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Part Number: INA195
I am designing some sort of a low current e-Fuse (10mA threshold) at 600Vdc application. We would like to provide a "test port TP" for service personnel to check the output voltage of High Voltage battery bank (600-800Vdc) using a multimeter and would like to provide some sort of safety disconnect in case of accidental discharge.
I came up with this circuit and would like to know if the INA195 is fast enough to respond for current flowing through Rshunt. With Rshunt=10R, @ 10mA threshold, that will generate 0.1V, with INA195 G=100, its output will be 10V. Through R1 and R2 will generate the 1.24V threshold of the LMV431. When the output of LMV431 is pulled low due to overcurrent at RShunt, Gatedriver UCC27519 will turn off T2 SIC Mosfet. T1 will serve as a latching function to keep UCC27519 input low during the first overcurrent condition.
INA195, LMV431 and UCC27519 will have an Isolated power supply 15VISO, and ISOGND which is connected to the test port TP.
Can you please comment on this?
The question whether INA195 is fast enough to respond for current flowing though Rshunt needs to be answered with the knowledge of your requirement. The output will take roughly 10uS to reach 10V. There are other delays to consider. Therefore if your requirement in on the order of hundreds uS to mS, it is probably OK in terms of timing.
You also want to think though what INA195 sees when T2 is ON. Maybe you omitted other loads in the drawing, but as drawn, the 600V will show up at the “+” input which will be a problem.
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In reply to Guang Zhou:
I understand you concern regarding the 600Vdc being present on IN+ of INA195. My circuit use the similar technique as INA260 TIDA-01590 (see below). The INA260 has common mode range of 0-36V on the IN+ and IN- but still sees the 1200Vdc on the IN+. INA195 has common mode range of -16 to 80V on IN+ and IN-.
There is no load connected to TP. TP is just a Test Port for Multimeter to check output voltage of the battery bank..
In reply to Jean Revan:
Thank you for the clarification, I see it now. Please let me know if further assistance is needed.
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