mlx91205 Melexis Company, mlx91205 Datasheet - Page 8

• Manufacturer Part Number: mlx91205
• Description: Imc Current Sensor Triaxis? Technology
• Manufacturer: Melexis Company

11 Applications Information
11.1 Low current measurement up to ±2 A
Low currents can be measured with the MLX91205 by
increasing the magnetic field via a coil around the sensor.
The sensitivity (output voltage vs. current in coil) of the
measurement will depend on the size of coil and number
of turns. Additional sensitivity and increased immunity to
external fields can be gained by adding a shield around
the coil. The bobbin provides very high dielectric isolation
making this a suitable solution for high voltage power
supplies with relative low currents. The output should be
scaled to obtain the maximum voltage for the highest
current to be measured in order to obtain the best
accuracy and resolution.
11.2 Medium current up to ±30 A
With a single conductor located on the PCB, currents in the
range of up to 30 amps can be measured. The sizing of the
PCB trace needs to take into account the current handling
capability and the total power dissipation. The PCB trace
needs to be thick enough and wide enough to handle the
RMS current continuously.
The differential output voltage for this configuration can be
approximated by the following equation:
Vout = typ. 35 - 40 mV/A * I
For a current level of 30 A, the output will be approximately
1050 mV.
11.3 High current measurement up to ±600 A
Another method of measuring high currents on PCB’s is to
use a large thick gauge copper trace capable of carrying
the current on the opposite side of the PCB. The
MLX91205 should be located near the center of the trace,
however because the trace is wide, the output is less
sensitive to location on the PCB. This configuration also
has less sensitivity due to the distance and wi
conductor.
11.4 Customer Calibration with MCU
In many applications one measures the output voltage of the 91205 with
sensor-system accuracy can be significantly increased by customer calibration of the system after
assembling the 91205 in the application. By applying a known current i.e.100 Amperes, one can calibrate by
means of the microcontroller the output voltage to the exact value i.e. 2.000V at 100 Amps. By doing so, the
offset and sensitivity can be calibrated simply at a certain temperature.
3901091205
Rev 008
IMC Current Sensor (Triaxis™ Technology)
Page 8 of 13
dth of the
a microcontroller. The current-
MLX91205
Data Sheet
May/09