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DRV8312: Do GND_Xs & GNDs pins accept a 0.2~0.3 V ?

Part Number: DRV8312
Other Parts Discussed in Thread: DRV8332,

Hi Motor Drive Team,

To measures the dc-link current instead of phase currents, the GND_A,B,C pins and GND pins are connected all together (at junction A), and a current sensing resistor (Rsense = 0.01 ohm) is placed between the  junction A and the ground of PVDD.

Question is whether  GND_x and GND pins can  accept 0.1~0.3 voltage  to test and calibrate the differential amplification ckt of the current messurement ckt.

Actually the test voltage(0.1V) will be applied to the ternminal of the Rsense. If it is possible, every single board and circuit will be tested.

Thanks

 

  • Hi Sewoong,

    Yes the GND_x and GND pins can accept 0.1~0.3voltage.

    Is there a reason you want to measure the current through the DRV8332 control logic in addition to the dc-link?

    It is recommended to connect the GND pins directly to a common ground. If you connect the GND pins at junction A, please consider the return paths of VDD, GVDD_x and the mcu ground when doing so.

  • Hi Rick,

    I want to measure not all three phase currents (IS-A, B, and C,), but a current (IS-TOTAL) in the return path of the dc-link. (IS_x and IS-TOTAL are in the figure 16 of the data sheet)

    I don't understand the meaning of   "current through the DRV8332 control logic". Will you explain me  ?

     I made a mistake in my explanation.

     Actually, the GND pins of PVDD_X and GVDD are directly connected to the common ground without a Rsense. Three GND_Xs are connected at a point( juction A), and then connected to the common ground through a Rsense.  My ckt is basically same with the schematic example of the datasheet except the IS_x.

    The power of MCU is separated from the other powers(PVDD, GVDD), and digital isolator are used to transmit  control signals to the DRV8312.

       

     

  • Hi Seewong,

    I don't understand the meaning of "current through the DRV8332 control logic". Will you explain me ?

    >> The original description of the connection included all grounds of the device. That meant any current flowing through the device would be seen in the shunt resistor. Since you have modified the description, the question no longer applies.

    Actually, the GND pins of PVDD_X and GVDD are directly connected to the common ground without a Rsense. Three GND_Xs are connected at a point( juction A), and then connected to the common ground through a Rsense. My ckt is basically same with the schematic example of the datasheet except the IS_x.

    >> The new description is commonly used. There should be no issues with this connection, as long as the voltages requirements are met.