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Gate Driver IC's

rosc_4806121
New Contributor

I am doing a new design with the 1ED44173N01B gate driver chip.

In testing the design I can see 0.8+ volts on the OCP pin but there is no Fault driven.

If I bring the Fault line down externally the output goes off (as I would expect).  But high current across the sense resistor (with a voltage at the OCP pin of 0.8V does not trigger the Fault?

I am sure I am missing something here.

Attached is a picture of the circuit in question

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1 Solution
Abhilash_P
Moderator
Moderator

Hi,

 

    According to the product 1ED44173N01B datasheet and spec, it has a function of over current protection with a threshold VCSTH at the OCP pin input. The voltage at this pin is the negative voltage drop sensed across the system current sense resistor. After blanking time of tBLK and the voltage of OCP pin is over VCSTH, the 1ED44173N01B causes fault logic to initiate a fault shutdown sequence. This sequence starts with the generation of a fault signal and internal MOSFET QFLT is turned on and EN/FLT pin is pulled down. 

The minimum value or the threshold value that is VCSTH is -0.246V. But the voltage at the OCP pin that you are getting is +0.8V. Hence the fault is not getting sensed and tripped.

Please connect the sense resistor in the GND path as shown in the below image for proper sensing and functioning of the gate driver circuit.

Abhilash_P_0-1635247807349.png

 

 

Please let me know if you were able to solve the issue.

 

 

Regards,

Abhilash P

 

 

 

View solution in original post

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1 Reply
Abhilash_P
Moderator
Moderator

Hi,

 

    According to the product 1ED44173N01B datasheet and spec, it has a function of over current protection with a threshold VCSTH at the OCP pin input. The voltage at this pin is the negative voltage drop sensed across the system current sense resistor. After blanking time of tBLK and the voltage of OCP pin is over VCSTH, the 1ED44173N01B causes fault logic to initiate a fault shutdown sequence. This sequence starts with the generation of a fault signal and internal MOSFET QFLT is turned on and EN/FLT pin is pulled down. 

The minimum value or the threshold value that is VCSTH is -0.246V. But the voltage at the OCP pin that you are getting is +0.8V. Hence the fault is not getting sensed and tripped.

Please connect the sense resistor in the GND path as shown in the below image for proper sensing and functioning of the gate driver circuit.

Abhilash_P_0-1635247807349.png

 

 

Please let me know if you were able to solve the issue.

 

 

Regards,

Abhilash P

 

 

 

View solution in original post

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