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What is the real current accuracy in VND5025? DS says K1 is 2810 +/- something equal to about 30-35%. Is that steady and can therefore be calibrated away? The current sense ratio drift for K1 is +/- 10%. Should i then add these two if I not calibrate?

Henrik1
Associate
 
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Accepted Solutions
Peter BENSCH
ST Employee

Welcome, @Henrik​, to the community!

Well, the factors K0, K1... are based on a current derived from the load current, which, however, does not have a high-precision reference voltage like an ADC. For this reason, the K factors have a relatively large tolerance and also non-negligible drift. Incidentally, the drift is not to be added to the error of the K-factors, but multiplied.

However, there is the possibility to calibrate the K-factor, which is shown in detail in UM1556, section 2.7.3.

Hope that helps?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

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1 REPLY 1
Peter BENSCH
ST Employee

Welcome, @Henrik​, to the community!

Well, the factors K0, K1... are based on a current derived from the load current, which, however, does not have a high-precision reference voltage like an ADC. For this reason, the K factors have a relatively large tolerance and also non-negligible drift. Incidentally, the drift is not to be added to the error of the K-factors, but multiplied.

However, there is the possibility to calibrate the K-factor, which is shown in detail in UM1556, section 2.7.3.

Hope that helps?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.