Hi team,
Could you tell me how to drive UCC21520? How many bias power supply are needed for driving it?
It has high side power supply VDDA and VDDB. Should we need to make two power supply for VDDA and VDDB?
In addition, if we use two UCC21520 for isolated full bridge rectifier circuit, should we make 4 bias power supply?
Regards,
Ochi
Hi Ochi,
When using UCC21520-Q1 in half bridge and full bridge topologies, VDDA/VDDB for both gate drivers can come from a single isolated supply. Having separate bias supplies like you mentioned is not necessary.
However, note that this necessitates using bootstrap circuit to generate the high-side bias (VDDA).
Please see the figure below from the datasheet, where I've highlighted the shared VDD as well as the bootstrap circuit. It also notes that this is typical application for half/full bridge topologies. In this implementation, VDD would be shared on both UCC21520-Q1 ICs.
Below shows fullbridge topology using shared isolated supply + bootstrap circuits for VDDAs.
These links to the datasheet and EVM show how halfbridge/fullbridge is implemented with the single supply for VDDA/VDDB.
This section of the datasheet goes more in depth about the diode/res selection for the bootstrap circuit.
This is an another excellent app note on bootstrap component selection.
If this has answered your question, could you click the green button? And definitely let me know if you have more questions or if something needs to be clarified!
Best
Dimitri
