DRV421: about the temp drift of output

user4308845

Part Number: DRV421

-40~80 °C , the temp drift of output is most close to 13mV , moreover, the output drift in the whole temperature range is not regular, and the different module(DRV421+CORE) curves are inconsistent.

my core parameter is N=200,Rhunt=200,G=800uT/A

the drift of drv421 is 5nT/°C，Is this drift regular with temperature?

By calculation the drift output of drv421 is about 3mV

(0.005*120/800)*4=3mV.

Are other drifts caused by magnetic cores?

How do I reduce this parameter?

over 6 years ago

0 Javier Contreras4 over 6 years ago

TI__Mastermind 32260 points

Hello user4308845,

Thanks for using the forum. Please be aware that the 5nT/C is a typical specification and there is a distribution shown in the datasheet (figure 5). The max could be up-to 25nT/C. Also did you get the 800uT/A from simulation? That must be a very small air gap. Please also verify you meet the min inductance for the compensation coil with N= 200.

0 user4308845 over 6 years ago in reply to Javier Contreras4

Intellectual 475 points

when N=200，L=50mH

but when N=1000，Rshunt=1k，the temp drift of output is larger .

I want to know which parameters are affected by inductance value.

0 Javier Contreras4 over 6 years ago in reply to user4308845

TI__Mastermind 32260 points

Inductance is part of the stability of the circuit. You may not see DC errors but it is possible. Please see Designing with the DRV421: Control Loop Stability

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DRV421: about the temp drift of output