iRiver iHP-120/140 USB charge with BQ24022

[ItsJustMe]

I would like to charge my player via USB (or at least stop it from discharging while plugged). The Li-Ion charger IC is a Texas Instruments BQ24022 which is capable of USB charge but this function is unused.

A look at http://focus.ti.com/lit/ds/symlink/bq24022.pdf tells me that I need to wire:

USB VBUS <-> BQ24022 pin 2 (USB)
USB VBUS <-> Ground, over capacitor (value?)
BQ24022 pin 7 (ISET2) <-> Ground, over resistor (value for low charge rate?)
Some sort of over voltage protection?

At the moment i use the old mod (USB VBUS <-> DC In +) already described in this forum but that does not look very elegant. For example charges are always interrupted on disk access.

Do you think it's possible to implement that?   Help would be appreciated  

[roolku]

I looked at this some time ago and abandoned the idea. Unfortunately I can't remember why. Maybe it will come back to me. If it works out I think this would be a cool mod.

Roolku

[LinusN]

It should be possible. You need to lift the USB pin on the BQ24022 because it is currently connected to the DC-in, and then connect it to VBUS.

[Davide-NYC]

I posted a link to this thread in the RTC mod thread so that maybe one of the hardware geniuses over there might be of some assistance. This would be a righteous mod!

[roolku]

I looked at this some time ago and abandoned the idea. Unfortunately I can't remember why.

I now remember what put me off. The 0.5 mm pitch! That will take some courage to solder a couple of wires on.

[ItsJustMe]

@LinusN
Are you shure? I thought the USB pin (pin 2) is just unused. Hm, that does not make sense to me.

@Davide-NYC
Thank you. I just ordered a DS3231 because I would like to do both modifications.

@roolku
You are right. That would be a challenge.

[LinusN]

@LinusN
Are you shure? I thought the USB pin (pin 2) is just unused. Hm, that does not make sense to me.

I saw this when I traced the PCB in the beginning of the project, and I was equally confused. I just traced it again, and now they aren't connected...!!! I guess I was tired that day.

So, the good news is that they are *not* connected. Sorry for the confusion.

[syrou]

I find this mod very interesting (as much as the RTC one). I'm not sure, but maybe making a bridge between USB conn pin 1 and pin 2 of BQ chip, and grounding pin 4 of USB conn (if it isn't already) works. Is BQ pin 7 important?

[Davide-NYC]

Guys any news on this?

I have a broken H120 I will be trying to fix in the next couple of weeks (need to find time) and would be willing to "try stuff" on it if I get the unit working.

In other words: If I can get it to work I'm willing to risk breaking it again.

Lemme know.

[ItsJustMe]

I'm not sure, but maybe making a bridge between USB conn pin 1 and pin 2 of BQ chip, and grounding pin 4 of USB conn (if it isn't already) works.

Pin1 is DC in, pin 2 is USB in. A bridge does not make sense to me. USB in is limited to 500mAh and could be destroyed. I don't know what would happen if both USB and DC are connected. USB pin 4 (Ground) should be grounded anyway.

Is BQ pin 7 important?

As long as pin 7 is in "high-z" state, USB charge function of BQ is disabled. A pull up gives 500mAh charge current, pulled down we have 100mAh. A resistor between 10k and 100k should be fine (i am not shure).

My DS3231 arrived, perhaps i will try both mods soon but i'm afraid of the 0.5mm pitch.  

[Davide-NYC]

My DS3231 arrived, perhaps i will try both mods soon but i'm afraid of the 0.5mm pitch.  

Hey ItsJustMe, if you give me detailed instruction (with pictures or diagrams) and I am able to repair my broken iriver I am more than willing to attempt this mod.

Your instructions will have to be idiot-proof. (I am that idiot)
On the other hand I did successfully install the RTC chip so I'm not that bad.  

Looking forward to hearing from you!  

[GaardenZwerch]

I use a Y cable that a mini USB plug and a charger tip at one end and male USB plug on the other end. This works nicely for chargin on my Desktop. However, one day I had both USB and power plugged into my IHP 120. When I plugged the other end into my laptop, it just switched off.  I haven't really tried to reproduce this since, because I'm not too keen on frying the USB port in my laptop, or even the laptop itself.

So I would rather not have this mod inside my Iriver... with the cable I can either 'just charge' or 'just plug USB' if I'm not sure the USB port can handle the current that is drawn. Additionnally, I wouldn't want to be charging each time I plug in... I like to let my batteries come 'close to empty' before charging them. I still believe this enhances their overall lifetime a bit...

Hope this helps you decide wether you want to try this mod

Have a nice day,

Frank

[Davide-NYC]

If I could charge from the USB cable I'd be willing to even remove the DC in jack, although I don't really understand why this would be necessary. As long as I didn't plugin both USB and DC in at the same time it should be OK right?

Am I missing something? (it wouldn't be the first time)

[roolku]

The point of this mod is to use the built-in USB charging functionality of the BQ24022 which for some reason is not utilised on the h1x0. The chip takes care of how much current is drawn from the USB port and is perfectly save to use.

It is not comparable to the cable 'hack' GaardenZwerch uses.

[Davide-NYC]

That's what I suspected but didn't want to presume anything since I have little expertise in this particular field.

@ anyone that knows their stuff:: Post instructions and I'll attempt this on one of my H1x0s in the name of Rockbox!