Shorting Power Supply immediately after disconnecting bad?

[skillz21]

I have a DC-DC boost converter board. When I have it at higher voltages and connect a heavy load (or accidentally short the output) sparks appear. If I disconnect the input power, then immediately short the output, the voltage from the capacitors still produces some sparks. Will me shorting the output straight after disconnecting the input, damage the board in any way?

[mvs]

Boost topology does not provide any current limiting in case of short circuit at the output. If high current capable source is connected to the input you may damage diode, pcb traces or inductor. If input is disconnected, it is not that wild, caps may withstand such abuse many times. But there is no reason to do it intentionally. If you do need to discharge capacitors use some load (resistor, light bulb, etc.) with higher resistance then 0 Ohm.

[rstofer]

Remember, the current is related to the change in voltage per unit time or I = C dv/dt.   dv/dt is the change in voltage per unit time and C is the capacitance in Farads.  Suppose you discharge a 100 ufd capacitor from 12V to 0V in 1 microsecond. Then dv/dt = 12/0.000001 or 12,000,000 volts per second.  Multiply by 0.0001 Farads and you get I = 1200 Amps.

Shorting capacitors is a really bad idea.  A 100 ufd is a pretty small capacitor, how about 3500 ufd?  That would give you 35 times as much current or 42,000 Amps.  That should light things up!  Briefly...

There may be some internal resistance that tends to limit the current and it might be worth considering but, basically, those arcs and sparks are a bad thing.