Same patent, much better site. Shows filing date of July 2010. Pretty new. Is 1 year enough time for something like this to be production-ready?
Secondary lithium ion cell or battery, and protecting circuit, electronic... - US 7749641 B2 - IP.com
edit:
huh... that filing references a previous filing from 2004, which appears to be the same thing...
It's DEEP reading, and I'm trying to get my head around it but it is complicated. It sounds as if it is using PWM (Pulse Width Modulation) Charging IN ADDITION to Linear charging AND Burst Charging, and supplies the varied voltage to the battery AND the Bus so the phone (apparently) can use a higher voltage than the battery can supply. With PWM you can send voltage pulses several hundred times a second, each one carrying a small amount of amperage. You can also keep the amount of pulses per second the same but increase the length of the pulses, allowing them to deliver more current or ramp up voltage for a longer period of time in the same amount of pulses, but each lasting longer. Get's confusing! If everything available on this chip is being used, it is very advanced and brand spanking new. RC Motor speed controls work on a very similar principle and are considered computers themselves... and cost $125 to $250.
If you can hit a battery with 100's of short higher pulses of voltage carrying low amperage, I can see how that would work... not enough amperage going through to damage it. I'm stuck on the linear part though... the continuous charge it's also capable of. A constant stream of higher current... with that if it were to be over 4.2 volts the same rules should still apply, but it sounds as if this chip is doing the PWM, the linear, bursts, and in addition has an "overflow" available if the voltage is going too high.
It would be great if this IS new cutting edge technology and (I hope) I'm reading it right, as it would indicate you can charge the battery at a higher voltage but not in the "traditional" way. It doesn't sound like heat should be a major side effect though and I don't believe it is as designed. So if the voltage IS supposed to be high (?) but not generate heat, that is a very good thing as it indicates all the phones are supposed to be getting that pulsed width modulation at the higher voltage... it's just the phones that are having the heating issues with it that have the problem. A certain number of unit failures out of "X" amount sold, due to the chip being so new of course there will be some units that don't work as designed... that's the case with most every kind of phone release with every carrier.
It's odd though... I've been trying to find other documents on this kind of charging... Linear/PWM/burst mix and they seem to say it's important to still not let the battery voltage exceed the 4200mv, but Voltage Bus can be 4530 mv.... is it possible he phone is reading the "voltage bus" and not the actual voltage of the battery?
A document I was looking at... it's not in the phone, but also explains the charging in a similar way that is still complicated, but a little easier to grasp on.
The fact that they haven't been able to duplicate the problem when it appears others here have been able to OR it just occurs without their trying is a concern, BUT since it isn't a problem with all the phones and only some, they will have to get a hold of a phone with the problem to test it. Sprint has one of mine, so I would like to think either they or HTC will do some testing to verify it.... then fix it and not just say "Most Android phones run warm" and leave it at that. I know that, and most anybody who has owned one does too. Nature of the beast.
