J
Jon Slaughter
- Jan 1, 1970
- 0
We generally add bypass caps to temporarily supply power to an IC for
various reasons. The only problem with this is that the bypass caps will
also supply power to any other ic's and components around them.
By adding a diode in series with the supply voltage in front of the caps
when can force the power to be supplied only to the IC. This has the effect
of still providing power to the IC and preventing reverse polarity from
damaging the IC(theoretically at least).
But conversely they also do not supply power in a broader region which might
be beneficial. The diodes also cost more and waste power.
I have a board consisting of many LED's and several constant current LED
drivers(with a few other things that are not important for this discussion).
I'm trying to determine if I should add the diodes or not. I am bypassing
the drivers with several caps from 0.1uF to 1uF(since I need packages of 402
because of placement issues). What I'm thinking is that the LED supply is
not as important as the driver supply since if any type of very quick power
dips occur the drivers would be potentially reset while the LED's would just
get dimmer.
I'm not sure if it all really justifies all the diodes though as it might
simply be a waste? The main thing I like about them is that it allows the
bypass caps to only bypass the IC's they are designated for and not end up
supplying LED's which is not important(or as critical).
But of course it could be wasting the caps since in some circumstances maybe
the LED's need more "bypassing" than the IC's yet the diodes prevent this.
I will sprinkle some larger caps across the boards for flavor.
various reasons. The only problem with this is that the bypass caps will
also supply power to any other ic's and components around them.
By adding a diode in series with the supply voltage in front of the caps
when can force the power to be supplied only to the IC. This has the effect
of still providing power to the IC and preventing reverse polarity from
damaging the IC(theoretically at least).
But conversely they also do not supply power in a broader region which might
be beneficial. The diodes also cost more and waste power.
I have a board consisting of many LED's and several constant current LED
drivers(with a few other things that are not important for this discussion).
I'm trying to determine if I should add the diodes or not. I am bypassing
the drivers with several caps from 0.1uF to 1uF(since I need packages of 402
because of placement issues). What I'm thinking is that the LED supply is
not as important as the driver supply since if any type of very quick power
dips occur the drivers would be potentially reset while the LED's would just
get dimmer.
I'm not sure if it all really justifies all the diodes though as it might
simply be a waste? The main thing I like about them is that it allows the
bypass caps to only bypass the IC's they are designated for and not end up
supplying LED's which is not important(or as critical).
But of course it could be wasting the caps since in some circumstances maybe
the LED's need more "bypassing" than the IC's yet the diodes prevent this.
I will sprinkle some larger caps across the boards for flavor.
