USB hardisk question

[psnathan]

I recently bought a 2.5" USB2.0 external hardisk case and a 40GB IBM Travelstar hardisk to go along. The case requires external power and came with a PS2 port connector to get the power.

Yesterday, I found that my friend's laptop does not have a PS2 port. So I thought I'll either buy or make a AC to DC adapter to power the hardisk. I measured the PS2 port and found that it gives out 5V. The problem is I don't know how much current the hardisk drains.

So, my question is

1. Does anyone know what is the max current drain a PS2 port can tolerate?..... or

2. Does anyone know how much max current does a IBM Travelstar 40GN (40GB) needs?

Thank You for your time.

 

[HammerBot]

According to the <A HREF="http://www-3.ibm.com/storage/hdd/tech/techlib.nsf/techdocs/C5973B311E40B36D87256B290055562D/$file/T60gh40gn_ds.PDF" target="_new">datasheet</A> it has a peak power consumption of 4.7W (thats 940mA) and a maximum seek power consumption of 2.3W (460 mA). So the power supply should be able to provide 500 mA continuosly and have a large output capacitor to handle the peak power requirements during starup.

<i><b>Engineering is the fine art of making what you want from things you can get</b></i>
<A HREF="http://www.btvillarin.com/phpBB/viewtopic.php?t=655" target="_new">My systems</A>

 

[psnathan]

Thank you HammerBot! I'll try out tomorrow.....Hmm wonder what regulator IC to use. Any suggestion?

 

[HammerBot]

That really depends on what kind of PSU you wish to make and where you get the power from.
If your powersource is 110 or 230 VAC, the easiest will be to buy a prebuild AC-DC adaptor that can provide 5V, 5W. Such one shouldn't cost more than 20 USD.
I would prefer that the HD is powered up at the same time as the PC. Multiple powersources for a system tends to be problematic, and its easy to damage I/O ports. This, however, may be difficult if the PC doesn't have any ports that is capable of supplying the power.

<i><b>Engineering is the fine art of making what you want from things you can get</b></i>
<A HREF="http://www.btvillarin.com/phpBB/viewtopic.php?t=655" target="_new">My systems</A>

 

[Lonemagi]

You could alwas make it drain the xtra power from another USB port right? I have seen a few of those drives with 2 USB plaugs. I have a Torica enclosure myself, and these things are handy. It even works without the extra power, but it is not recommended

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