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DRV5057: How to improve the sensing range of DRV5057？

Gabriel Xu
Intellectual 2145 points
Part Number: DRV5057
Other Parts Discussed in Thread: DRV5055-ANGLE-EVM

Hi teams

My customer used a switch hall sensor in BLDC to achieve speed/location detection. But in order to further enhance the resolution and accuracy of the measurement, they plan to replace the switch hall with a linear hall sensor. But I found our linear device, such as DRV5057 the magnetic sensing range is 169mT maximum. As they plan to place this hall sensor in BLDC motor air gap. Normally the flux created by the permanent magnet is about 500mT. So it seems DRV5057 can't directly use in this application scenario.

I wondering to know:

Do we have any workaround solution that could solve such a problem?

How other customers apply linear hall to replace switch hall (without encoder design)

  • 0
    TI__Mastermind 26105 points

    Hello Gabriel,

    Thank you for using the TI forum.  We cannot increase the sensing range of the DRV5057, but you can try to reduce the amount of magnetic field that the sensor will see by adjusting the sensor location/angle.  For example, if you cannot get the sensor farther away, maybe you can move the sensor up or down so that it is not in the the direct path of the strongest magnetic field.  Alternatively, if you are using the TO-92 package, maybe you can rotate the package 90° so that it reacts off of the perpendicular field to the magnet. (This last option is done with the TO-92 devices in the DRV5055-ANGLE-EVM, http://www.ti.com/tool/DRV5055-ANGLE-EVM. This EVM also shows some placement options for the SOT23 packages under the magnet.)