DRV411: Does TI offer a DRV411 solution that allows for open loop operation - giving a sampled Hall output voltage

Hello Tim,

Currently we do not have a solution to excite an external hall sensor and provide an output.  We do have the DRV425 that is a fluxgate that with a full scale to about 2mT.  We also have a DRV5053 which is a hall sensor with analog output and has multiple ranges and resolutions available.  There are tradeoffs with both technologies fluxgate and hall sensors.

Advantages for each:

DRV421 - More accurate, Less Drift

DRV5053 - Smaller size, Cost, Larger Range

Please let me know if you require any assistance in evaluating either of these device or in particular cover some more of the tradeoffs.

Thanks for answering. I have used the DRV5053 line, leveraging various sensitivities of parts from the series. They were used in custom open loop current sensing applications.

Do you know of an app note or white paper that TI has written, probably with the DRV411, that would contain application circuits related to Spinning Current Hall Sensor Excitation. That may be a different way to come at a TI solution for the problem.

Tim

Tim,

I am unaware of any papers regarding using the DRV411 or any there ICs to drive a Spinning Current Hall Sensor Excitation. The DRV411 does not have any outputs regarding the hall sensor and needs the feedback loop for normal operation. Syncing to the drive and measurement of the hall sensor would be difficult and I need to verify but it may be optimized for a field closer to zero as that is what it is intended to measure while in a feedback loop. Why can you not use a DRV5053? What benefits would you get from using a discrete hall sensor element?

Thanks for the reply.

I need to measure some higher B-field strengths near 1.5T.

Per the DRV5053 data sheet, the lowest sensitivity part is 11mV/mT.

The output range is ~ +/-1V about an offset of 1V.

This permits measurement of a max B-field of 91mT.

Generally the raw hall effect sensor permits measurement to much higher B-field strengths if not limited by the circuitry built around it.

This is where my question originated.  I am looking for circuit/IC solutions that permit just a raw hall sensor to be attached.

Tim

Tim,

Since we have no papers or TI designs out there I placed some thought in to your problem and I came up with a couple of ideas. 

One is use the DRV411 and come up with a magnetic core that could be compensated using the DRV411.  You then measure the output of the DRV411 to get the magnetic field.  You would need to characterize the core and the magnetic gain.  This may all be too difficult but more detail on your application could prove this to be possible or not.   

Use the ADS124S08 or ADS1247.  These ADC have excitation currents that could be used to drive the hall sensor and also measure the pins.  The downfall of using this is higher cost and software to make the currents create the spinning. 

Thanks for the reply and coming up with a couple of ideas.

I have ordered several of the DRV411 from a distributor and am planning on heading to the lab to see what can be done.

It will be an interesting experiment.  This work may take a while before complete.

Tim

Tim,

Let me know if I can be of any assistance through your experiments.