Hiya,
the charge management datasheet contains all that you need to reverse engineer the iX series charge circuit. It is a pretty good datasheet unlike some
I attach relevant diagrams extracted from the datasheet which may be found here:
http://www.ti.com/lit/ds/symlink/bq24032a.pdfThe bq240xx series charge management IC is a pretty clever design. Here are the highlights......
1. It can tolerate up to 18 Volts on its input so it would not be damaged by the inappropriate use of a 12V adapter (most common over-voltage)
2. The IC automatically takes its supply from either the DC input or the USB socket
3. If neither the DC input nor the USB input have voltage on them, the IC goes into sleep mode whilst maintaining power from the battery to the system that it services.
4. There are two charge state output pins. 'State 1' is the fast charge indicator and 'State 2' is the charge complete indicator. Both are open drain FETS and can sink 15mA.
5. The IC uses a thermistor to measure cell temperature. A 10K NTC thermistor is the most common.
So what can we deduce form the above in your case.
1. It is unlikely that the IC was damaged by an over voltage at the DC input unless it exceeded 18V
2. The two 'State' outputs will be driving the Orange (Fast Charge) and Green (Charge complete) LED's, likely via a separate LED buffer stage to protect the IC from over-current on these outputs.
3. The IC goes into a sleep mode when no voltage is present on either the DC input or USB inputs. The drive to the two 'State' outputs will be removed and both should be off (Open Drain).
4. The Li-Ion cell should have a 10K NTC thermistor present in its package. If a 3rd party cell does not contain the thermistor and associated connections to the plug, it will not be charged.
You really need to take a close look at the drive circuit around the LED charge indicator and check that the two State outputs from the IC go to their 'off' condition when the DC power and USB link is removed from the camera. If they do not go to the off condition, the IC may be faulty or it may be seeing a voltage on its input pins.
I suspect that you will find a simple buffer circuit between the IC and the two LEDs. That buffer circuit may have been exposed to teh over-voltage and a component damaged causing the wierd LED behaviour.
I regret I do not have the spare time to reverse engineer the charge circuit for you. The datasheet will provide a pretty good guide, minus the LED buffer stage (if used). That buffer should be relatively easy to reverse engineer though and I remember a cluster of components near to the LED's so they may be what you are looking for.
NOTE: This IC uses a heat plate in the bottom of its package. It may only be removed safely using a hot air or IR rework station.
Fraser