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  • TI Thinks Resolved

DRV8873: DRV8873HPWPRQ1

Prodigy 125 points

Replies: 6

Views: 125

Part Number: DRV8873

Hi,

I am looking for a design alternate for H-Bridge Driver IC VN771KPTR-E of ST Micro make. While exploring TI alternatives, I could come across DRV8873HPWPRQ1 as a replacement.

Is this device meant for only brushed DC motors?

Thanks and Regards,

Subramaniam

  • Hi Subramaniam,

    The DRV8873HPWPRQ1 (and any brushed DC driver) can drive other inductive loads like relays, solenoids, and single phase electrically commutated motors.

    Rick Duncan
    Motor Applications Team

  • In reply to Rick Duncan:

    Dear Rick,

    While a brisk walkthrough on the datasheet for DRV8873HPWPRQ1, reveals a recommendation for SRC pin to be tied to GND. Whereas in our design requirement we are seeking a separate Return path for the VM driving 28V controlled from a backplane interface by an external processor board.

    So tying this to return path through a backplane requires trace connection in backplane. Whereas in datasheet recommendation it is mentioned to tie to GND through.

    Does the device provide isolation between SRC and GND and PPAD pins internally?

    Attaching implementation scheme as per recommended application circuit reference. Request you to confirm if it is ok to implement with DRV8873H replacing VN771K.

    Thanks and Regards,HBridge_V02.pdfHBridge_V02.pdf

    Subramaniam

  • Part Number: DRV8873

    Hi,

    Seeking replacement for VN771KE device from TI I came across DRV8873HPWPRQ14188.HBridge_V02.pdf

    Refering datasheet for DRV8873HPWPRQ1, reveals a recommendation for SRC pin to be tied to GND. Whereas in our design requirement we are seeking a separate Return path for the VM driving 28V controlled from a backplane interface by an external processor board.

    So tying this to return path through a backplane requires trace connection in backplane. Whereas in datasheet recommendation it is mentioned to tie to GND through.

    Does the device provide isolation between SRC and GND and PPAD pins internally?

    Attaching implementation scheme as per recommended application circuit reference. Request you to confirm if it is ok to implement with DRV8873H replacing VN771K.

    Thanks and Regards,

    Subramaniam

  • In reply to Subramaniam NS:

    Hi Subramaniam,

    The DRV8873HPWPRQ1 does not provide isolation between SRC and GND and PPAD internally.

    The DRV8873HPWPRQ1 should work for the application shown. There are a few followup questions, such as:
    1) What are the motor specifications?
    2) Do you intend to regulate the current using IPROPI?
    3) What signals are provided at IN1 and IN2?

    Rick Duncan
    Motor Applications Team

  • In reply to Rick Duncan:

    Hi Rick,

    We are looking to incorporate DRV8873H-Q1 in the design. Hereunder response to your queries.

    Please find attached motor specification document. 

    For IPROPI there is no analog sensing available on the board. Is there any method to control the motor load current (Current limit threshold (itrip)) in hardware version of H-Bridge component, as required for the various specified motors? 

    IN1 and IN2 are driven by CPLD IO which are exclusive bit high and bit low. One bit to open the valve and other bit to close the valve. 

    With our hardwired device’s nFAULT , we will be able decipher open load fault condition, other fault conditions of under voltage, overcurrent, thermal status cannot be detected exclusively using this device. How to differentiate the internal fault conditions apart from open load.

    I suppose nOL should be enough to detect open load condition and there is no need to maintain with external hardware VOLA as mentioned in page 7 of the datasheet. Please elaborate.

    Please provide your email contact so as to have our prelim phase evaluation discussions with this component to continue.MotorReqt_V1.docx

    Regards,

    Subramaniam

  • In reply to Subramaniam NS:

    Hi Subramaniam,


    For IPROPI there is no analog sensing available on the board. Is there any method to control the motor load current (Current limit threshold (itrip)) in hardware version of H-Bridge component, as required for the various specified motors? 

    IN1 and IN2 are driven by CPLD IO which are exclusive bit high and bit low. One bit to open the valve and other bit to close the valve. 


    Can you confirm motor 4 is really 7.5A? All others are less than 2A, so this appears to be a typo.

    The two IPROPIx pins can be combined since you are only using one high side. The voltage at the IPROPIx pins can then be fed into a comparator to determine when the current should be regulated. The regulation can be performed by the mcu, or by adding some external logic to gate the input and create a delay before re-enabling the outputs.

    With our hardwired device’s nFAULT , we will be able decipher open load fault condition, other fault conditions of under voltage, overcurrent, thermal status cannot be detected exclusively using this device. How to differentiate the internal fault conditions apart from open load.


    This could be difficult because undervoltage could also include charge pump undervoltage, and thermal status includes both a thermal warning and thermal shutdown. So to determine the fault requires additional information, such as determining if the outputs are active or become active after the fault.

    Please refer to Table 13 for all fault responses. 

     

    I suppose nOL should be enough to detect open load condition and there is no need to maintain with external hardware VOLA as mentioned in page 7 of the datasheet. Please elaborate.


    Open Load can be detected when the device is powered up or exits sleep mode with the outputs disabled.

    I will make arrangements to contact you.

     

    Rick Duncan
    Motor Applications Team

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