[time-nuts] ULN regulator with more current capability than LT3042?

ed breya eb at telight.com
Wed Mar 21 20:54:32 EDT 2018


Before adding complexity of parallel devices or external passing, why 
not just try the old parallel-resistor trick? If the load takes a 
certain minimum current under all conditions, provide less than that via 
a resistor from the raw source to the regulated output, likewise under 
all conditions. The main regulator will still do its thing, but not have 
to supply all the current. You're just looking to get a little more 
margin between the spec current and actual load. The short-circuit 
current would be increased too, so take that into account.

Now some will say, "what about the ripple voltage from the raw supply 
causing ripple current going right to the output?" Depending on the 
regulator's characteristics, I think it should be able to handle it just 
fine - it's easy enough to hook it up and see how it works.

It would be good have OVP on the output regardless of the regulation 
scheme to protect the load if it's sensitive to OV. Obviously, the 
parallel resistor one could allow the voltage to go high if some load is 
lost, but the same can happen with a regulator failure too.

Ed



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