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DRV8899-Q1: DRV8899

Part Number: DRV8899-Q1

Hi Sir,

Would you pls help DRV8899 as below? thanks.

1.VREF and STEP are relative or independent? Will it influence speed? Will it influence current?(Start up will be max. current, increase speed will reduce current?)

2.Will VREF circuit are different for DAC or PWM?

3.Can we use voltage divide for VREF design?

4.Can VREF not control if using SPI Interface?

5.Will Step motor need to consider current ripple? 

6.What is Decay Modes?

Thanks, Ian.

  • Ian,

    1. VREF and STEP are independent? STEP pulse frequency sets the speed. VREF voltage sets the winding current.

    2. VREF circuits are different for DAC or PWM. Please check the datasheet.

    3. Yes. You can use voltage divide for VREF design.

    4. If you set VREF higher than 3.3V, it will set the output current to maximum value. Customers can use "TRQ_DAC" register to change the output current setting.

    5. Yes. Step motor need to consider current ripple. It could be related to the output current shape; motor torque; audible noise...

    6. Decay Modes: please check datasheet "7.3.6 Decay Modes"