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DRV8245-Q1: DRV8245-Q1

Samuel Zhang
Prodigy 100 points
Part Number: DRV8245-Q1
Other Parts Discussed in Thread: DRV8714-Q1, DRV8263-Q1, DRV8718-Q1,

Tool/software:

Hello,

Dose TI have integrated H-bridge or full-bridge motor driver circuits that have similar spec at DRV8245-Q1 but also include some sort of Back EMF shunt regulator feature built-in? 

I was looking for something that dose not need digital interface (I2C or SPI) but something that can be controlled by IC only other than input signals control output of the bridge. 

Otherwise, I will have to look into discrete or some sort of analog design to deal with back emf generated by the motor. 

Thanks 

  • 0
    TI__Mastermind 44995 points

    Hi Samuel,

    Thank you for your question.

    Samuel Zhang said:
    Dose TI have integrated H-bridge or full-bridge motor driver circuits that have similar spec at DRV8245-Q1 but also include some sort of Back EMF shunt regulator feature built-in? 

    Please clarify what you meant by back EMF shunt regulator? Do you need this for speed regulation purpose? We have powered off braking in some of our products. The integrated motor driver DRV8263-Q1 (SPI version) and the gate driver DRV8714-Q1 and DRV8718-Q1 SPI and HW version available have this feature. Please review these datasheets. What is the purpose of back EMF shunt regulator in your application? Would this be for motor turn off or address manual movement? 

    Regards, Murugavel  

  • 0 in reply to Murugavel4637
    Prodigy 100 points

    Hello, sorry about the unclear question. 

    I basically want to suppress BEMF to the ground while motor is running. Only purpose is to block this energy flowing back to the source and dissipate through shunt resistor or something. 

    Regards

  • 0 in reply to Samuel Zhang
    TI__Mastermind 44995 points

    Hi Samuel,

    No worries. 

    Samuel Zhang said:
    basically want to suppress BEMF to the ground while motor is running.

    If I understood correctly, this means the motor is being spun by external means mechanically and it generates a BEMF across its terminals, correct.

    When the outputs are active (device awake and DRVOFF = 0) and the input PWM is decreased for example in PH/EN drive mode, the BEMF will be dissipated by both HS-FETs during recirculation conduction. If the PWM input is made 0 instantly this could allow all the BEMF driven current to flow via the HS-FETs and likely exceed overcurrent trip point OCP. When OCP happens the high current flow path would be suddenly broken which may lead to a high voltage across the motor terminals due to inductive kickback that could potentially damage the device. To avoid this situation it is recommended to have a steady ramp down of the PWM duty cycle to 0 from whatever duty cycle that was used for running the motor. 

    It could also be the DRV8245-Q1 stopped driving the motor by turning the outputs HiZ by either nSLEEP or DRVOFF. In this case the BEMF appearing at the OUT1 and 2 would be conducted via the body diodes back to the VM and GND rails. Because the motor is losing energy, the BEMF voltage will never exceed the supply voltage VM. In this case the motor will coast to a halt and its BEMF dissipates slowly and safely without impacting the driver. I hope this helps. Thank you.

    Regards, Murugavel