Power Via Usb

[rixed]

The topic says it all : while coding, the gp2x is continuously plugged into a USB port, so I think it should be cool if the gp2x could then drag it's power from this power supply, like any USB gadgets. So that we could play with it without the need for external power supply or battery set.

So, question for you knoledgeable people that know the internal circuitry of the gp2x : would it be feasable ?

 

[soup_nazi]

Nope, afraid not. Never, ever.

 

[Loubear]

But couldn't you use a usb to ac/dc adapter thingy? Like this...
http://www.newmp3technology.com/proddetail.php?prod=adc

 

[craigix]

GP have a prototype cable which powers ithe gp2x from a PC usb port.

 

[ingrin]

GP have a prototype cable which powers ithe gp2x from a PC usb port.

throuh EXT connection, or through existing USB port, because I didn't think that was possible.

 

[soup_nazi]

Potentially yes, but a usb port only outputs 500mA and the GP2x needs around 1000mA. There are weird cables that source the power out of 2 usb ports, but then you still have the problem of actually connecting your GP2X, so it would take like 3 ports to do it.

There are cables that split off a power plug seperately like the ones used for the PSP, but I don't think you can get a combination of the both...in then end, it's probably easier to buy a psu.

 

[Anhaedra]

Could you do this by soldering wires from the 5V and ground line on the GP2X USB port to the power adapter port? You would need to put a resistor on to bring the USB voltage down from 5V to 3ish volts, too...

 

[soup_nazi]

Could you do this by soldering wires from the 5V and ground line on the GP2X USB port to the power adapter port? You would need to put a resistor on to bring the USB voltage down from 5V to 3ish volts, too...

I suppose you could give it a bash. Keep in mind that the voltage can vay from 5.25V-4.375V. I'd definitely test what you've built with a trusty volt/ameter...

 

[scorpio]

GP have a prototype cable which powers ithe gp2x from a PC usb port.

throuh EXT connection, or through existing USB port, because I didn't think that was possible.

Probably like the PSP and DS USB/charger cables, where it splits off a power connector which will plug into the GP2X power socket beside the USB.

 

[BradN]

Potentially yes, but a usb port only outputs 500mA and the GP2x needs around 1000mA. There are weird cables that source the power out of 2 usb ports, but then you still have the problem of actually connecting your GP2X, so it would take like 3 ports to do it.

Yeah, but you gotta go by watts... USB can put out about 2.5 watts (5V*500mA), which would be around 757mA at 3.3V (assuming perfect conversion), so it's probably possible, and if the internal regulator can handle 5V input efficiently (and without letting out magic smoke), it wouldn't even need any extra circuitry. If they're going to be manufacturing custom cables, they could always put 2 ends on the gp2x side anyway, so only one port would be needed.

Also, someone suggested using a resistor to drop the input voltage... not only would it be really inefficient (resistor absorbs the same fraction of power as the fraction of the voltage it's dropping), but the GP2X doesn't have a constant equivalent resistance to match a resistor with - sitting in the menu would require a larger valued resistor than playing a movie, etc. A switching type regulator is the way to go if one is needed.

 

[Skitzo]

My mobile phone has charges using a mini-usb port.. I don't want to plug my GP2X directly into the wall though, incase it just goes bang.

According to the adaptor, it puts out 850mA at 5V.. that 5V is too much, isn't it?