Hi there,
Going from 50uH to 100uH is actually better for a number of
reasons and only bad really for one reason.
Assuming a continuous circuit design...
For one, you get one half the ripple current which usually means
one half the ripple voltage which is usually desirable. This also
makes it easier for the cap to work because the change in
current is less, which means the ripple current rating for the cap
can be lower which means the cap runs cooler.
The ripple current is easy to picture:
For a 50uH think about a ramp from say 6 amps to 10 amps
for some design, but for a 100uH inductor the ramp would go
from 7 amps to 9 amps (one half the ripple current). This
is usually a good idea and even necessary in some designs.
So with all this good news what could possibly be wrong?
The bad news (which isnt that bad really) is that the efficiency
for a given inductor design is not as good for a value 2x times
as large, because it takes 1.4x more wire and a heavier gauge
or a larger core size which also makes it bigger physically.
So in view of all that and being that you probably dont need
super high efficiency, you have nothing at all to worry about
and everything to GAIN.
There is a catch, but this probably doesnt apply to your
circuit, and that is that if the design is for a discontinuous
circuit then you have to be more careful about the value
of the inductance or else you might accidentally force the
circuit to work in a continuous mode in which case the
circuit theory is different and so the circuit probably wont
work the way you would expect it to.
As i said though, your circuit probably works in a continuous
mode so i wouldnt worry. If you check the output voltage
and it seems to regulate with a reasonable change of load
and maybe input voltage then it's probably a continuous
mode design. Most DC - DC converters are with somewhat
large dc current flowing through the inductor all the time.
You can double check the data sheet most likely and find
out that way too.
If you happen to have a circuit that depends on inductor
timing to set the operating frequency however then the
frequency will end up being lower, which still probably
wont hurt as long as the output cap is correctly sized.