Overload Protection
This little circuit should save you frying too many of your prototypes when an
unwanted short appears somewhere. At power up, the 10K, 22nF RC combination
presets the latch output to high, hence presenting full power to the load, via
the enhancement mode MOSFET (which ideally should have as low on-resistance as
possible. When the load current exceeds a certain value, as determined by the
value of the potential divider resistor pair (4.7K/1K), the comparator output
goes high and clocks in the low value at the latch Data input. The LEDs will
show if power is being presented to the load.
Before anyone castigates us for using the wrong symbol for the MOSFET, its the
only one that's available in our cheap schematic package.!
Pspice simulation below.
A pcb hasn't been tracked out for this. Play with at your own risk !
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