[PLUG] Powered USB-A hub - LSUSB MaxPower

[Tomas Kuchta]

On Tue, Jan 17, 2023, 22:16 MC_Sequoia <mcsequoia at protonmail.com> wrote:

> You want to a guess what the MaxPower is listed for the Logitech V20
> portable usb speakers are that are plugged into my pc?
>
> I'll give you one guess.
>
> Yep, MaxPower is listed as 590 mA
>
> "The USB 1.x and 2.0 specifications provide a 5 V supply on a single wire
> to power connected USB devices.
>
> A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. A
> device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0;
> 6 (900 mA) in USB 3.0."
>
> "Bus 003 Device 002: ID 046d:0a04 Logitech, Inc. V20 portable speakers
> (USB powered)
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               1.10
>   bDeviceClass            0
>   bDeviceSubClass         0
>   bDeviceProtocol         0
>   bMaxPacketSize0         8
>   idVendor           0x046d Logitech, Inc.
>   idProduct          0x0a04 V20 portable speakers (USB powered)
>   bcdDevice            0.07
>   iManufacturer           1 Logitech
>   iProduct                2 Logitech USB Speaker
>   iSerial                 0
>   bNumConfigurations      1
>   Configuration Descriptor:
>     bLength                 9
>     bDescriptorType         2
>     wTotalLength       0x00e9
>     bNumInterfaces          3
>     bConfigurationValue     1
>     iConfiguration          3 G6 2005/03/29 10:05
>     bmAttributes         0xc0
>       Self Powered
>     MaxPower              500mA
>
>
> The total RMS Power of the Logitech V20 Portable USB Speakers = 2 W or
> 2000 mA.
> .
>

Yikes, since when 2W at 5V is 2000mA?

-Tomas


>