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Background: I have a fair understanding of electronics, but it’s clear to me the best way to select an dimming LED driver that will minimize flicker, particularly at low dimming levels.
I understand that in general dimming is accomplished via PWM, and that higher modulation rates allow lower dimming levels with minimal sensible flicker, but modulation frequency doesn’t seem to be a filterable feature, and I rarely see it in spec sheets.
Also, I wonder how does this relate to the loading vs capacity- a load that is near driver capacity vs a load that is a small fraction of driver capacity?
And does constant current vs constant voltage play into this?
Thanks VERY much for any thoughts or guidance of any kind
Since flicker is the primary concern, a two-stage, flicker-free LED driver is typically the best option. An example of this is the EPtronics LP25W series, which is specifically marketed as flicker-free per the datasheet:
Unfortunately, “two-stage” or “flicker-free” driver architecture is not currently a searchable attribute on the DigiKey website, so identifying these products usually requires reviewing each datasheets directly.
Maybe another community member provide additional insight into your other questions.
Unfortunately there are few means to this end that don’t boil down to evaluating candidate units after narrowing the selection range on the basis of other considerations.
There are many technical routes to the same end of a dimmable LED-based light source, with different peculiarities, quirks, and adaptations for different circumstances. Some solutions may deliver different results depending on how they’re used; this example is said to accommodate 3 different styles of control input, and it’s seems likely that one’s choice of PWM signal would translate rather directly into the output.
The “capacity” question might warrant some clarification, from the standpoint of needing to separate the concept of “load” as a thing dependent on a dimming setting, versus two devices both operating at full “on” but nearer one end or the other of their output compliance range. I generally wouldn’t expect much difference in the latter case as long as things are properly applied within their operating limits.
No reliable difference between CC or CV sources in terms of flicker performance; it mostly depends on what route the manufacturer took to reach the destination. Though for the most part one usually only encounters constant voltage LED drivers in context of things like cut-to-length flex strips of this sort that are self-ballasted. They’re not particularly linear in their V-I characteristic, so any dimming option in devices of the sort is perhaps more likely to rely on chopping things up in time and likely to be flicker-prone.
