diff pirelli/chg-circuit @ 387:f190b78c3b6a

pirelli/chg-circuit: found PCHG and the precharge circuit
author Mychaela Falconia <falcon@freecalypso.org>
date Wed, 23 Mar 2022 21:20:26 +0000
parents 8d19e61d202f
children b99663e66660
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line diff
--- a/pirelli/chg-circuit	Wed Mar 23 20:06:08 2022 +0000
+++ b/pirelli/chg-circuit	Wed Mar 23 21:20:26 2022 +0000
@@ -60,3 +60,14 @@
 
 The via hole on L7 at (5631,1250) appears to be an inner via after all: let's
 look for it on other layers.  Couldn't find any connections.
+
+Let's try tracing PCHG (ball B5) from Iota: it goes through a 2-pad component
+(probably the precharge current limiting resistor) centered at (2862,1443) and
+then to a microvia at (2849,1378).  On the populated pic, the 2-pad component
+is indeed a black resistor, marked "470".  Tracing the microvia from L1 at
+(2849,1378): it goes to an inner via at (2865,1350).  Found it on L4: goes to
+another inner via at (5548,1198).  Looking for the new via: found it on L5, goes
+to another via at (5593,717).  Looking for the new via at (5593,717): found it
+on L7, microvia to L8 at (5514,741).  On L8 the microvia lies in the polygon
+that connects the drain output of the P-MOSFET to the anode of the Schottky
+diode, matching TI's reference charging circuit.