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Gate Driver ICs Forum Discussions

GaryW
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I am using two 1ED44173N01B driver ICs, each driving their own MOSFET. Both driver ICs are being triggered at the same time and so the MOSFETs are both switched on at the same time. Would it be ok to connect the output pins of the two driver ICs together? The goal would be to ensure the MOSFETs start concurrently as well as to provide a single test point on my small PCB. Thanks!

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GaryW
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Thanks again for the feedback Abhilash. I understand how connecting 2 outputs together is not recommended as they would short VCC to GND if each IC output does not change state at the same time. I still do not see why connecting the 2 input pins together would be a problem, as they are simply logic level gate inputs. We are presently testing to determine an appropriate gate resistor value, thanks for your input. I think we are set, thanks again for your help! -Gary

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Abhilash_P
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Hi,

    Thank you for posting on the Infineon Community.

The gate drivers can be connected in parallel on the output side but not on the input side. For higher drive current requirements, please use a booster circuit on the output side and not paralleling the gate driver on the input side. 

Since you are connecting it on the output side, it is feasible to do it. 

Also can I please know the application circuit. 

 

Regards,

Abhilash P

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GaryW
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Thank you for your reply Abhilash. The attached JPG shows the desired application circuit. As you can see, the EN/FLT pins are isolated from each other, but the IN pins on the input side are connected together. Is this ok?

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Abhilash_P
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Hi Gary,

 

         After going through your schematics, it is recommended not to connect the 2 gate drivers in parallel ( shorting input and output pins )

Few additional points deduced from your schematics that should be taken care of,

  1. Shorting the input of 2 gate drivers will cause short circuit inside the ICs and with time the driver's temperature will increase significantly. 
    Reason: With slight mismatch/delay in the outputs, the respective IC will go into short circuit.
  2. Incorrect selection of gate driver resistance: Considering approximately 2V drop in the VCC path, the current through the gate pin has to be roughly 100A. Which is unrealistic. From the MOSFET datasheet, the preferred gate resistance has to be 4ohms. 
  3. It is recommended to use a single gate driver with the correct specification ( gate drive capability of 2 MOSFETs).

 

 

Regards,
Abhilash P

 

    

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GaryW
Level 1
First solution authored First reply posted First question asked
Level 1

Thanks again for the feedback Abhilash. I understand how connecting 2 outputs together is not recommended as they would short VCC to GND if each IC output does not change state at the same time. I still do not see why connecting the 2 input pins together would be a problem, as they are simply logic level gate inputs. We are presently testing to determine an appropriate gate resistor value, thanks for your input. I think we are set, thanks again for your help! -Gary

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