DRV421: Differences between DRV401 and DRV421 in Residual Current Detection Applications

Hello user4308845,

Both will have challenges with designing and RCD, Residual Current Detection. Most of the challenges will be with the magnetic design. The DRV421 have the fluxgate internal and the offset is 8uT so with a core gain of 500uT/A that would equate to 16mA of offset error. You will still need to design the magnetic core to deal with external fields and common mode current. The compensation coil also needs to have a minimum of 100mH and this will limit the number of turns that can be decreased by.

The DRV401 the fluxgate probe needs to be designed along with the magnetic core. Here the offset will be more of a system issue but is more flexible.

Both devices will need some magnetic core design and the DRV401 will need a probe field designed. Both have tradeoffs. The DRV421 has a defined offset of the fluxgate while the DRV401 will be dependent of the design.