Support and General Use > Hardware
iRiver iHP-120/140 USB charge with BQ24022
Sando:
--- Quote from: Davide-NYC on March 30, 2007, 05:17:35 PM ---As long as I didn't plugin both USB and DC in at the same time it should be OK right?
--- End quote ---
If I read the data sheet correctly, the BQ24022 will just charge from DC in if both are plugged in so I believe it'll handle it fine.
Davide-NYC:
OK, I've located the chip in question on the MoBo.
:o (those are some very tiny legs to solder)
I believe I've understood what needs to be connected where and I've generated a little drawing.
Question 1: Is this drawing correct? (I know I could route the wires better)
Question 2: What would the R and C values be?
Question 3: Are there better (more convenient) grounding points?
Question 4: Would any software modification be necessary or is this a 100% pure HW mod?
Question 5: Where can I purchase the worlds tiniest soldering iron? :)
roolku:
Hi Davide-NYC,
the following is to the best of my knowledge, but might well be wrong, so please don't blame me...
--- Quote from: Davide-NYC on April 05, 2007, 09:43:02 PM ---Question 1: Is this drawing correct? (I know I could route the wires better)
--- End quote ---
Looks okay to me.
--- Quote from: Davide-NYC on April 05, 2007, 09:43:02 PM ---Question 2: What would the R and C values be?
--- End quote ---
R you don't need (i.e. connect to ground directly).
C is to suppress spikes and should probably be as close to the IC as possible. Personally I would put it where you drew it though (or even omit it). I guess a value of 47nF would be fine.
--- Quote from: Davide-NYC on April 05, 2007, 09:43:02 PM ---Question 3: Are there better (more convenient) grounding points?
--- End quote ---
I couldn't really find any - possibly the battery connector as it is on the same board and close by.
--- Quote from: Davide-NYC on April 05, 2007, 09:43:02 PM ---Question 4: Would any software modification be necessary or is this a 100% pure HW mod?
--- End quote ---
With just the hardware mod, the player would charge, but be connected in USB mode.
If you want to charge while playing music, you need a software mod as well. It should be straight forward (e.g. enable the defines HAVE_USB_POWER, USBPOWER_BTN_IGNORE and USBPOWER_BUTTON in the right places). I have a patch for that for you if you want.
--- Quote from: Davide-NYC on April 05, 2007, 09:43:02 PM ---Question 5: Where can I purchase the worlds tiniest soldering iron? :)
--- End quote ---
My approach will probably be:
1) get thin stranded wire
2) remove about 3mm insulation
3) cut all but one strand back to 2mm
4) cover expose strands in solder
5) place in such a way that the 1execess strand is above the pin
6) fixate wire with glue to hold it in place and provide strain relieve
7) carefully dip a soldering iron on the single strand above the pin
8) hope it only connects to the one pin it is supposed to connect to
but maybe you have a better idea?
Other comments:
This is the minimal mod. Variations would be:
- connect pin 7 to UCC (3.3V) instead of GND to enable charging with 500mA. Strictly speaking USB needs to negotioate with the host if it can supply 500mA, but most USB ports will provide it by default and I believe other targets do it
- connect pin 7 to a GPO pin of the CPU to switch between charging modes by software. This would obviously require a patch to be able to switch between the modes.
bluebrother:
--- Quote from: roolku on April 06, 2007, 05:11:09 PM ---1) get thin stranded wire
--- End quote ---
I would suggest wrap wire like this (correct me if there is a more appropriate english term for this): http://export.farnell.com/jsp/Cable/Single+Wire/ROADRUNNER/RRP-P-105/displayProduct.jsp?sku=146184
roolku:
--- Quote from: bluebrother on April 06, 2007, 05:50:44 PM ---
--- Quote from: roolku on April 06, 2007, 05:11:09 PM ---1) get thin stranded wire
--- End quote ---
I would suggest wrap wire like this (correct me if there is a more appropriate english term for this):
--- End quote ---
If I understand the listing correctly this is a single strand coated in Polyurethane?
The problem I have is the diameter - on one hand you want it thin (so it is easier to connect) but on the other hand you want it thick for the 100-500mA. (the example is only rated for 82mA - which is probably enough for 100mA, but 500?). Therefore my idea with the stranded wire where only the tip is thin (but covered in solder so hopefully sufficient).
I still can't understand why the pins in a charging IC are that small (the mains charger can deliver up to 2A!).
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