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How stop Micro burning when GND & VCC short circuit?

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SS1_Raptor

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Hello friends

if i short circuit VCC and GND Micro burn . any Micro

VCC = 3.3V
using LM2596 3.3V .

LM2596 Schematic :

LM2596.png

how can i Protection micro from this ?
 

Hi,

If you short circuit VCC and GND, then the supply voltage should be 0V.
--> There is no electrical energy available.
--> Impossible for anything to burn.

So either your description is wrong, or there is something else in your circuit providing energy to kill the micro.

--> please show the complete circuit, and provide a more detailed error description.

Klaus
 
hi ,

Yes you are right

But it seems. The moment after disconnecting the short circuit
The regulator burns the micro
 

O.K. that makes more sense. Presumedly heavy overshoot during over current recovery.

A switching regulator with soft start after overcurrent shutdown would avoid the overshoot. It's difficult to provide an effective protection with TVS diodes, a 3.3V TVS diode has typical clamping voltage > 6V. If your regulator can't guarantee safe supply voltage, you may consider a SCR crowbar.
 
Very likely a recovery overshoot. Do you have access to a digital scope?

Solutions:
-Either a SCR crowbar as discussed previously, which would latch and you'll have to remove the main supply to unlatch it.
-Or replace the controller with one where a soft-start function could be implemented.
 
Or enough decoupling and maybe series choke, that the
supply flyback can just be "soaked up"?

You might like to put a 'scope to the power pin:gnd and
capture a single sweep, to see what you're trying to fix.
 
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