Re: [NTLK] Usb powered MessagePad

From: Adriano (adriano.angelillis_at_gmail.com)
Date: Thu May 05 2005 - 12:14:43 PDT


Il giorno 05/mag/05, alle 20:43, Newton ha scritto:

You might add a small DC to DC converter to get the 5V up to 7.5V.
Maybe =
you
can just order one with the right pre-setting or maybe there is a 5 to =
6V
converter available? Only 100mA are needed to operate the Newton and =
since
USB may drive 500mA I could imagine an USB charger too.

First, thansk very much for sharing your idea,
i really appreciate that.

Then you are right, a converter could do the trick,
but as you know, having it completely secure on a MessagePad is a
different story.
At 5V, a 400mA minimum current is needed for powering the mainboard
only,
less than 400mA will damage the Newton,
this why NewtAC need to be used with a powered usb hub only,
cause a non-powered usb hub will share the usb 500mA in 4,
for a total of 125mA per port.

MP1x0 series have different specs, so their chargers were at 7V - 500mA
and charged very well,
and those chargers although a bit slowly, work well on MP2x0 series too.

In theory,
[and staying on my personal experience/tests]
at 5 volts the current will need to start at least at 1.0 A
but need to stay between 1.2 and 1.3 A to fully recharge the MP2k
internal battery.
Out of these current parameters, the Newton will fry.

If i am wrong, please correct me.

Kind regards,

Adriano

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