MM9Z1_638 EMC problem

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MM9Z1_638 EMC problem

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Question 1 : When collecting HV current with MM9Z1_638, does the GND of the module need to be connected with ISENSEL?

Question 2: In the BCI experiment, refer to the iso11452-4 standard, the current sampling data fluctuates greatly, and what factors will affect it?

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Q_man
NXP Employee
NXP Employee

Question 1 : When collecting HV current with MM9Z1_638, does the GND of the module need to be connected with ISENSEL?

The MM9Z1_638 is measuring the ISENSE using GND referenced Inputs. The table below (from the datasheet) indicates the limitations / requirements for proper operation:

pastedImage_3.png

VINC    is the voltage from ISENSEH to Gnd and from ISENSEL to Gnd

VIND       is the differential voltage between ISENSEH and ISENSEL

Typically the IC/module GND point should be on the Shunt resistor either the "ISENSEH-side" or "ISENSEL-side".

pastedImage_20.png


ISENSEL side referenced to GNDISENSEH side referenced to GND
Current measurement (ISENSE)I load + I supI load
Voltage measurement (e.g. VSENSE2)V bat + V dropV bat
pastedImage_39.pngpastedImage_40.png

Question 2: In the BCI experiment, refer to the iso11452-4 standard, the current sampling data fluctuates greatly, and what factors will affect it?

Its difficult to give an exhausted answer. In general layout and Grounding has to be carefully handled. In particular avoiding any unwanted currents on the sense lines (ISENSEH/ISENSEL). Maybe you could provide more details? You can send my a direct message by clicking on my name.

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584 Views
Q_man
NXP Employee
NXP Employee

Question 1 : When collecting HV current with MM9Z1_638, does the GND of the module need to be connected with ISENSEL?

The MM9Z1_638 is measuring the ISENSE using GND referenced Inputs. The table below (from the datasheet) indicates the limitations / requirements for proper operation:

pastedImage_3.png

VINC    is the voltage from ISENSEH to Gnd and from ISENSEL to Gnd

VIND       is the differential voltage between ISENSEH and ISENSEL

Typically the IC/module GND point should be on the Shunt resistor either the "ISENSEH-side" or "ISENSEL-side".

pastedImage_20.png


ISENSEL side referenced to GNDISENSEH side referenced to GND
Current measurement (ISENSE)I load + I supI load
Voltage measurement (e.g. VSENSE2)V bat + V dropV bat
pastedImage_39.pngpastedImage_40.png

Question 2: In the BCI experiment, refer to the iso11452-4 standard, the current sampling data fluctuates greatly, and what factors will affect it?

Its difficult to give an exhausted answer. In general layout and Grounding has to be carefully handled. In particular avoiding any unwanted currents on the sense lines (ISENSEH/ISENSEL). Maybe you could provide more details? You can send my a direct message by clicking on my name.