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DRV8833: DRV8833 current chopping threshold

Lina Wang
Intellectual 960 points
Part Number: DRV8833

hello sir,

my customer is using DRV8833, infact their application current limit only need about 70mA, DRV8833's the minmues limit current is 2A, so customer want to use their current control funcation to protect motor.

as spec,  Ichop = 200mV/ Rxisen, whether can we set the Ichop on the 70mA, because it is so small value for this IC current limit value, and customer try to set the Rxisen is 5ohm, they said it seems current control isn't work. so we want to know this IChop has low limit value?

  • 0
    TI__Guru** 114905 points
    Hi Lina,

    What is the VM voltage?
    What are the motor specifications? (Voltage rating, current rating, resistance)

    A 5Ohm resistor will limit the current to 40mA +/-20%. There may not be enough current to start the motor.
  • 0 in reply to Rick Duncan
    Intellectual 960 points

    hi sir,

    pls refer motor's spec, and customer have two question:

    1. what is the Rxisen value range limit? spec is no mentioned.

    2. the motor's Stall Current is about 70mA-150mA, whether can use "Rxisen" to set this current?  

  • 0 in reply to Lina Wang
    TI__Guru** 114905 points
    Hi Lina,

    "1. what is the Rxisen value range limit? spec is no mentioned."

    The limit is dependent on the motor. As the motor resistance increases, the resistor can be increased to set the current chop point (Ichop).

    Assuming the VM voltage is 6V, the xISEN pins can be directly connected to GND. This will disable the current limit.

    If the VM voltage is >6V, the xISEN should be connected through a sense resistor. Start with 400mOhms to limit the current during stall to 500mA. The motor should start. If the motor does not start, the resistor can be decreased to 250mOhms to 800mA.

    "2. the motor's Stall Current is about 70mA-150mA, whether can use "Rxisen" to set this current?"

    The motor stall current is listed in the datasheet as < 650mA. Where is the 70mA to 150mA listed?
  • 0 in reply to Rick Duncan
    TI__Guru** 114905 points
    Hi Lina,

    I have not heard back from you in some time, and am assuming your issue has been resolved.

    If it has not, please reply to this post. If the post is locked, please ask a related question by selecting "Ask a related question".