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DRV8885: DRV8885 Current Setup

Yang Wu
Expert 3080 points
Part Number: DRV8885

Hi Team,

My customer is using DRV8885, for the current regulation, what it means "Full step (2-phase excitation) with 71% current" in the datasheet (page 28)?

Does it mean that, for example, you set 1A threshold and actually it triggers OCP @710mA? 

Because the customer did observe this phenomenon. For 1/16 step, 1/2 step and 1/4 step etc., the measured OCP current conforms to equation (5), but for full step, the setup threshold is 400mA, but the measured OCP is approximately 300mA. 

thanks a lot.

Yang

  • 0
    TI__Guru** 114905 points

    Hi Yang,

    Does it mean that, for example, you set 1A threshold and actually it triggers OCP @710mA? 

    When operating in full step mode, the current is regulated to 71% of the full scale setting. This is shown in Table 3 of the datasheet. Each full step regulates at 71% or -71% of the full scale current.

    OCP is different than current regulation. OCP is overcurrent protection and is triggered if the current exceeds at least 2.3A for at least 1.3us. 

  • 0 in reply to Rick Duncan
    TI__Expert 3080 points

    Hi Rick,

    Thanks for your reply. I made a mistake about OCP, actually I mean the current chopping threshold.

    thanks a lot.

    Yang