lemmyman

@lemmyman@lemmy.world

This profile is from a federated server and may be incomplete. Browse more on the original instance.

lemmyman,

TI USB controllers and switching supplies are half of my BOMs

lemmyman,

Leonardo da Vinci developed dick realism in the 1500s, prior to that artists were literally retarded

lemmyman,

Yet one more victim of climate change

lemmyman,

Nobody asked your opinion dude

lemmyman,

Do you need to poop and fart?

lemmyman,

This makes me anxious, my kids would absolutely flip both of those pizza boxes and/or stomp on the pizzas with their random limb flailing carelessness

lemmyman,

AI will never crack that one

lemmyman,

Typical Lemmy experience

lemmyman,

Isn’t that Meryl Streep?

Lemmy: fails the vibe check (lemmy.zip)

Zero chill factor. Every post has to have a dissertation under it explaining how its problematic. Reddit/Twitter reposts that make you nod your head in agreement get mindlessly upvoted. Even communities that should be more off-color get relegated to the most normie shit possible. Lemmy feels homogenous as fuck. /rant

lemmyman,

I looked and saw that you’ve posted about 100 times in the last month (many of which j recognized and appreciated, thank you for your service). Three of them have net down votes.

Seems like your posts are mostly well received, so I’m not sure what the issue is? 97% positive isn’t enough?

lemmyman,

courageous convictions will drag this dream to existence

lemmyman,

Take the L

lemmyman,

I imagine something like colonal cavitation. Little sonic booms of intestine collapsing on itself. Probably not healthy

lemmyman,

Finally a reasonable take

lemmyman, (edited )

The nice thing about this style of communication is that it makes the context explicit, so I can at least look up what you’re talking about. You know, when I have access to a means to search the entirety of a civilization’s works.

lemmyman,

Is Cup Day when the guvnas have a cuppa?

lemmyman,

There’s a reason they call it explosive diarrhea

lemmyman,

1989 patent by Stratasys

lemmyman,

I wouldn’t use the PAM2804. The datasheet recommends a PWM frequency of 500 Hz, and if you look at the “PWM Dimming: ILED vs. Duty Cycle” chart on page 5 you can see why - at 1 kHz there is already a significant reduction in the average LED current. The enable response just isn’t fast enough to modulate at 38 kHz - by the time you want to turn it off, it will barely be on.

This isn’t quite enough for your 38 kHz either, but it’s closer (and waaaay more complicated): MAX16834. The datasheet says it can do up to 20 kHz, but at a glance I did not see a particular spec that seems to actually limit that.

Here’s an article about fast switching LEDs. All the linked products unfortunately have supply voltage ratings above yours, so they won’t work. But it discusses the concept of shunt dimming, where you’d end up simply bypassing the current around the LED rather than actually turning off the current regulator. Inefficient, yes.

lemmyman,

How would I go about calculating the time a constant current source takes to recover from a short?

To the extent possible, I’d look for graphs of “load regulation” in the datasheet, which graphically depict the regulator’s response to a load change. But that seems like maybe an uncommon thing for LED drivers (neither of the two parts we’ve been discussing have those in their datasheets).

Alternatively, if the regulator lists its control bandwidth in the datasheet, you could use the old rule of thumb to relate that to the rise time. For instance, if you’re modulating at 38 kHz, and you want to be sure your rise time is less than 10% of a period, you’d want it to be less than 1/380,000 = 2.6 microseconds. From the article, you’d want a control bandwidth of no less than 0.35/2.6 microseconds = 133 kHz. (or you could just say you want a bandwidth at least 3.5x your carrier frequency).

Using that metric, the MAX16834 is more than capable - yet despite that, the datasheet suggests (not a hard spec) that PWM dimming is functional only up to 20 kHz. I don’t know how to explain that discrepancy. This is where I’d buy an eval kit and try it out to see what I’m missing.

  • All
  • Subscribed
  • Moderated
  • Favorites
  • •
  • localhost
  • All magazines
    •
    Loading…
    Loading the web debug toolbar…
    Attempt #