USB-OVP

[Joerg Reisenweber]

FYI:

From http://www.usb.org/developers/devclass_docs/batt_charging_1_0.zip

-----
Battery Charging
    Specification
         Revision 1.0
          Mar 8, 2007

p.19:
If the current drawn from a USB charger changes suddenly within the range of 
0mA to 500mA, then the
transient voltage from a USB charger shall not go below VCHGR_UNDSHT. Under no 
circumstances shall the
transient voltage of a USB charger exceed VCHGR_OVRSHT.

p.23:
Charger Overshoot Voltage VCHGR_OVRSHT 6.0 V max.
-----

Though we couldn't even attach a USB-charger compliant to this spec, as it has 
to be equipped with micro-USB plug, we should expect to see voltages on 
USB-receptacle of up to 6.0V AT LEAST.

I think it's a strong argument for additional OVP extending our actual 
abs.max.rating of 5.5V to limits safely beyond 6.0V, like we are actually 
about to do for GTA03.

cheers
jOERG
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 194 bytes
Desc: This is a digitally signed message part.
Url : http://lists.openmoko.org/pipermail/hardware/attachments/20080829/ad7b803e/attachment.pgp