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Original question:

DRV8256: DRV8256,PWM, heat,

DRV8256: DRV8256 motor current measurement

Kami Huang60
Genius 3830 points
Part Number: DRV8256
Other Parts Discussed in Thread: INA190, DRV8876, , DRV8873, DRV8874, DRV8816, TLV9001

Dear Sir/Ms.

Because DRV8874/DRV8876/DRV8873 is out of stock, my customer wants to find replacement materials. His motor specification is 24V, 3A (Max continuous), brushed motor. Looking for TI website, he found DRV8256. But the customer needs to know the current state, so she wants to connect a current detection IC with analog output. His brushed motor has forward and reverse rotation. I suggest INA190 but it doesn't seem to work. Can you give me some suggestions? For example, another motor driver IC, DRV8256 Out Pin current detection method.

Best Regards,

Kami Huang

  • 0
    TI__Mastermind 37683 points

    Hello Kami,

    Kami Huang60 said:
    Can you give me some suggestions? For example, another motor driver IC, DRV8256 Out Pin current detection method.

    The DRV8816 is a good suggestion. However, I see that you have concerns about high temperatures on a different E2E thread. I will reply to that thread soon.

    Another way to implement current sensing with the DRV8256 is by using a SENSE resistor between PGND and GND. However, the voltage drop across the resistor should not be  greater than 0.3V to prevent issues with the LS FET not fully turning on. Below is a rough schematic of how the implementation would look like. For the current sense amplifier, the INA190 should be okay. The max output voltage of the CSA should be less than the max ADC voltage the MCU can process. The gain should be chosen for the appropriate max current that needs to be detected. The REF voltage should come from an amplifier (like the TLV9001 for example) with unity gain. Setting the VREF voltage to around mid-rail (~1.75 when using 3.3V rail) to allow for bidirectional current sensing. If the customer only desires current sensing in one direction, VREF can se tied to GND and the extra amplifier will not be needed.

    Let me know if there are any questions.