Pyra PMIC


WizardStan

Mega GP Mania
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May 24, 2008
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What PMIC did you or Nikolaus choose for the Pyra? I'd like to read up on the differences with the Pandora's TWL4030.
 
Unfortunately I've come up with nothing.  I can't even confirm that the TWL6037 has any sort of battery circuitry at all, there's no discussion about inputs anywhere so it could be just a glorified voltage regulator: one in, many out.  I'd be surprised if it didn't, it seems to be an updated 6030 so I'd expect it to have a complete superset of features, but then again I'm surprised at the complete lack of information for it at all; perhaps there's a reason for that.
It wouldn't be the end of the world if the Pyra used the same as in the Pandora, I was just hoping for something better.
 
Didn't see this thread earier. Yes it is a twl6037 (aka "Palmas") which has ca. 10 DC/DC converters, ca. 10 LDOs, RTC, a poweron/off button decoder and a 16 channel ADC with VBUS and ID pin detector.

Compared to the twl4030 it has no audio (which is done by twl6040) and it has no keypad controller (which is done by a tca8418). And there is no integrated charger. The Pyra will have a bq24297 for that.
 
Perfect.  I thought I was losing my mind when I couldn't find any information on battery charging through the TWL6037.
I'll have a look at the BQ24297, battery charging capabilities is all I really care about right now.
Thanks!
 
Dos this Batterie Loading circuit have a own Charge Firmware??

At Pandora, you have to boot up the whole OS to charge,

So how it is on Pyra??
 
Well, the twl4030 in the Pandora also can charge the battery on its own - but only in trickle charge mode (50-100mA). But the boot loader increases to 500mA or so. With full OS you have more modes.
For the Pyra it is completely self-contained (incl. USB charger detection) and charges empty and almost empty batteries. But can be controlled a little by the OS.
 
 
It also looks like the BQ24927 has a better voltage regulator so that you can hot swap the battery.
 
Yes :) At least if the power supply is good enough to run the Pyra w/o battery support.

BTW: on the GTA04 we also have the twl4030 (tps65950) and there it is possible to hot-swap the battery, provided Linux is running and the USB charger current limit has been increased to the maximum. So it may be more a software issue than hardware on the Pandora.
 
Well that's interesting.
The Pandora had two problems, at least according to MWeston: if the battery is removed then it loses power while it switches to constant voltage mode, resulting in a reboot; and if the battery is replaced there's a power spike where it gets voltage from both the battery and the socket for a very brief moment until it can turn off constant voltage mode.
The first was easy to verify, and I'd never found a way around it, even on AC power with the current cranked up to 2A it still reset.  The second I was too afraid to play with, I've seen what too many volts does to electronics. :p
 
By the way, hns:

For you as an Hardware Enginer, whats your overall Opinion about the Pandora Hardware Design??

I mean, to make the Pyra, i could image you took a lock on the Pandora Board and Shematics to know what to increase for the succesor..

The Pyra is not a whole new device, it have lots in common whit the pandora, and there arent much diverent ways to make such a thing..
 
Well, a big difference is that the GTA04 has a 1200mAh battery. So spikes may be lower and not that harmful.
Regarding reuse: we have reused what we could from the Pandora schematics. But it wasn't very much. On block diagram level they are much more similar. The reason is that we have to glue together all chips in an individual way. And for each function block there are many alternatives. But some components are the same :) E.g. the headset jack, the battery connector, the USB2 port connector, some FETs. The original plan was even to use the same SD card readers but in the meantime they became end of life so we had to replace them as well.
 
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