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DRV8243-Q1: current sense accuracy

Sherry Liang
Genius 10255 points
Part Number: DRV8243-Q1
Other Parts Discussed in Thread: DRV8876, DRV8876-Q1, , DRV8874-Q1

Dear team,

1. My customer has an H-bridge application scenario. When the motor stall current is 0.6A, they need to current sense accuracy is +/-10%. But according to our datasheet, the accuracy can't meet their requirement. Do we have the detailed accuracy for 0.6A? If not, how to achieve customer's such application?

2. When the PWM frequency is 10KHz, and the ambient temp is 125C, what is our max output current we can support? Do we have calculator tool for this?

Thanks & Best Regards,

Sherry

  • 0
    TI__Mastermind 31825 points

    Hi Sherry,

    Thank you for your questions. 

    1. DRV8243-Q1 has good accuracy in higher current 0.8A-4.3A, but not in lower current range as trade off. If customer need +/-10% accuracy in 0.6A, DRV8876-Q1 is our recommendation. DRV8876 has less current capability than DRV8243-Q1, but good enough for 0.6A stall current. Better than +/- 10% accuracy.

    -What is the application for this accuracy requirement. Why +/-10% accuracy is required? 

    2. If customer move to DRV8876-Q1 (or DRV8874-Q1) to have +/-10%, we need to investigate. No calculator is available for DR8874/76, although available in DRV8243-Q1. How much current (continuous? or pulse width?) need under 125C and 10KHz ? We may need to recommend DRV8874-Q1 instead of DRV8876-Q1.

    regards

    Shinya Morita 

  • 0 in reply to Shinya Morita
    TI__Genius 10255 points

    Hi Shinya,

    Thanks for your reply!

    This EE is TMC/thermal management controller. They plan to use our device to drive one small motor with high impedance, so the drive current needed is small. This motor driver to control the heat pump. In this TMC project, in addition to the small motor, there are also large current motor. Therefore they plan to use the same device DRV8243-Q1 to drive both small current motor and large current motor.

    For the +-10% accuracy, it is the system assignment. When Iout is in the range(0.2A, 0.8A), the accuracy is +-20%. They want to know what the accuracy is when Iout=0.6A. Do we have such data? They can accept the accuracy is larger than 10% & smaller than 20%.

    Shinya Morita said:
    -What is the application for this accuracy requirement. Why +/-10% accuracy is required? 

    Could you please send me the calculator of DRV8243-Q1 firstly?

    Shinya Morita said:
    No calculator is available for DR8874/76, although available in DRV8243-Q1.

    Thanks & Best Regards,

    Sherry

  • 0 in reply to Sherry Liang
    TI__Mastermind 31825 points

    Hi Sherry,

    We had internal discussion about this before. We need to stay +/-20% as SPEC for less than 0.8A.

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    TI__Genius 10255 points

    Hi Shinya,

    You seems to miss my second question. Could you please send me the current calculator of DRV8243-Q1? If this tool is not public, you can send me the email.

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Mastermind 31825 points

    Hi Sherry,

    Please refer this link.

    https://www.ti.com/product/DRV8243-Q1

    This is quick reference list in Datasheet.

    regards

    Shinya Morita