[gta02-core] More audio considerations

[Álvaro Lopes]

Werner Almesberger wrote:
> I wrote:
>> 2) LDO delivers the extra current until thermal shutdown stops it.
> 
> I did some measurements on a GTA02v4 with an overload condition on LDO4
> (BT_3V2):
> 
> State           LDO4 (nominal)	Rload   Ibat (Vbat = 4.2 V)     BT_3V2
> --------------- --------------- -----   -------------------     ------
> Idle            LDO4 = 0 V      open    104 mA                  3.29 V
> Overload        LDO4 = 3.3 V    10 R    422 mA                  3.05 V
> Short           LDO4 = 3.3 V     0 R    510 mA                  0.01 V

That makes 2.1W. Glad you stopped :)

So I guess we can handle those peaks for a short time, can't we ?

> 
> So the LDO does eventually limit the current, but around 500 mA, which
> is considerably above the nominal limit of 150 mA. 
> 
> Note that the system didn't reset or crash during this experiment. The
> PMU got fairly warm after a while, so I stopped.

I wonder if, as last resort, we can put a NTC there. I am not sure such thing exists as SMT NTC however.

Álvaro