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Original question:

DRV8300: The maximum driven current

DRV8300: Gate drive current limiting feature of DRV8300, circuit design with it

Rohit Thomas
Prodigy 20 points
Part Number: DRV8300

Hi,

So wanted to understand the min and max limits indicated in the datasheet of DRV8300, whether the gate driver inherently has current limiting feature as mentioned for the IDRIVE Implementation of the Smart Gate driver series. As I understand the variation is quite significant, noted in the datasheet - highlighted in the attached image, and is dependent on the temperature from -50 to 150 deg C.

I wanted to understand should the Gate circuit be designed considering this min values for the safe and reliable operating of the Gate driver or since it has the current limiting IDRIVE implemented, we could consider the typical values itself for the same ?

Interestingly it is noted that in typical gate drivers designing based on the gate driver output current limit is highlighted in the recommended operating and that violating which would lead to damage to the device.
In DRV8300

  • 0
    TI__Expert 8421 points

    Hi Rohit,

    Thank you for using our forum! 

    The min/max spec is essentially the most expected extremes within normal operation, as you said. So when designing your system, the "typical" value should be the basis. Unless you expect the device to be consistently operating in extreme circumstances, I would not recommend designing the entire typical system around a minimum or maximum spec, but it is always good to be aware of the reasonable limits in case the IDRIVE value tends to the lower or higher side occasionally. 

    I recommend characterizing you power stage to determine how close your normal operating condition is to the "typical" spec if possible.

    Please let me know if I can clarify or help further.

    Best Regards,

    -Joshua

  • 0 in reply to Joshua Maize
    Prodigy 20 points

    Hey Joshua,

    Thanks for replying to the query, so the idea is to design the system around the typical values only as you have pointed out. 

    The concern was with respect to the somewhat significant variation, almost half, from the typical values 400mA to 750mA (typ) and 850mA to 1500mA (typ). The worst case operating temperature for the power stage would be about 100 deg, typically about 60-70 deg but without the graph of the temperature vs peak gate current it would be difficult to understand the design margin the system would have, right ? Could you advice on this, please ?

    Also as I have mentioned, was wondering about the current limiting of the terminology - IDRIVE (as from smart gate driver) in this Gate driver DRV8300 ? why this different way of representation with respect to typical gate drivers, also why this, if a critical parameter is not highlighted in the datasheet in the recommended operating conditions ?

    Thanks & Regards,

    Rohit..

  • 0 in reply to Rohit Thomas
    TI__Expert 8421 points

    Hi Rohit,  

    Thanks for the extra clarification.

    Let me look nto the matter a bit more to better answer your questions!  I'll have a response/suggestion for you ready as soon as I can this week. 

    Best Regards, 

    -Joshua

  • 0 in reply to Joshua Maize
    TI__Expert 8421 points

    Hi Rohit,

    Sorry for the delay. I will respond with a further update before the end of the week. 

    Best Regards,

    -Joshua

  • 0 in reply to Joshua Maize
    TI__Expert 8421 points

    Hi Rohit, 

    Rohit Thomas said:
    The concern was with respect to the somewhat significant variation, almost half, from the typical values 400mA to 750mA (typ) and 850mA to 1500mA (typ). The worst case operating temperature for the power stage would be about 100 deg, typically about 60-70 deg but without the graph of the temperature vs peak gate current it would be difficult to understand the design margin the system would have, right ? Could you advice on this, please ?

    Every device will have variation of these values due to the nature of IC architecture, so characterization of your system is a must. Yes there is no graph of IDRIVE performance over temperature range for this device, but higher temperatures typically lead to lower IDRIVE values. A starting place to best understand your device is to bench test its nominal value and determine where it sits in the 400-1200mA range.

    Once again, the min/max values are the absolute variance across device/temp/operating condition, and may never be reached or approached. 

    Rohit Thomas said:
    Also as I have mentioned, was wondering about the current limiting of the terminology - IDRIVE (as from smart gate driver) in this Gate driver DRV8300 ? why this different way of representation with respect to typical gate drivers, also why this, if a critical parameter is not highlighted in the datasheet in the recommended operating conditions ?

    IDRIVE does not limit current, but allows different specified amounts to flow based on the designed device architecture. You can not operate outside of the specified IDRIVE current range since this is a setting inherent to the device, if I am understanding your question correctly. This app note here will better help understand the terminology and operation of Smart Gate Drive.

    Best Regards,

    -Joshua

  • 0 in reply to Joshua Maize
    Prodigy 20 points

    Thanks Joshua for clarifying.