r5452 - trunk/gta02-core/docs/ecn

[werner at docs.openmoko.org]

Author: werner
Date: 2009-08-15 12:58:52 +0200 (Sat, 15 Aug 2009)
New Revision: 5452

Modified:
   trunk/gta02-core/docs/ecn/ecn0014.txt
Log:
- ecn0014: clean up VBAT and discuss naming of nUSB_OC net



Modified: trunk/gta02-core/docs/ecn/ecn0014.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0014.txt	2009-08-15 10:33:57 UTC (rev 5451)
+++ trunk/gta02-core/docs/ecn/ecn0014.txt	2009-08-15 10:58:52 UTC (rev 5452)
@@ -13,6 +13,19 @@
 Joerg Reisenweber has designed a circuit using the BQ24314DSG:
 ecn0014/U4905-circuit.png
 
+Based on further comments from Joerg:
+
+VBAT overvoltage checking is not really used in this scenario.
+According to the BQ24314 data sheet:
+
+| If the Bat-OVP function is not required, the VBAT pin should be
+| connected to VSS.
+
+Therefore, R4903 should be removed and VBAT connected to GND.
+Also, nUSB_OC is a bit mis-named since there should never be an
+overcurrent condition (barring catastrophic PMU failure.) nUSB_OV
+would describe its function more accurately.
+
 Defer this to post-gta02-core since it requires a new part and it's
 not an emergency.