Embedded Artists iMX RT1062 - Sp2 B: Current Measurement

iMX RT1062 OEM Developer’s Kit - User’s Guide
Page 18
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4.3 SP2b: Current Measurement
It is possible to measure both the main and secondary supply currents on the iMX OEM Carrier board.
 J3 allows measuring the main 3.3V supply by measuring the voltage drop over a 100 milliohm
resistor.
 J4 allows measuring the secondary 3.3V supply by measuring the voltage drop over a 500
milliohm resistor.
200 milliampere over a 100/500 milliohm resistor will give a 20/100 mV drop. A current sense series
resistor is a trade-off between keeping the sense voltage high enough (in all operating conditions)
while keeping the voltage drop low (in the highest current consumption). Insert the short circuit jumpers
in J3 and J4, respectively, to remove the effect of the current sense resistors voltage drop.
It is possible to replace the series resistors with more suitable values for your specific application. The
arrows indicate the current flow direction.
Figure 13 – Location of Current Measurement Connectors J3 and J4
Note that the main 3.3V supply powers both the iMX RT1062 OEM board and peripherals on the iMX
OEM Carrier board, like LCD, SD interface, Audio codec, CAN interface, LEDs, etc. For better
discrimination and resolution of current measurement, it is possible to measure currents on the iMX
RT1062 OEM board also. The following detailed measurements of currents on the iMX RT1062 OEM
board can be done:
 J1 allows measuring the 3.3V supply to DCDC_IN by measuring the voltage drop over a 20
milliohm resistor.
 J2 allows measuring the VDD_SOC_IN core current by measuring the voltage drop over a 20
milliohm resistor.
 J3 allows measuring the 3.3V supply to VDD_HIGH_IN by measuring the voltage drop over a
20 milliohm resistor.
 J4 allows measuring the VBAT current to VDD_SNVS_IN by measuring the voltage drop over
a 1 ohm resistor.
 J5 allows measuring the 3.3V supply to VDD_ADC_3P3 by measuring the voltage drop over a
20 milliohm resistor.
Current Measurement (3.3V DCDC)
J3/R11
Measure current over a 100 milliohm resistor
Current Measurement (3.3V always-on)
J4/R23
Measure current over a 500 milliohm resistor
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