I’ve updated the original post. In any case, the question still stands - would at least like to find more available options, and understand why the ASMedia ones aren’t available.
As other have mentioned, what you got is fine for most basic applications. If you use a polygon pour you can decrease the resistance of the trace and consolidate it all into one large trace. I also see you using traces for ground, the general rule is if you have the room, make all the unused space on at least one of your layers ground with a polygon pour. This makes connecting ground easier, makes your ground more reliable (decreased resistance) and makes your board less susceptible to external noise
If it’s for a digital or power-electronics design, you might want to bypass that question entirely and put in a plane/copper pour/copper fill (all synonyms) that encompasses all these pads.
This helps with power dissipation and lowers resistance though has parasitic inductance and capacitance ramifications. It depends on what goes through that net !
On the other hand if this is analog, high frequency, rf or mixed-signal, I would suggest looking at what kind of requirements you have for that net mathematically. You can find the parasitic inductance and capacitance equations (approximations) online quite easily.
Why not just connect all the resistors together with one straight trace, and put on trace between that and the cap. They’ll save copper and make the board cheaper.
I know of no PCB fab house that prices production on how much copper is etched out of the foil (even though they recycle the dissolved copper afterwards). On the contrary, i usually got the advice of leaving as much copper on the board as I could, as it makes their life easier (and balancing becomes very easy).
Would they really? I made only one PCB so far, but there your price was independent of design. I also don’t think they save a significant amount of copper either way. Would they notice at all? When you etch away the copper from your PCB you would need to measure how much copper your etchant took in and I would imagine that’s not worth the effort. Feel free to correct me if I’m wrong though.
Seems your linked website as a very believable conclusion attached to it. I have a similar issue where the relay module would behave erratically. In my case it was when the relay module/595 chips received power before the Arduino was fully powered up. It’s unlikely that a load affects your relay module as they should never be connected to the main circuit.
I guess something like a pulldown resistor on the SER, CLK and RCLK pins would solve the issue since that would kill any noise. The noise is probably the kind of voltage that BARELY registers as HIGH but highly random.
That or making the relay module only turn on after the microcontroller has finished starting up using a mosfet or something.
Well, for #2, there are excellent modules based on the TP4056 that cost 1$. They charge lithium-ion batteries only. So check the label (yes, I know it clearly says Li-ion but don't trust strangers on the internet for safety facing stuff...), if it says Li-ion, then these are great.
For #1, probably one of those fat traces in the flexible cable is BAT+ and the other is BAT-. I would look for a way to safely remove the plastic coating in such a way that I can't accidentally short circuit it. For example, exposing the copper for BAT+ on one side, and BAT- on the other.
I would just use a MOSFET and resistor to drive the LED if you are only using it in short bursts.
If you want to drive the MOSFET directly from the microcontroller pin, it will need a series resistor to limit the current since the gate has quite a bit of capacitance. If your microcontroller pins can handle 15-20mA, it will be able to switch an AO3400A fast enough without needing a gate driver.
Hey, thanks for your comment. I looked at using a resistor in series with the LED, but if my calculations were correct I could only power the LED less than 3W and 2W would be wasted.
Since the remote control signals are short and low duty cycle, you could use a capacitor to provide the peak current for the LED without going over the maximum current of the power supply.
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.
Hey, thanks for your comment. I’ll look into the MAX16834 as soon as I have time tomorrow. Also, how would I be able to use a constant current driver with shunt dimming? How would I go about calculating the time a constant current source takes to recover from a short?
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.
If it’s a high-current, high-frequency, or low-noise circuit then maybe the inductance or resistance of those traces would matter, but they’re very short so probably not.
If you’re mass-producing it, then sometimes the reflow or wave solder process works better if the traces leave the pads in particular ways. You’d talk to your manufacturer about this.
If this is a hobby project, you’re overthinking it; arrange them in a way that pleases you!
There is a couple of things I would suggest looking into. First just make sure the LED strip still works, then try a adding a current limiting resistor to the strip, even if it already has one it could help. A unity gain buffer could help as well. I also noticed that there is no active regulator on it, and all the work is put on a zener so I would also say either jank in an active regulator or even easier, supply it with a regulated rail
I would try and find a pinout for the specific battery. The connections will include V+ and V- and then some others like batt temp, and some other diagnostics stuff. I'm not intimately familiar with newer phone batteries, you may or may not be able to get the battery to charge if you dont have the right circuitry
Ideally the logo should be something simple, because it gets displayed in many different places and usually pretty small. ~500x500px should be enough, and the main content should be inside a circle, because the corners are often not displayed.
A more detailed artwork is better for the bigger banner. Most communities seem to use something around 2000x1000px or so.
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