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DRV593: The output current issue for DRV593

Mickey Zhang
Genius 12080 points
Part Number: DRV593

Hi team,

The customer is using DRV593. His schematic is in the attach. VIN- is fixed 2.5V.  According to the Equation 10 that is on 

page 16 of the datasheet, when VIN+ is 0.4V, the output voltage is 4.61V. The output current cannot be reached to 3A.

When the output voltage is 1V, the output current can be reached to 3A. In his application, the max output power is only 5W.

FAULT1 and FAULT0 are both high level when the output voltage is 4.61V.

Would you check this issue?

DRV593_sch.pdf

Best Wishes,
Mickey Zhang
Asia Customer Support Center
Texas Instruments

  • 0
    TI__Mastermind 24835 points

    Hi Micky,

    When you outputing 4.61V voltage, how much is the load resistance please? You mentioned that 'The output current cannot be reached to 3A', what happen if the output current is close to 3A?(any fault occurs?) If there is no OC or OT fault, how much is the output power in this case? If the output current is below the OC THR and there is no OC FAULT, please check whether there is OT FAULT.

    Best regards,

    Shawn Zheng

  • 0 in reply to Shawn Zheng
    Prodigy 20 points
    how much is the load res ? we used the Load device voltage and resistance set,we can set different resistance,when the output 4.61V,we set the resistance is 2 ohm,the output voltage and current is miss,the output voltage is 0V,and current close to 0 A,the fault0/1 also is high 5V.our output power want is 4.61V,3A in this case.
  • 0 in reply to LEI WANG
    TI__Mastermind 24835 points
    Hi Lei,
    So when you applied 2V signal on input and expect 4.6V output voltage on 2Ohm load. There is actually no OC or OT or UV FAULT on the device, but the output voltage is 0V. Is my understanding correct? How much is the input signal frequency? In this case, did you measure the PVDD voltage and SHUNTDOWN voltage? What if you lower the input signal amplitude? Could you please show me your SCH?
    Best regards,
    Shawn Zheng
  • 0 in reply to Shawn Zheng
    Prodigy 20 points
    Hi Shawn：
    you understand is right，you can see the top of the page Mickey Zhang has upload this part schematic，the PVDD is ok，because of we use the load device（the load resistance can change by set），at first we set DR593 output voltage，and see the load device show reach our setting voltage，and second we set the load resistance to 2 ohm，and last add our load device to the output circuit，but this time the load device show the voltage and current is close to 0，when we set the output voltage is 0.5V，the current can reach 3A，but this is not our aim.
  • 0 in reply to LEI WANG
    TI__Mastermind 24835 points
    Hi Lei,
    You can't connect/disconnect the load when the device is outputting power. Please try to set both INN and INP to 2.5V, then connect the 2Ohm load to the output. Power up the device and adapt INP to 0.5V, then measure the output voltage on the load. It's suppose to be around 4.6V. I replicated this experiment on DRV593 EVM and the result is expected.
    Best regards,
    Shawn Zheng