ekankjatwani
New Member
View attachment 66439
Hi,
I am working on a design to limit the current in case of short circuit
by the user in one of my ic's. The circuit is shown in the image
below:
So here is my problem:
I simulate the circuit and it does everything as I want. It limits the
current to 200 mA right now. I know I can find better mosfet's which
can tolerate higher collector but no matter what mosfet i choose ,
none of them will be able to tolerate a short. With 30 V and 200 mA
dropping across the Q7 transistor , i am dropping about 6 W. I do not
have enough space in the device design to provide for cooling. I
cannot use a resettable fuse because of the cooling time, no current
limiting diodes because they are rated for too less of a current than
a usual load would require . My last choice would be a microcontroller
trying to sense a voltage across a sense resistor. Please let me know
if you have a better solution to my problem.
Thank You
Hi,
I am working on a design to limit the current in case of short circuit
by the user in one of my ic's. The circuit is shown in the image
below:
So here is my problem:
I simulate the circuit and it does everything as I want. It limits the
current to 200 mA right now. I know I can find better mosfet's which
can tolerate higher collector but no matter what mosfet i choose ,
none of them will be able to tolerate a short. With 30 V and 200 mA
dropping across the Q7 transistor , i am dropping about 6 W. I do not
have enough space in the device design to provide for cooling. I
cannot use a resettable fuse because of the cooling time, no current
limiting diodes because they are rated for too less of a current than
a usual load would require . My last choice would be a microcontroller
trying to sense a voltage across a sense resistor. Please let me know
if you have a better solution to my problem.
Thank You