I've a few digital potentiometers I want to introduce into guitar pedals(?!) but they're tiny. I've been etching my own converters but keep over-cooking it on the tiny 0.25mm traces.
----- Original Message ----- From: Chris Holden To: brightonhackerspace@googlegroups.com Sent: Tuesday, August 28, 2012 6:51 PM
Subject: [brighton-hacker-space] anyone got any of those soic to dip converters?
I've a few digital potentiometers I want to introduce into guitar pedals(?!) but they're tiny. I've been etching my own converters but keep over-cooking it on the tiny 0.25mm traces.
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> It's not the toner transfer - it's the FeCl etching that's doing for me!
> On 28/08/2012 19:08, BotBuilder wrote:
> Laser etch your PCBS :-)
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On Tue, Aug 28, 2012 at 7:50 PM, Toby Cole <t...@tubs.org.uk> wrote:
> Jason may have some, think he was on hols though.
> T
> On Tue, Aug 28, 2012 at 7:10 PM, Chris <chris.hol...@multiedge-net.co.uk>wrote:
>> It's not the toner transfer - it's the FeCl etching that's doing for me!
>> On 28/08/2012 19:08, BotBuilder wrote:
>> Laser etch your PCBS :-)
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just back off hols so sorry for late response – yes I have some SOIC to DIP converters, but for how many pins do you need – and are you sure you mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs (which are smaller)
Hi Jason,
It's the other Chris. I'm also looking for some of these adapters for a 5 pin charge controller. Not sure about the size. I'm using the ones which came from Chris's golf score project. Will need 2 of them.
On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
> Hey Chris
> just back off hols so sorry for late response – yes I have some SOIC to > DIP converters, but for how many pins do you need – and are you sure you > mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs > (which are smaller)
Hi Chris
do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins sounds like it may be a weird package
Cheers
Jason
From: Christopher Hills Sent: Monday, September 17, 2012 9:25 AM
To: brightonhackerspace@googlegroups.com Subject: Re: [brighton-hacker-space] anyone got any of those soic to dip converters?
Hi Jason,
It's the other Chris. I'm also looking for some of these adapters for a 5 pin charge controller. Not sure about the size. I'm using the ones which came from Chris's golf score project. Will need 2 of them.
Thanks
On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
Hey Chris
just back off hols so sorry for late response – yes I have some SOIC to DIP converters, but for how many pins do you need – and are you sure you mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs (which are smaller)
Cheers
Jason
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Good question, I'm still on the hunt for a data sheet for them, so the package type is unknown at this time. The markings on the chip are 54IJ and Chris said that he bought them from Microchip.
I have looked on their site and found this one. http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982 which could be the one I'm looking for. It shows the package as 5/SOT-23
On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
> Hi Chris
> do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins sounds like > it may be a weird package
> Cheers
> Jason
> *From:*
> *Sent:* Monday, September 17, 2012 9:25 AM
> *To:* brightonh...@googlegroups.com <javascript:> > *Subject:* Re: [brighton-hacker-space] anyone got any of those soic to > dip converters?
> Hi Jason,
> It's the other Chris. I'm also looking for some of these adapters for a 5 > pin charge controller. Not sure about the size. I'm using the ones which > came from Chris's golf score project. Will need 2 of them.
> Thanks
> On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
>> Hey Chris
>> just back off hols so sorry for late response – yes I have some SOIC to >> DIP converters, but for how many pins do you need – and are you sure you >> mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs >> (which are smaller)
>> Cheers
>> Jason
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6 Pin SOT23 Adapter
Adapter for standard 6 pin SOT23 SMD Parts to convert to standard DIP size
Part Code: 6PINSOT23
From: Christopher Hills Sent: Monday, September 17, 2012 12:50 PM
To: brightonhackerspace@googlegroups.com Subject: Re: [brighton-hacker-space] anyone got any of those soic to dip converters?
Hi Jason
Good question, I'm still on the hunt for a data sheet for them, so the package type is unknown at this time. The markings on the chip are 54IJ and Chris said that he bought them from Microchip.
I have looked on their site and found this one. http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982 which could be the one I'm looking for. It shows the package as 5/SOT-23
Thanks
Chris
On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
Hi Chris
do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins sounds like it may be a weird package
Cheers
Jason
From:
Sent: Monday, September 17, 2012 9:25 AM
To: brightonh...@googlegroups.com Subject: Re: [brighton-hacker-space] anyone got any of those soic to dip converters?
Hi Jason,
It's the other Chris. I'm also looking for some of these adapters for a 5 pin charge controller. Not sure about the size. I'm using the ones which came from Chris's golf score project. Will need 2 of them.
Thanks
On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote: Hey Chris
just back off hols so sorry for late response – yes I have some SOIC to DIP converters, but for how many pins do you need – and are you sure you mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs (which are smaller)
Cheers
Jason
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I'm still looking for my original schematics and firmware but they look like the ones.
You can use a pull-up/down resistor to set the charge to 100mA or 500mA (actually about 90mA and 450mA) so you don't violate USB charging protocols. In my devices they were set to charge at 100mA so find the pull-up/down resistor and reverse it (if it's currently pulling to ground, pull it to 5v or vice versa).
They're really easy to use and stop any worry about over/under voltage.
> Good question, I'm still on the hunt for a data sheet for them, so the > package type is unknown at this time. The markings on the chip are > 54IJ and Chris said that he bought them from Microchip.
> I have looked on their site and found this one. > http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982 > which could be the one I'm looking for. It shows the package as 5/SOT-23
> Thanks
> Chris
> On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
> Hi Chris
> do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins
> sounds like it may be a weird package
> Cheers
> Jason
> *From:*
> *Sent:* Monday, September 17, 2012 9:25 AM
> *To:* brightonh...@googlegroups.com <javascript:>
> *Subject:* Re: [brighton-hacker-space] anyone got any of those
> soic to dip converters?
> Hi Jason,
> It's the other Chris. I'm also looking for some of these adapters
> for a 5 pin charge controller. Not sure about the size. I'm using
> the ones which came from Chris's golf score project. Will need 2
> of them.
> Thanks
> On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
> Hey Chris
> just back off hols so sorry for late response � yes I have
> some SOIC to DIP converters, but for how many pins do you need
> � and are you sure you mean SOIC? the pitch on those is bigger
> than 0.25mm. Do you mean SOPs (which are smaller)
> Cheers
> Jason
> -- > You received this message because you are subscribed to the Google > Groups "BuildBrighton - the Brighton Hacker Space" group.
> To post to this group, send email to brightonhackerspace@googlegroups.com.
> To unsubscribe from this group, send email to > brightonhackerspace+unsubscribe@googlegroups.com.
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Looking at the data sheets and your device. You have used the MCP73812 to get
resistor-programmable charge current (up to 500ma) as I can see a 2Kohm res attached to one of the pins on the charge controller chip. Where as the MCP73811 uses 2 1 micro f caps to set a charge rate of 85mA or 450mA though logic.
I could go with the resistor method but Is 500mA too high for 1000mA batteries, when used to charge them? Also I could check the current output with a voltmeter just to be sure.
On Monday, 17 September 2012 13:03:42 UTC+1, Chris Holden wrote:
> I'm still looking for my original schematics and firmware but they look > like the ones.
> You can use a pull-up/down resistor to set the charge to 100mA or 500mA > (actually about 90mA and 450mA) so you don't violate USB charging > protocols. In my devices they were set to charge at 100mA so find the > pull-up/down resistor and reverse it (if it's currently pulling to ground, > pull it to 5v or vice versa).
> They're really easy to use and stop any worry about over/under voltage.
> On 17/09/2012 12:50, Christopher Hills wrote:
> Hi Jason
> Good question, I'm still on the hunt for a data sheet for them, so the > package type is unknown at this time. The markings on the chip are 54IJ and > Chris said that he bought them from Microchip.
> I have looked on their site and found this one. > http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982� > which could be the one I'm looking for. It shows the package as 5/SOT-23
> Thanks
> Chris
> On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
>> Hi Chris
>> do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins sounds >> like it may be a weird package
>> Cheers
>> Jason
>> �
>> *From:*� >> *Sent:* Monday, September 17, 2012 9:25 AM
>> *To:* brightonh...@googlegroups.com >> *Subject:* Re: [brighton-hacker-space] anyone got any of those soic to >> dip converters?
>> �
>> Hi Jason,
>> It's the other Chris. I'm also looking for some of these adapters for a 5 >> pin charge controller. Not sure about the size. I'm using the ones which >> came from Chris's golf score project. Will need 2 of them.
>> Thanks�
>> On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
>>> Hey Chris
>>> �
>>> just back off hols so sorry for late response � yes I have some SOIC >>> to DIP converters, but for how many pins do you need � and are you sure >>> you mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs >>> (which are smaller) >>> �
>>> Cheers
>>> Jason
>>> �
>> -- >> You received this message because you are subscribed to the Google Groups >> "BuildBrighton - the Brighton Hacker Space" group.
>> To post to this group, send email to brightonh...@googlegroups.com.
>> To unsubscribe from this group, send email to >> brightonhackerspace+unsubscribe@googlegroups.com.
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>> �
>> �
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> .
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> �
> �
The 85/450 is max charge rate. If you look at the charge graph in the datasheet, the chip itself controls the total charge current.
It starts off slow, then allows an inrush of current between about 20%-80%, then throttles the charge for the last few percent of the battery. I forget the exact values, but the charge graph looks like a letter -S on a slant; all controlled by the chip, whichever max. current option is used.
I went for the 85mA option because without negotiating properly, a USB host will only provide up to 100mA.
I wanted to make sure my device would pass all CE testing and conform to USB1.0 so I didn't go above 100mA.
Whether you use the 85mA or the 450mA setting shouldn't matter - the chip takes care of all the charging requirements for you. Except, of course, that it takes longer to charge a lipo at 85mA than it does at 450mA.
If you're going to use a wall supply or other power source, I'd recommend using the 450mA option. I only went for the lower one because it's usb chargeable, nothing to do with the size or current rating of the battery.
As an aside, I'm pretty sure that the included lipos are 1350mA/h - some of my early prototypes used 850mA/h but I think the final production gadgets had 1350. You could use those either in series or parallel to get 7.4v or 3.7v (but don't forget to separate them for charging, I've never tried to make a multi-cell charger and apparently it can get quite complicated without dedicated hardware).
> Looking at the data sheets and your device. You have used the MCP73812 > to get
> resistor-programmable charge current (up to 500ma) as I can see a > 2Kohm res attached to one of the pins on the charge controller chip. > Where as the MCP73811 uses 2 1 micro f caps to set a charge rate of > 85mA or 450mA though logic.
> I could go with the resistor method but Is 500mA too high for 1000mA > batteries, when used to charge them? Also I could check the current > output with a voltmeter just to be sure.
> Thanks
> Chris
> On Monday, 17 September 2012 13:03:42 UTC+1, Chris Holden wrote:
> I'm still looking for my original schematics and firmware but they
> look like the ones.
> You can use a pull-up/down resistor to set the charge to 100mA or
> 500mA (actually about 90mA and 450mA) so you don't violate USB
> charging protocols. In my devices they were set to charge at 100mA
> so find the pull-up/down resistor and reverse it (if it's
> currently pulling to ground, pull it to 5v or vice versa).
> They're really easy to use and stop any worry about over/under
> voltage.
> On 17/09/2012 12:50, Christopher Hills wrote:
>> Hi Jason
>> On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
>> Hi Chris
>> do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5
>> pins sounds like it may be a weird package
>> Cheers
>> Jason
>> �
>> *From:*�
>> *Sent:* Monday, September 17, 2012 9:25 AM
>> *To:* brightonh...@googlegroups.com
>> *Subject:* Re: [brighton-hacker-space] anyone got any of
>> those soic to dip converters?
>> �
>> Hi Jason,
>> It's the other Chris. I'm also looking for some of these
>> adapters for a 5 pin charge controller. Not sure about the
>> size. I'm using the ones which came from Chris's golf score
>> project. Will need 2 of them.
>> Thanks�
>> On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
>> Hey Chris
>> �
>> just back off hols so sorry for late response � yes I
>> have some SOIC to DIP converters, but for how many pins
>> do you need � and are you sure you mean SOIC? the pitch
>> on those is bigger than 0.25mm. Do you mean SOPs (which
>> are smaller)
>> �
>> Cheers
>> Jason
>> �
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> To unsubscribe from this group, send email to > brightonhackerspace+unsubscribe@googlegroups.com.
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Thanks Chris,
I will go with a wall power supply also use a 2K ohm resistor so able to get the 450mA charge rating. The lipos in the device are 850mAh but I don't require them as I'm using 1000mAh CR123A lipos. Don't worry I wont charge in series. The reason for needing 2 of them.
You device's circuit does match the diagram and you used the MCP73812 chip for the 450mA rate but I think becasue you didn't negotiate with the USB host you only got the 85mA rate and if you placed a wall power supply on that circuit you would get the higher rate. I'm I understanding how this works correctly?
So to together with the DIP adapters I should be able to use the charge controllers so able to charge my lipos in situ. :-)
On Monday, 17 September 2012 15:08:24 UTC+1, Chris Holden wrote:
> The 85/450 is max charge rate. If you look at the charge graph in the > datasheet, the chip itself controls the total charge current.
> It starts off slow, then allows an inrush of current between about > 20%-80%, then throttles the charge for the last few percent of the battery. > I forget the exact values, but the charge graph looks like a letter -S on a > slant; all controlled by the chip, whichever max. current option is used.
> I went for the 85mA option because without negotiating properly, a USB > host will only provide up to 100mA.
> I wanted to make sure my device would pass all CE testing and conform to > USB1.0 so I didn't go above 100mA.
> Whether you use the 85mA or the 450mA setting shouldn't matter - the chip > takes care of all the charging requirements for you. Except, of course, > that it takes longer to charge a lipo at 85mA than it does at 450mA.
> If you're going to use a wall supply or other power source, I'd recommend > using the 450mA option. I only went for the lower one because it's usb > chargeable, nothing to do with the size or current rating of the battery.
> As an aside, I'm pretty sure that the included lipos are 1350mA/h - some > of my early prototypes used 850mA/h but I think the final production > gadgets had 1350. You could use those either in series or parallel to get > 7.4v or 3.7v (but don't forget to separate them for charging, I've never > tried to make a multi-cell charger and apparently it can get quite > complicated without dedicated hardware).
> On 17/09/2012 13:46, Christopher Hills wrote:
> Hi Chris,
> Looking at the data sheets and your device. You have used the MCP73812 to > get
> resistor-programmable charge current (up to 500ma) as I can see a 2Kohm > res attached to one of the pins on the charge controller chip. Where as the > MCP73811 uses 2 1 micro f caps to set a charge rate of 85mA or 450mA though > logic.
> I could go with the resistor method but Is 500mA too high for 1000mA > batteries, when used to charge them? Also I could check the current output > with a voltmeter just to be sure.
> Thanks
> Chris
> On Monday, 17 September 2012 13:03:42 UTC+1, Chris Holden wrote:
>> I'm still looking for my original schematics and firmware but they look >> like the ones.
>> You can use a pull-up/down resistor to set the charge to 100mA or 500mA >> (actually about 90mA and 450mA) so you don't violate USB charging >> protocols. In my devices they were set to charge at 100mA so find the >> pull-up/down resistor and reverse it (if it's currently pulling to ground, >> pull it to 5v or vice versa).
>> They're really easy to use and stop any worry about over/under voltage.
>> On 17/09/2012 12:50, Christopher Hills wrote:
>> Hi Jason
>> Good question, I'm still on the hunt for a data sheet for them, so the >> package type is unknown at this time. The markings on the chip are 54IJ and >> Chris said that he bought them from Microchip.
>> I have looked on their site and found this one. >> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982� >> which could be the one I'm looking for. It shows the package as 5/SOT-23
>> Thanks
>> Chris
>> On Monday, 17 September 2012 10:05:55 UTC+1, hotchk155 wrote:
>>> Hi Chris
>>> do you have the designator (SOIC, SOP, MSSOP, SOT etc)? 5 pins sounds >>> like it may be a weird package
>>> Cheers
>>> Jason
>>> �
>>> *From:*� >>> *Sent:* Monday, September 17, 2012 9:25 AM
>>> *To:* brightonh...@googlegroups.com >>> *Subject:* Re: [brighton-hacker-space] anyone got any of those soic to >>> dip converters?
>>> �
>>> Hi Jason,
>>> It's the other Chris. I'm also looking for some of these adapters for a >>> 5 pin charge controller. Not sure about the size. I'm using the ones which >>> came from Chris's golf score project. Will need 2 of them.
>>> Thanks�
>>> On Monday, 3 September 2012 10:17:55 UTC+1, hotchk155 wrote:
>>>> Hey Chris
>>>> �
>>>> just back off hols so sorry for late response � yes I have some SOIC >>>> to DIP converters, but for how many pins do you need � and are you sure >>>> you mean SOIC? the pitch on those is bigger than 0.25mm. Do you mean SOPs >>>> (which are smaller) >>>> �
>>>> Cheers
>>>> Jason
>>>> �
>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "BuildBrighton - the Brighton Hacker Space" group.
>>> To post to this group, send email to brightonh...@googlegroups.com.
>>> To unsubscribe from this group, send email to >>> brightonhackerspace+unsubscribe@googlegroups.com.
>>> To view this discussion on the web visit >>> https://groups.google.com/d/msg/brightonhackerspace/-/ogWhvWPbJh4J.
>>> For more options, visit https://groups.google.com/groups/opt_out.
>>> �
>>> �
>> -- >> You received this message because you are subscribed to the Google Groups >> "BuildBrighton - the Brighton Hacker Space" group.
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>> �
>> �
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I know it's difficult without the original schematics I built and the parts list (I need to dig out my old back up CDs one of these days) - but trust me, I specifically set up the charge controller to charge at the lower rate. I did try them set up at 450 but my PC kept ejecting the USB device when it started charging. If the circuitry on the device I gave you doesn't match what you're seeing on the datasheet, then it's possible the final product uses an alternative (cheaper, Chinese sourced) charge controller chip. I did negotiate for a number of weeks with the factory in Hong Kong and there were a few last-minute revisions to the circuit (Steve would know all about this sort of thing happening) but I'm pretty sure the final product works according to my original prototype - i.e. the charge controller is set up using hardware to be limited to <100mA.
I wouldn't use them in situ since you'll be powering the PIC (and possibly even the LCD display) and the charge-pump circuitry on the QVGA driver board as well as charging the batteries. So you'll only be charging at about 85mA if you don't change the circuitry - and if you do you'll need a wall-wart of more than 1A to get the best/fastest charging rate (since some of the supply will go to these other bits that you're not using).
In short, take the charge-chips off the board and use them independently. Then if you have any problems, you've already eliminated a hundred-and-one possible sources of error before you start debugging.
The internal lipos could be a suitable alternative to your CR123A packs if they have a smaller footprint. I you don't want them, bring them along on Thursday and I'll find a use for them in something else.
To get this subject back on track, I made some SOIC-to-DIP boards myself; four out of eight worked so I'm ok for them now!
> Thanks Chris,
> I will go with a wall power supply also use a 2K ohm resistor so able > to get the 450mA charge rating. The lipos in the device are 850mAh but > I don't require them as I'm using 1000mAh CR123A lipos. Don't worry I > wont charge in series. The reason for needing 2 of them.
> You device's circuit does match the diagram and you used the MCP73812 > chip for the 450mA rate but I think becasue you didn't negotiate with > the USB host you only got the 85mA rate and if you placed a wall power > supply on that circuit you would get the higher rate. I'm I > understanding how this works correctly?
> So to together with the DIP adapters I should be able to use the > charge controllers so able to charge my lipos in situ. :-)
The circuit on the device does match the diagram within the Microchip 732812 data sheet.
I just wanted to get in touch with Jason so I can de-solder the chips and mount them on standard PCB. I'm believe Jason was going to bring some 6 pin adapters to the space on Thursday, which I can use and then my plan is to wire up the circuit to charge each battery as a single unit. The reason for needing 2 chips/devices. The parts left over (screen,batteries etc) can be re-used by anyone. I'm not holding on to them. you gave me the devices out of good will and the code of guesstioneering. I will copy the circuit by using a 2Kohm Res on pin 3 to earth, which is also on the same pin as the plus lead of the battery.
Also before I start charging my batteries, I will use a meter to check the amp output of the chip and see what I get but at the end of the day I'm able to charge the batteries which power the Arduino in situ rather than remove it every time I need to charge the batteries.
On Monday, 17 September 2012 20:32:19 UTC+1, Chris Holden wrote:
> I know it's difficult without the original schematics I built and the > parts list (I need to dig out my old back up CDs one of these days) - > but trust me, I specifically set up the charge controller to charge at > the lower rate. I did try them set up at 450 but my PC kept ejecting the > USB device when it started charging. If the circuitry on the device I > gave you doesn't match what you're seeing on the datasheet, then it's > possible the final product uses an alternative (cheaper, Chinese > sourced) charge controller chip. I did negotiate for a number of weeks > with the factory in Hong Kong and there were a few last-minute revisions > to the circuit (Steve would know all about this sort of thing happening) > but I'm pretty sure the final product works according to my original > prototype - i.e. the charge controller is set up using hardware to be > limited to <100mA.
> I wouldn't use them in situ since you'll be powering the PIC (and > possibly even the LCD display) and the charge-pump circuitry on the QVGA > driver board as well as charging the batteries. So you'll only be > charging at about 85mA if you don't change the circuitry - and if you do > you'll need a wall-wart of more than 1A to get the best/fastest charging > rate (since some of the supply will go to these other bits that you're > not using).
> In short, take the charge-chips off the board and use them > independently. Then if you have any problems, you've already eliminated > a hundred-and-one possible sources of error before you start debugging.
> The internal lipos could be a suitable alternative to your CR123A packs > if they have a smaller footprint. I you don't want them, bring them > along on Thursday and I'll find a use for them in something else.
> To get this subject back on track, I made some SOIC-to-DIP boards > myself; four out of eight worked so I'm ok for them now!
> On 17/09/2012 19:05, Christopher Hills wrote: > > Thanks Chris, > > I will go with a wall power supply also use a 2K ohm resistor so able > > to get the 450mA charge rating. The lipos in the device are 850mAh but > > I don't require them as I'm using 1000mAh CR123A lipos. Don't worry I > > wont charge in series. The reason for needing 2 of them.
> > You device's circuit does match the diagram and you used the MCP73812 > > chip for the 450mA rate but I think becasue you didn't negotiate with > > the USB host you only got the 85mA rate and if you placed a wall power > > supply on that circuit you would get the higher rate. I'm I > > understanding how this works correctly? > > So to together with the DIP adapters I should be able to use the > > charge controllers so able to charge my lipos in situ. :-)
Please re-read the datasheets carefully.
We did discuss - at length - the USB charging requirements both in general and for this specific device.
Anything more than 100mA and the device won't stay connected to a Windows PC; this is the starting point for identifying the charging chip. I did also say that I was using a logic level to set the charge rate - I couldn't remember whether I'd tied the charge pin to power or ground - not analogue.
From the datasheet - For the MCP73811, the constant current value is
selected as 85 mA (low power USB port) or 450 mA
(high power USB port) with a digital input signal on the
PROG input
For the MCP73812, the constant current
value is set with one external resistor
In the datasheet a typical example shown is for a Li-Ion battery (not Li-po). With a 2K resistor to ground on the x12 chip, the charge rate is set to 500mA for LI-ION batteries. This is not the correct battery type, nor the correct charging rate (the device will not connect as a usb device if you try to take more than 100mA from the usb port without negotiating properly; this is part of the USB specification. I did say that I'd never done this and have only ever taken 100mA from the usb port.)
This should have led you to rule out the x12 chip
From the datasheet:
Current Regulation (Fast Charge Constant-Current Mode)
85 — mA MCP73811 - PROG = Low
450 — mA MCP73811 - PROG = High
50 — mA MCP73812 - PROG = 20 kΩ
100 — mA MCP73812 - PROG = 10 kΩ
500 — mA MCP73812 - PROG = 2 kΩ
Since we've ruled out the x812 chip, and we know we can't charge at 500mA, any connection from the charge pin on the chip to ground (whether through a resistor or not) shows that when the PROG pin is pulled low, it charges at 85mA. This is what I explained I had been doing all along!
As the batteries you're using have been shorted and the charge chip connected incorrectly, I would strongly recommend binning the whole lot and buying a ready-made-and-tested solution; there are plenty of videos around the 'net to show that messing about with li-po batteries (without understanding exactly what you're doing) is pretty risky stuff.
On Tuesday, 18 September 2012 18:31:21 UTC+1, Christopher Hills wrote:
> Hi Chris,
> The circuit on the device does match the diagram within the Microchip > 732812 data sheet.
> I just wanted to get in touch with Jason so I can de-solder the chips and > mount them on standard PCB. I'm believe Jason was going to bring some 6 pin > adapters to the space on Thursday, which I can use and then my plan is to > wire up the circuit to charge each battery as a single unit. The reason for > needing 2 chips/devices. The parts left over (screen,batteries etc) can be > re-used by anyone. I'm not holding on to them. you gave me the devices out > of good will and the code of guesstioneering. I will copy the circuit by > using a 2Kohm Res on pin 3 to earth, which is also on the same pin as the > plus lead of the battery.
> Also before I start charging my batteries, I will use a meter to check the > amp output of the chip and see what I get but at the end of the day I'm > able to charge the batteries which power the Arduino in situ rather than > remove it every time I need to charge the batteries.
> Regards
> Chris
> On Monday, 17 September 2012 20:32:19 UTC+1, Chris Holden wrote:
>> I know it's difficult without the original schematics I built and the >> parts list (I need to dig out my old back up CDs one of these days) - >> but trust me, I specifically set up the charge controller to charge at >> the lower rate. I did try them set up at 450 but my PC kept ejecting the >> USB device when it started charging. If the circuitry on the device I >> gave you doesn't match what you're seeing on the datasheet, then it's >> possible the final product uses an alternative (cheaper, Chinese >> sourced) charge controller chip. I did negotiate for a number of weeks >> with the factory in Hong Kong and there were a few last-minute revisions >> to the circuit (Steve would know all about this sort of thing happening) >> but I'm pretty sure the final product works according to my original >> prototype - i.e. the charge controller is set up using hardware to be >> limited to <100mA.
>> I wouldn't use them in situ since you'll be powering the PIC (and >> possibly even the LCD display) and the charge-pump circuitry on the QVGA >> driver board as well as charging the batteries. So you'll only be >> charging at about 85mA if you don't change the circuitry - and if you do >> you'll need a wall-wart of more than 1A to get the best/fastest charging >> rate (since some of the supply will go to these other bits that you're >> not using).
>> In short, take the charge-chips off the board and use them >> independently. Then if you have any problems, you've already eliminated >> a hundred-and-one possible sources of error before you start debugging.
>> The internal lipos could be a suitable alternative to your CR123A packs >> if they have a smaller footprint. I you don't want them, bring them >> along on Thursday and I'll find a use for them in something else.
>> To get this subject back on track, I made some SOIC-to-DIP boards >> myself; four out of eight worked so I'm ok for them now!
>> On 17/09/2012 19:05, Christopher Hills wrote: >> > Thanks Chris, >> > I will go with a wall power supply also use a 2K ohm resistor so able >> > to get the 450mA charge rating. The lipos in the device are 850mAh but >> > I don't require them as I'm using 1000mAh CR123A lipos. Don't worry I >> > wont charge in series. The reason for needing 2 of them.
>> > You device's circuit does match the diagram and you used the MCP73812 >> > chip for the 450mA rate but I think becasue you didn't negotiate with >> > the USB host you only got the 85mA rate and if you placed a wall power >> > supply on that circuit you would get the higher rate. I'm I >> > understanding how this works correctly? >> > So to together with the DIP adapters I should be able to use the >> > charge controllers so able to charge my lipos in situ. :-)
