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Combining DRV8814 outputs

Freyr Magnusson
Prodigy 10 points
Other Parts Discussed in Thread: DRV8814, DRV8840, DRV8833

Can the DRV8814 h-bridges be combined to act as one of higher capacity by connecting the relevant A and B inputs and outputs in parallel?

If so what do I have to watch out for?

  • 0
    TI__Expert 7455 points

    Hi Freyr,

    To go through the hassle of paralleling DRV8814 into a single H Bridge is not necessary as we did this for you and the device you want to use is the DRV8840. DRV8840 is literally DRV8814 paralleled inside and with all the hooks necessary to make sure nothing goes wrong. This device can drive up to 5A if the heat sink is appropriate.

    You will notice a few differences in between DRV8814 and DRV8840. On DRV8840 now there is a single set of PHASE and ENABLE control signals. Instead of having 2 DAC inputs (AIx pins) the DRV8840 has 5 DAC inputs. This is only meaningful if you want to use the device to drive a stepper and use the internal non linear DAC to cause 32 degrees of microstepping with a sine wave shape. I would just tie them all up to 3.3V if you are going to drive a DC motor.

    All the output pins (AOUT1, AOUT2 and ISENA) need to be connected externally in order to ensure twice the current flowing out of the H Bridge as intended. I think the datasheet does a good job of detailing what you need, so feel free to check it for further information. Or let us know if there are particular items which are not too clear. There is also an EVM for this device which should be available at the moment.

    Hope the info helps. Best regards,

    Jose Quinones 

  • 0 in reply to Jose Quinones
    Prodigy 70 points

    Hi Jose,

    actually we are using DRV8814 in order to drive 2 motors and DRV8840 to drive one motor (which requires more current, up to 4A).

    We are going to produce the two boards in large quantities, we are intersted in using just DRW8814 for both boards: basing on your post, and on some implementation that use DRV8833, we would like to use DRV8814 with the two imput and output connected in parallel.

    Is it a good idea or maybe the few discrepances in the two branches will introduce some unexpected behaviour?

    Best regards

    Bruno Dalvit

  • 0 in reply to tretec
    TI__Mastermind 26065 points

    Hi Bruno

    Parallel the inputs and outputs of DRV8x driver is possible but we really don't have parallel recommendations for all the devices. The following application report maybe help on this topic.

    http://www.ti.com/lit/an/slva320/slva320.pdf

    Best regards,