Smart, right!? Just don't heat it up too much because it can become gooey. If it gets too warm and gooey, you can pick it up with a piece of room temperature piece.
4:25 To record flickering screens you can decrease the camera shutter speed to help smear the frames together. Should work well so long as the cable or camera doesn't move much.
Regarding the debate about connecting GND to Shield, here an elaborate answer: In many cases, connecting shield and GND is not doing much harm, but there are exceptions. Shield acts as EM protection for data wires in the USB cable, for instance. There, you want to have a well defined potential, and GND is a logical choice. On the other hand, when the shield is doing its job properly, then it technically acts as antenna, sending the collected EM noise (AC) to GND when connected. This can influence the GND level when the collected EM noise is strong and/or the components sensitive. Oftentimes, the cables and shielded areas/volumes are small and the components are insensitive, thus, you get away connecting GND and shield. Here is a better way, that covers more use cases: (1) Connect GND to shield with a high Ohm resistor, e.g. 1MOhm. The shield will still be somewhat slowly pulled to GND, thereby the shield fulfilling its role as well-defined potential, but you also effectivel limit the max current exchange between shield and GND. (2) Connect a smaller or medium sized capacitor, e.g. 4.7nF, to shield and GND. This capacitor then acts as filter for high frequencies, so that those frequencies cannot effectively spread into your GND plane.
Wow, thanks for the insights! It also shows that you watched the video carefully because I mentioned this thing towards the end during the kicad session. Thanks! I actually do the 1M resistor solution with all my designs where data transfer is involved. So it seems that it is a good practice.
I think either you want to leave the shield unconnected, or have it at ground potential but a large resistor in between. Because you never want a large current to flow through the shield, which could be touching humans.
What happens when the switch is between 5V and 3V3? Could the 39k2 resistor always be in circuit and just have a 56k8 switch in to select 3V3? I'm sure C8 smooths things out but everything that can go wrong...
Oh wow, this is a great question! I tried it just now. Roughly 80% of the VUSB appears on the output. So yeah, this is not super good. Although I had to set the switch in the middle "very deliberately". It has well-defined endpoints, and it doesn't really want to stay in the middle position. When you switch, even slowly, it is not an issue, but when you intentionally set it in the middle, then that's a problem.
You got a good tip there! It’s good practice any time you’re designing with switches to consider what could happen as the contact moves. Switches can be specified as break-before-make (probably more common) where one contact opens before another one closes. This is particularly risky in a feedback circuit like this one, where feedback will be lost momentarily. The suggested solution of switching in a parallel element is a good one, and the SPST switch required may even be cheaper. A make-before-break switch would do the opposite and briefly connect to both contacts, putting R7 and R8 in parallel. You’d get a lower output voltage momentarily, which is relatively safe, and feedback is maintained. However, that type of switch tends to be less common. You say your switch is relatively well behaved, but you never know when someone might sub in a different part!
Yes! This is a very good tip and I am very grateful for it. It is part of why I publish my stuff: get it peer reviewed, so I can learn from it. In my reviewed design, I have the 5 V resistor always connected and when the user switches to 3.3 V, A parallel resistor gets connected with it.
I now updated all the files on my PCBWay project page according to the suggestion. One little change is that I used an 57k6 resistor because it is a more available value. I did the math and it causes very little difference when it gets connected parallel with the 39k2. The total resistance would be 23k3 instead of 23k2 which would not change the 3.3 V output noticeably. Once again, thanks for pointing it out!
@@british.urchin Yes, I'm not an EE but determinate state is very important in software. I was also thinking that the switch is probably the most failure prone component; being unable to select 3V3 is better than going up near the supply voltage. Given that these would be great for the classroom I'm sure they will get knocked about a bit. I'm happy this suggestion improved the design a little.
Thanks! It is a great idea! I will check this. I guess, it should be powered from the VUSB, so it could create +/-12 or +/-15 V for example. A few capacitors and two LDOs could solve this, but I am not sure how to squeeze it on the board. It would need some redesign probably. Maybe v2.0 will have this feature.
@@CuriousScientist cool. Someone sells one here in canada at a small company but it's never in stock and I know the creator who reviewed it and want it but so many creators are gimme gimme. If you notice alot of channels become glorified review channels. I donate a lot of test gear, game consoles, guitars as I don't believe in hoarding for the sake of it and to share. I gave a ones collection of over 400 games and basically gave them away because it becomes an obsession. So when I get new stuff I donate an old thing. I have this idea that collections own you if you collect for the sake of it. It's part of the reason I'm trying to give away a ton of microcontrollers and components to anyone in North America because shipping from Canada is cheap. I have leds on a level that would make big clive blush hahaha. I have small collections of stuff now like things that have flown on manmade space vehicles and globes. I even have a bunch of guitar pickups and stuff to give away. I have so much hobby grade rc stuff from a business I was going to start that I'd love to trade some of it or give away the used stuff at least. I'd like to sell or trade a seat cushion from the Columbia and Atlantis shuttles that flew 3 missions I paid 500cad for. It flew 3 missions and just shy of 20 million km. I have bills of lading and everything haha. I have an extra brand new lcr meter too I'd like to trade for something and some other meters. If you want a bunch of cool through hole leds and components along with other stuff just gimme a po box if in canada or the us. Otherwise I'd go splits on shipping. I can't fit my guitars in my hobby room anymore and it's a pain in the ass. I spent a year buying every shape and size of led man, I used to send free learning kits to people I'd meet online but most of the gear I have left is premium stuff. I was gonna finish my bench off with a spectrum analyzer but bought a new prs last week instead. Plus the accessories for the siglent model I was gonna buy were half the price of the sa. You can unlock the sa though and dual boot to vna for antenna testing. Both models are identical inside. It can wait till after the rtx5090 comes out now though. Ces in January the blackwell architecture is supposed to drop the day Jenson announces it. I rarely game anymore but I'm a creature of habit since I started university in 98, case and guts upgrade, wait 2 years then gpu. While(True) Haha
@CuriousScientist greatscott did a video where he modified an off the shelf buck pcb to give a negative voltage, could be worth you checking out for inspiration.
I will look at it, but I might not have enough space to add one more buck converter and I cannot use the current one because that's strictly for the 3.3 and 5 V.
As far as I have been able to find out, the shield is connected to ground at the USB host device but not the downstream device. So, in this case, the USB PD charger would be the host and this board would be the downstream.
Then maybe it was not the wisest thing that I did. But I guess it's not too big harm since there's not too much communication going on between the power supply and the adapter.
@@CuriousScientist what about providing jumpers or switches for adding and removing ground-shield resistors and capacitors? Then everyone can test and choose how they want their USB ground and shield connected.
Voltage select part of the circuit is bad designed. You should change it, so that the contact will no disconnect during switching. I.e. one resistor must be connected permanently! The other one should connected in parallel with the first one.
Are there decoys for USB 3.0? I'm trying to get AR glasses powered as a DP ALT display for an SBC that also has power hungry wifi/ble. System works fine as long as I don't try to run it off battery.
Was thinking before to do something like that with USB-C and PD, because I also was very unimpressed with design of the cheap chinese stuff, like even disposable vapes come with USB-C, and they want to sell me breadboard PSU modules with DC Jack like wth bruv? I think there might have been some with USB-C but no PD Tho one thing pls don't use the term "decoy" it's something some china guy got from google translate and it stuck on. It's a PD sink controller.
I think from a perspective that the device pretends to be a legit USB-PD device, we could call it a decoy. But yeah, the chip's 'official' name is a PD sink controller indeed.
The putty for soldering is my new go to now, thanks to you
Smart, right!? Just don't heat it up too much because it can become gooey. If it gets too warm and gooey, you can pick it up with a piece of room temperature piece.
Impressive pick and place skill!
Thanks! A lot of practice and coffee! 😄
@@CuriousScientist coffee/caffeine makes my fingers shaky/tweaking/trembling. I avoid it for such tasks.
Different people react differently.
4:25 To record flickering screens you can decrease the camera shutter speed to help smear the frames together.
Should work well so long as the cable or camera doesn't move much.
Thank you for the suggestion!
Regarding the debate about connecting GND to Shield, here an elaborate answer:
In many cases, connecting shield and GND is not doing much harm, but there are exceptions. Shield acts as EM protection for data wires in the USB cable, for instance. There, you want to have a well defined potential, and GND is a logical choice. On the other hand, when the shield is doing its job properly, then it technically acts as antenna, sending the collected EM noise (AC) to GND when connected. This can influence the GND level when the collected EM noise is strong and/or the components sensitive. Oftentimes, the cables and shielded areas/volumes are small and the components are insensitive, thus, you get away connecting GND and shield.
Here is a better way, that covers more use cases:
(1) Connect GND to shield with a high Ohm resistor, e.g. 1MOhm. The shield will still be somewhat slowly pulled to GND, thereby the shield fulfilling its role as well-defined potential, but you also effectivel limit the max current exchange between shield and GND.
(2) Connect a smaller or medium sized capacitor, e.g. 4.7nF, to shield and GND. This capacitor then acts as filter for high frequencies, so that those frequencies cannot effectively spread into your GND plane.
Wow, thanks for the insights! It also shows that you watched the video carefully because I mentioned this thing towards the end during the kicad session. Thanks! I actually do the 1M resistor solution with all my designs where data transfer is involved. So it seems that it is a good practice.
I think either you want to leave the shield unconnected, or have it at ground potential but a large resistor in between. Because you never want a large current to flow through the shield, which could be touching humans.
Thank you for the good insights! Probably I should add a 1M resistor inbetween then.
What happens when the switch is between 5V and 3V3? Could the 39k2 resistor always be in circuit and just have a 56k8 switch in to select 3V3? I'm sure C8 smooths things out but everything that can go wrong...
Oh wow, this is a great question!
I tried it just now. Roughly 80% of the VUSB appears on the output. So yeah, this is not super good. Although I had to set the switch in the middle "very deliberately". It has well-defined endpoints, and it doesn't really want to stay in the middle position. When you switch, even slowly, it is not an issue, but when you intentionally set it in the middle, then that's a problem.
You got a good tip there! It’s good practice any time you’re designing with switches to consider what could happen as the contact moves.
Switches can be specified as break-before-make (probably more common) where one contact opens before another one closes. This is particularly risky in a feedback circuit like this one, where feedback will be lost momentarily. The suggested solution of switching in a parallel element is a good one, and the SPST switch required may even be cheaper.
A make-before-break switch would do the opposite and briefly connect to both contacts, putting R7 and R8 in parallel. You’d get a lower output voltage momentarily, which is relatively safe, and feedback is maintained. However, that type of switch tends to be less common.
You say your switch is relatively well behaved, but you never know when someone might sub in a different part!
Yes! This is a very good tip and I am very grateful for it. It is part of why I publish my stuff: get it peer reviewed, so I can learn from it. In my reviewed design, I have the 5 V resistor always connected and when the user switches to 3.3 V, A parallel resistor gets connected with it.
I now updated all the files on my PCBWay project page according to the suggestion. One little change is that I used an 57k6 resistor because it is a more available value. I did the math and it causes very little difference when it gets connected parallel with the 39k2. The total resistance would be 23k3 instead of 23k2 which would not change the 3.3 V output noticeably. Once again, thanks for pointing it out!
@@british.urchin Yes, I'm not an EE but determinate state is very important in software. I was also thinking that the switch is probably the most failure prone component; being unable to select 3V3 is better than going up near the supply voltage. Given that these would be great for the classroom I'm sure they will get knocked about a bit.
I'm happy this suggestion improved the design a little.
Awesome project.
Thank you! Cheers!
Dude, these are great.
Awesome job.
(Also, it says USD instead of USB on the back of them)
Wow, thanks for noticing it! I will fix it soon! 😅
I love it. It would be very useful. Unfortunately I don't have the tools (or skills) to do the SMD soldering.
Thanks! You can order the board from my PCBWay project side and get it assembled.
@@CuriousScientist Hmm, I'll look into that and see if it's within my budget! Thanks for the tip!
Positive and negative voltage for opamps would be cool. Still a cool board
Thanks! It is a great idea! I will check this. I guess, it should be powered from the VUSB, so it could create +/-12 or +/-15 V for example. A few capacitors and two LDOs could solve this, but I am not sure how to squeeze it on the board. It would need some redesign probably. Maybe v2.0 will have this feature.
@@CuriousScientist cool. Someone sells one here in canada at a small company but it's never in stock and I know the creator who reviewed it and want it but so many creators are gimme gimme. If you notice alot of channels become glorified review channels. I donate a lot of test gear, game consoles, guitars as I don't believe in hoarding for the sake of it and to share. I gave a ones collection of over 400 games and basically gave them away because it becomes an obsession. So when I get new stuff I donate an old thing.
I have this idea that collections own you if you collect for the sake of it. It's part of the reason I'm trying to give away a ton of microcontrollers and components to anyone in North America because shipping from Canada is cheap. I have leds on a level that would make big clive blush hahaha. I have small collections of stuff now like things that have flown on manmade space vehicles and globes. I even have a bunch of guitar pickups and stuff to give away.
I have so much hobby grade rc stuff from a business I was going to start that I'd love to trade some of it or give away the used stuff at least. I'd like to sell or trade a seat cushion from the Columbia and Atlantis shuttles that flew 3 missions I paid 500cad for. It flew 3 missions and just shy of 20 million km. I have bills of lading and everything haha.
I have an extra brand new lcr meter too I'd like to trade for something and some other meters.
If you want a bunch of cool through hole leds and components along with other stuff just gimme a po box if in canada or the us. Otherwise I'd go splits on shipping. I can't fit my guitars in my hobby room anymore and it's a pain in the ass. I spent a year buying every shape and size of led man, I used to send free learning kits to people I'd meet online but most of the gear I have left is premium stuff. I was gonna finish my bench off with a spectrum analyzer but bought a new prs last week instead. Plus the accessories for the siglent model I was gonna buy were half the price of the sa. You can unlock the sa though and dual boot to vna for antenna testing. Both models are identical inside. It can wait till after the rtx5090 comes out now though. Ces in January the blackwell architecture is supposed to drop the day Jenson announces it. I rarely game anymore but I'm a creature of habit since I started university in 98, case and guts upgrade, wait 2 years then gpu.
While(True)
Haha
@CuriousScientist greatscott did a video where he modified an off the shelf buck pcb to give a negative voltage, could be worth you checking out for inspiration.
Just one more question. What amperage would you expect from the PSU for the opamp?
I will look at it, but I might not have enough space to add one more buck converter and I cannot use the current one because that's strictly for the 3.3 and 5 V.
Thanks a lot, very useful
You're welcome!
As far as I have been able to find out, the shield is connected to ground at the USB host device but not the downstream device. So, in this case, the USB PD charger would be the host and this board would be the downstream.
Then maybe it was not the wisest thing that I did. But I guess it's not too big harm since there's not too much communication going on between the power supply and the adapter.
@@CuriousScientist what about providing jumpers or switches for adding and removing ground-shield resistors and capacitors? Then everyone can test and choose how they want their USB ground and shield connected.
I settled with a 1M resistor between the shield of the connector and the GND plane on the board.
Question if you don’t care about the 3.3 volt would you still need the MP2393GTL-X buck converter?
Yes, because of the high current it can provide. It also has a simple circuit that I can understand.
Voltage select part of the circuit is bad designed. You should change it, so that the contact will no disconnect during switching. I.e. one resistor must be connected permanently! The other one should connected in parallel with the first one.
That's a valid point! I will fix this in the next version!
I'd like to use 28V which is my powerbank capable (PD 3.1). Is there any chip supporting it?
I don't know. I don't know too many PD chips, unfortunately.
PCBWay only offers a PDF file for the schematic. Can we get a KiCAD file?
It's not PCBWay who "offers" it. I only uploaded the PDF. 😉 You can draw it yourself based on the PDF in no time. Cheers!
Are there decoys for USB 3.0? I'm trying to get AR glasses powered as a DP ALT display for an SBC that also has power hungry wifi/ble. System works fine as long as I don't try to run it off battery.
Hi! You mean PD3.0, right? USB 3.0 is a data transfer protocol and not a power delivery protocol.
@@CuriousScientist I think so, yea. I'm a total noob at this stuff.
Then yes, it supports both PD 2.0 and PD 3.0. It is a modern chip.
Alt modes are negotiated over USB PD. However you'll need a programmable PD Controller for it.
small correction. you are saying "Watts" instead of Volts or Voltage
Where?
Was thinking before to do something like that with USB-C and PD, because I also was very unimpressed with design of the cheap chinese stuff, like even disposable vapes come with USB-C, and they want to sell me breadboard PSU modules with DC Jack like wth bruv?
I think there might have been some with USB-C but no PD
Tho one thing pls don't use the term "decoy" it's something some china guy got from google translate and it stuck on.
It's a PD sink controller.
I think from a perspective that the device pretends to be a legit USB-PD device, we could call it a decoy. But yeah, the chip's 'official' name is a PD sink controller indeed.
@@CuriousScientist Your power board is a legit PD device.
For example laptop with USB-C PD input will also use such controller.