USB powered — how does it work?

  1. Sinking the voltage chargers when powered?(to be able to judge the max. capacity by drawdown)
  2. As far as I know, the phones suck And 0.5, and more begin to take when contacts close to the data (d+ and d -) and if they break, then that — once the power is limited to 0.5 A?
  3. What if the mains charger is designed for 0.5 or 1A, and to take with him to try more (2 or 3 for example) — it will burn (peregrelsja to a state of depravity) or they should be designed for it?
  4. In network chargers probably rarely the fuses (and if there is, at fault), and the "portable chargers" at what max. current is usually protection? For example, if they are designed for 2A, maybe they are in the current more than 2.1 A already cut off the power?
  5. What max voltage and current for contacts microUSB — what do you think?(by the way, male and female like different resistance)
  6. Do all mobile devices support data transmission while charging? (and by the way, do you know where to buy the hubs for this? to charge the host while connected to a mouse)
July 2nd 19 at 17:36
2 answers
July 2nd 19 at 17:38
1. Yes, sinking. But depends on the scheme of execution and applied wire.
2. Not necessarily a private matter of the producer's standards, this requirement is not described.
3. Nothing will happen, it just will not give more than its nominal value. But burn or no, it depends on the scheme performance and the level of "kitaychiny".
4. You can't take from the source of current is more than he can give. Fuses are to protect from short circuit, from the rest it is not necessary.
5. Please do not use them for purposes not intended for them. 5V/1-2A their nominale. And again, all will depend on what is the quality of the connector - poor contact, for example, that subsidence and heat = failure.
6. Depends on the manufacturer, standards are not described. But most of the support for this does not interfere.
3, 4: Then what's the point of standards to limit taking devices current of a half ampere? - Brandi_Hoppe0 commented on July 2nd 19 at 17:41
2. Ie unknown... - Brandi_Hoppe0 commented on July 2nd 19 at 17:44
5. What do I need to ispolzovatj and what not — it's up to me to decide :)
Power devices is rising, and the micro USB connector is the most popular because it is small. Type-c several times more expensive.
Because the connector is standardized, I don't think there is a difference in width of the male and female contacts. - Brandi_Hoppe0 commented on July 2nd 19 at 17:47
: This restriction does not phone and USB port, and this is described in the standard, the maximum current for USB is 0.5 And 1-2, for USB 3 this parameter is raised to the level to 0.9 And - logan66 commented on July 2nd 19 at 17:50
in the sense of port? Socket and plug or something? No, now that I take through them at 2A. - Brandi_Hoppe0 commented on July 2nd 19 at 17:53
The current limit of USB ports was influenced by the fact that computers, while "hibernation" power to the USB ports is supplied with standby power supply 5V, low-power and it. - logan66 commented on July 2nd 19 at 17:56
takes, but only when the phone santacasa with the operating system, which gives to understand the fact that the computer is turned on. - logan66 commented on July 2nd 19 at 17:59
: I do not understand what does all of this. The question is open (what's the point of standards to limit taking devices current of a half ampere?) - Brandi_Hoppe0 commented on July 2nd 19 at 18:02
I repeat - because the USB standard maximum load is limited to 0.5 A for USB 1-2 and 0.9 A for USB3 - logan66 commented on July 2nd 19 at 18:05

– what's the point limit?
because limited. - Brandi_Hoppe0 commented on July 2nd 19 at 18:08
you so lazy to Google? A limit of 0.5 A at the USB from PC displayed on the basis of the standard. If it requires from the USB port in the PC at a higher current, the port could die. There's also the bus is a low-power management power-in port. Hence the restriction. And in General, when you connect your device with your PC via USB data exchange is on the basis of which the PC finds out what the current will consume the connected device. Read the standards, or something. - valerie.Monahan61 commented on July 2nd 19 at 18:11
>the port can die
From what? - Brandi_Hoppe0 commented on July 2nd 19 at 18:14
>From what?
"Read the standards, or what" (C) + see the scheme of Mat. boards. - logan66 commented on July 2nd 19 at 18:17
: exactly for the same reason that wiring is burnt, calculated on 6A, when it is include welding machine, which consumes 20A. Any circuit designed for a specific power that can pass through the circuit without consequences.
Yes, you can with the charger designed NA3.1A to squeeze even a little more than or equal to 3.1, but you must understand that this is the boundary operation mode with a large heat. For a long time in this mode, the device does not work, alas. - valerie.Monahan61 commented on July 2nd 19 at 18:20
in neighboring response to discuss:
>maximum power supplied to the laptop/computer must be equal to the maximum possible output power of the battery/PSU with the deduction of the maximum possible consumption of a laptop/computer, because usb can connect a large variety of devices, each of which can consume as 0.5 and 1 (ZHD) and 2 (cellphones) ampere — at the same time. - Brandi_Hoppe0 commented on July 2nd 19 at 18:23
: >For a long time in this mode, the device will not work
I think the device should in such cases either to deny food, or must quietly endure the heating from working at max load. - Brandi_Hoppe0 commented on July 2nd 19 at 18:26
:
1 USB however, PC gives 0.5 A (USB2.0) and 0.9 A (USB 3). More from one port to remove do not even try. Moreover, this is the maximum that you can request from USB following the Protocol.
Yes, you can find motherboards with enhanced on-current USB ports, but there will be 4 pieces max.

>> I think that the device should in such cases either to deny food, or must quietly endure the heating from working at max load.
Oh, you are too good opinion about the developers of these devices. I have one of these when the limit current just starts for a second to step out, then return. Do you think it is useful for the same phone? Although the charger is not cheap. - valerie.Monahan61 commented on July 2nd 19 at 18:29
: >on 1 USB however, PC gives 0.5 A (USB2.0) and 0.9 A (USB 3).
Not always.
>this is the maximum that you can request from USB following the Protocol
As stated in the comments to another answer modern computers usually give the maximum current, without waiting for requests.
>you are too good opinion of the developers of these devices
I'm not saying that today all so. - Brandi_Hoppe0 commented on July 2nd 19 at 18:32
:
>>As stated in the comments to another answer modern computers usually give the maximum current, without waiting for requests.
Don't see this assertion in the next branch. Without the consent of the host your device is disconnected from USB when you try to pull more than 100mA.
only if your host supports BC, you can port to pull up to 5A.
Read: https://en.wikipedia.org/wiki/USB#Power there is also a link to the USB standards. - valerie.Monahan61 commented on July 2nd 19 at 18:35
:
>On the standard port should not give more than 100mA without initialization. Manufacturers of motherboards, hubs and other things for a long time it is scored and give the total current that can give. - Brandi_Hoppe0 commented on July 2nd 19 at 18:38
: >only if your host supports BC, you can port to pull up to 5A.
Of course, not only. Manufacturers can produce any current without any standards. I remember the motherboard, ports which offer up to 2A, for example. - Brandi_Hoppe0 commented on July 2nd 19 at 18:41
If the manufacturer puts the screw on standards is not a reason to ditch the standards on their part. Limitations of the current lay not just.
If you are in the port stuck his arm and she agreed to consumption 100mA, then as soon as she flare at the power port will shut down. And if the port it sends to 2A, despite the standard, will burn the first wire from the mouse, for fine. A violation of the standard is a delicate matter in the first place reduces the safety of using. Hope you get it. - valerie.Monahan61 commented on July 2nd 19 at 18:44
if the mouse can Coronati — the problem is the mouse, and not that my computer can anyone supply power to the device without initialization (no d+d-pins). Yes, and I personally I use the device with one port, including findplanet, and eat right and Claudia and Mishka and sometimes something else.
So I would say that security is reduced such that low-quality mouse. We do not complain of the socket for the lack of initialization when the embedded device is short and it turns out a fire. — We are just making a convenient switch at the entrance, cut down (almost) everything, just in case. - Brandi_Hoppe0 commented on July 2nd 19 at 18:47
:
>>if the mouse can Coronati — the problem is in the mouse
A controversial statement. Very.
>>We are just making a convenient switch at the entrance, cut down (almost) everything, just in case.
The standard laid just switch with adjustable current trip. To use,of course, we won't. - valerie.Monahan61 commented on July 2nd 19 at 18:50
: maybe for someone controversial, but I believe that technology should be either short circuit protection or it should be omitted altogether.
>With the standard laid just the switch
But I was talking about a manual switch. For example, you have a lot of USB devices, most of which are not needed when the AFC — so can leaving off the hub with them special. button. - Brandi_Hoppe0 commented on July 2nd 19 at 18:53
:
>>in the technique should be either short circuit protection or it should be omitted altogether
Sad. And what to do in case of overload, which is not technically the fault? To heat the wire until the insulation melts?
>>But I was talking about a manual switch.
But nobody forbids you to tear off the power manually. But the automatic shutdown on excess power would be superfluous. - valerie.Monahan61 commented on July 2nd 19 at 18:56
: >in case of overload
overload what ? the laptop? it needs to cope with it.
>would be superfluous.
overweight it is because it is necessary for the initialization, and it only bothers. - Brandi_Hoppe0 commented on July 2nd 19 at 18:59
You no one is obliged to and should not. There is a standard if it does not suit you - develop & implement your. - logan66 commented on July 2nd 19 at 19:02
: >no one is obliged to and should not
1) what is it ?
2) producers seek to please the customers, and therefore usually give the maximum current.
>There is a standard if it does not suit you - develop & implement your
so he did not follow the above. - Brandi_Hoppe0 commented on July 2nd 19 at 19:05
:
>>overloading of what ? the laptop? it needs to cope with it.
You hellishly smart. Point by point:
let's say your laptop can easily give out to the peripheral USB device up to 5A. If you exceed this current, it uniquely identifies the fault and turns off power to the device.
-you have made a device with a nominal current consumption of about 200mA and powered it from the laptop using the first cable, because such a small current will flow any cable and any USB connector. Of course this cable is not designed for high current.
-your device has become faulty and start to eat 4A because of the breakdown of certain elements. The laptop does not detects the short circuit, since the current limit and power supply it can provide to the port.
Cable overheated, overheated connectors, insulation glass, plastic poddleville.
Cable has shorted out and the laptop to cut down your device, but too late: the fault led to the destruction of at least cable.

And would you limit on port 500mA, would the above not happened. The port would immediately threw the food and Hello.

You could argue that the connected device must have its own fuse, but why? There is a mechanism of intellectual disconnect and should not be further changed and the fuse in the defective device. Reduces the cost of the repair.

>>once it is because it is necessary for the initialization, and it only bothers.
Oh, what the trouble is. You are able to deal with the initialization of the USB device, so it is not needed. Good logic, correct. Approve.

If you need for your device to pull power multiple amps with a voltage of 5V, connect directly to the power bus of the PC, do not force the USB. And if you want power it via USB optimize current consumption, especially since the microUSB is not designed for large currents and notorious QuickCharge does not increase the current and increase the voltage to achieve more power. Already the current is a couple amps well warms the USB connectors. - valerie.Monahan61 commented on July 2nd 19 at 19:08
: >-suppose your laptop can easily give out to the peripheral USB device up to 5A. If you exceed this current, it uniquely identifies the fault and turns off power to the device.
we already discussed it — laptop or identifies the fault and cuts off the power or cope with the load and just does not give more than 5A (or 5.1 A) current. - Brandi_Hoppe0 commented on July 2nd 19 at 19:11
: >but it's too late: the fault led to the destruction of at least cable.
ie fault bad cable is the problem or something ? too small to sacrifice to avoid the convenience of receiving current without initialization. Cables attached to devices sold, burned the device and burned the cable — even in the trash or warranty returns. - Brandi_Hoppe0 commented on July 2nd 19 at 19:14
: >You could argue that the connected device must have its own fuse, but why?
for the convenience of receiving current without initialization and that there was no fault, the device will understand that it exceeds the normal current, and therefore broken and the fuse will work — all in repair. - Brandi_Hoppe0 commented on July 2nd 19 at 19:17
: >You can't deal with the initialization of the USB device, so it is not needed
it is not needed because without it you can do it much cheaper devices powered by USB such as USB fan costs only 50p because it is not initialized. - Brandi_Hoppe0 commented on July 2nd 19 at 19:20
only here because of the fan that cut the other usb device, as it closed the contacts data... - Brandi_Hoppe0 commented on July 2nd 19 at 19:23
: I'm sorry, but you in the development of electronics does not. I think the discussion is over. - valerie.Monahan61 commented on July 2nd 19 at 19:26
their conclusion I consider obvious, may be removed leaving unsubstantiated opinion, to consider it for yourself, I see no reason. - Brandi_Hoppe0 commented on July 2nd 19 at 19:29
July 2nd 19 at 17:40
1. The charger (or any charger with USB host) is sinking when it is taking more current than it can give. In normal mode, the output voltage of the charge is maintained at 5.0 - 5.2 V
But on the other end of the cable is already possible drawdown! The higher the quality of the cables and connectors they use, the less voltage SAG. (because it will not work to squeeze 2A using a bad cable - the voltage will drop, the phone will see it and curbs the appetite)

2+3. USB (up to 2.1 including) requires manufacturers of devices to consume no more than 0.5 A when running. In USB 3.0, the threshold is raised to 1A. Moreover, the USB host is not required to support devices with even consumption 0.5 A - for standard, on initial connection, the device tells you how much amperage it requires to operate, and the host replies, can he provide. According to the standard, upon initialization the device must not consume more than 0.1 A
And here comes in the industry of phones and a standard connector for charging microUSB. When the standard USB is designed for communication, have begun to use "stupid" to provide devices with power, began the confusion. If you connect to PC the phone could "ask" how much current it can give out, "dumb" charging not supported no initialization and connection establishment, and they could take ... and how to learn, how much you can borrow amps from a charger? What is the current consume the phone when stuck 5 volts?? And actually, suddenly it's not a dumb charger, and cable with broken data bus connected to the PC, which can not take more than 0.5 A???
In General, it is invented to check whether the shorted data bus, and if shorted - to take, for example, 1A. Other manufacturers of the same Apple charging was applied on the data bus a specific voltage that the phone was identified, recognized the charge as "a" and consumed, for example, 2A.
Then Qualcomm came up with QuickCharge, made a smart charging let cable instead of 5 volts as much as 9. In the new versions, the voltage increased to 12 at all and then to 20. And all this via USB... something not brought me there. What's the next item?

4. The fuse device I not seen. Usually sags the voltage in volts commercials to four. Such naprugi phone can not take a lot of amps and automatically reduces current consumption.

5. Standard voltage, which theoretically can charge devices in the range 4.0-5.5 volts (I have a charger with 5.5). With QuickCharge 3.0 - voltage up to 20 volts. Depending on the quality of the cable, through it can flow to 2 amps. Well, a maximum of 3, no longer will overheat the contact and all poplavyatsya nafig.

6. In what direction? Charging is generally a side thing in the USB standard. If you're talking about connecting the phone to PC, in which he is charged - usually always works. If OTG on my phone I was able to make sure that he also has been charged. But not always. In this mode according to the USB standard, the phone should serve as a source of power, and not Vice versa, to draw power from attached devices.
1. Okay, so T. O. you can determine the max wattage, it is strange that it does not.
2. "The standard requires" the phrase is hardly correct standard to follow completely, but can be partially, so what's the point to limit the consumption of parampara? ie: "how do you know how much you can borrow amps from a charger?" — why learn?
>According to the standard, upon initialization the device must not consume more than 0.1 A
I.e. mandatory inits.? You can't just stick a fan without d+d-contacts with current take-off 100mah more?(will not work?)
5. The question was not about the cable not about how much it costs to start.
>will overheat the contact
Well, that and we have to figure out how much to spend, so as not to overheat.
6. Well I wrote: to charge the host (the telephone, for example) (Yes, OTG) to connected devices data transmission.
>should serve as a source of power, and not Vice versa
I do not understand that this has to change. In my view, if the voltage in the phone and the connected device are the same, current will not flow, and if connected to more then the current must flow into the phone. - Brandi_Hoppe0 commented on July 2nd 19 at 17:43
1. Not quite. From physics, the dissipation is proportional to the square of the current. It is because increase the voltage, more energy can be transmitted by the same amps (same heat)
2. The USB standard didn't assume that it will be used for charging devices. So as not to damage the terminal equipment, if the phone is not sure that the other end of the charger, it should be the standard, and consumes 0.5 A. If you are sure that your device will not connect to something that can die, if you start to suck a lot of current, make any desired amperage.
What to initialize - it. Standard, the port should not give more than 100mA without initialization. Manufacturers of motherboards, hubs and other things for a long time it is scored and give the total current that can give.
5. High-quality connector and plug is fine pull 2A. More - not worth the risk.
6. It's not communicating vessels. The controller's microUSB port in the phone monitors the status of the connector and the voltage on the contacts. 5 volts is OK, turn on the charge mode, trying to determine who is on the other end, set the desired current consumption. Appeared resistance without naprugi - served 5V, try to initialize OTG device. The phone may not expect that it stuck OTG with power. May include a charging mode, and the device is not recognized. On the contrary, connects the device but will not charge. The behavior is undefined and depends on the specific model. I was able to get the phone to charge when connected to the mouse, but not always. Often he hasn't been charged yet, but the mouse worked. - Brandi_Hoppe0 commented on July 2nd 19 at 17:46
1. What's the dissipation? Talking about how to detect drawdown and "to moderate the appetites" — and it should be done, instead of taking only 0.5 A.
2. >Not to damage the terminal equipment
But 1) in our time are the chargers after all, nothing should be that they take the maximum?
and 2) you can train to do what I wrote above (n. 1) — hardly there at all sources that will deteriorate so quickly?(for a definition of drawdown)
5. I repeat: the Question was not about how much we should or shouldn't start. - Brandi_Hoppe0 commented on July 2nd 19 at 17:49
6. In General, is unknown and depends on the IQ/adaptability of producers. - logan66 commented on July 2nd 19 at 17:52
Took advanced USB multimeter and experimenting with different chargers and ustroystvami. The maximum consumption of the smartphone was 1.3 Ah, charging at 2A not subsided at all, remained at 5.2 V. The low charge dipped to 4.4, the phone continued to consume 0.8 A.
Other device to not increase current consumption by reducing the voltage to 5V. I think it's the most correct behavior is to increase current consumption while charging will not begin squander voltage - Brandi_Hoppe0 commented on July 2nd 19 at 17:55
: charging at 2A not dipped from 1.3 A? Well, it is natural.
>this seems the most correct behavior
I do not think, it is better to take the maximum power, time network the chargers this should not deteriorate as portable (powerbanks) that just won't give up more current than can. - logan66 commented on July 2nd 19 at 17:58
So to determine the maximum that they can give, and the need to monitor the voltage SAG. Otherwise you try to take the 2A from the port that can only be 0.5, the port may be damaged (equal to KZ). - logan66 commented on July 2nd 19 at 18:01
I think that the charger needs to be low quality to burn from that. - Brandi_Hoppe0 commented on July 2nd 19 at 18:04
: You don't have to burn. For example, powerbank are usually turned off in this case. I have a laptop which immediately turns off, if you insert a sample that eats 2 amps (big wire wound resistor with plug). Imagine that a person sticks your device to your laptop, and he puff and dies. - logan66 commented on July 2nd 19 at 18:07
: the problem of the laptop, because it doesn't have to be (and can provide). - Brandi_Hoppe0 commented on July 2nd 19 at 18:10
: Why should not be? And if the flat piece of metal to insert into the USB port? A piece of iron in this situation - the device that "consumes" 30 amps. The usual protection against short circuit. The only difference is the threshold. Somewhere in 2A will pass out somewhere on the 5 - valerie.Monahan61 commented on July 2nd 19 at 18:13
: because usb can connect a large variety of devices, each of which can consume as 0.5 and 1 (ZHD) and 2 (cellphones) ampere — at the same time.
Ie max power supplied to the laptop/computer must be equal to the maximum possible output power of the battery/PSU with the deduction of the maximum possible consumption of a laptop/computer. - Brandi_Hoppe0 commented on July 2nd 19 at 18:16
: And now it is necessary to initialize the USB and the request for the consumption of a particular current. Have not seen the messages like "USB port was disabled due to exceeding of consumption current"? This is the case when the device has requested more than a laptop can give. - logan66 commented on July 2nd 19 at 18:19
: what is "this"?
The laptop can immediately give a max current that many do. - valerie.Monahan61 commented on July 2nd 19 at 18:22
: in order to avoid a situation when the laptop is not able to provide the connected device with power.
no laptop, no charging is usually not regulate the output current. all on the conscience of the device. - Brandi_Hoppe0 commented on July 2nd 19 at 18:25
in such a situation it's okay — the laptop should just shut off the power via USB. - Brandi_Hoppe0 commented on July 2nd 19 at 18:28

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