSide and 1 LowSide). Rather than using a different IC for the LowSide driver, I am thinking about using 4 HighSide drivers to drive all the MOSFETs.

I wonder it would have any negative impacts on the circuit as would it damage the LowSide-MOSFET?

It kinda feels to me like that the HighSide driver has a higher part count to support bootstrapping when the LowSide driver needs much less and that's why a LowSide driver is appropriate for a LowSide MOSFET. Also I kinda observed that LowSide drivers are a bit cheaper than HighSide drivers. Are those really the reasons why a LowSide driver is preferred for a LowSide MOSFET?

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    \$\begingroup\$ It's difficult to determine what negative effects you will encounter with just the information given. Can you share the part number and/or datasheet for your high-side driver? \$\endgroup\$ – ζ-- Aug 19 '18 at 1:17
  • \$\begingroup\$ Hi! analog.com/media/en/technical-documentation/data-sheets/… is the datasheet for my HS Driver! \$\endgroup\$ – Blogger Aug 19 '18 at 1:19
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    \$\begingroup\$ All that I see at first glance is "TS (Pin 8): Top (High Side) source connection or GND if used in ground referenced applications." on page 6. This seems promising for allowing low-side use but one would need to read the datasheet more thoroughly. One thing to note is that the charge pump is driven from the higher of VCC and TS, meaning that you could potentially exceed VgsMax with high enough VCC. It's not clear at first if the pump operates up to (TS+12V) or max(TS, VCC) + 12V. \$\endgroup\$ – ζ-- Aug 19 '18 at 1:22
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    \$\begingroup\$ Because there are enough applications where a low-side driver is necessary, and I would bet that a low side driver has considerably simpler internal complexity since it doesn't need as much level shifting, offset voltages, etc. It's a matter of economics as well as engineering. \$\endgroup\$ – ζ-- Aug 19 '18 at 1:34
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    \$\begingroup\$ I would assume that you would be fine on the point that I brought up regarding voltages (although the low side might cut it close, so I wouldn't do this in anything safety critical or important at first). That said, I don't have time right now to do a full reading of the datasheet so other concerns may still lurk. \$\endgroup\$ – ζ-- Aug 19 '18 at 1:37
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Yes, you can use the LTC7004 for driving a low-side switch.

Turn to the diagram of the output stage in the LTC7004 datasheet (fig.1). Connect the TS pin to GND. (The source of the low side N-channel MOSFET is also connected to GND.) Connect the BST to the gate driving voltage. Add a capacitor from BST to GND. Place the capacitor near the BST pin.

Interestingly, the LTC7004 has got an internal charge pump which can generate a +12V gate drive voltage from the Vcc. If you want to create, the gate drive voltage with the internal charge pump, then don't connect BST to an external gate drive voltage. Keep the capacitor between BST and GND.

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