You need to think through the complete problem. Sure you can move the 100uF 
capacitor to the other side of TPS2051, but you still need a bulk capacitor on 
the IN side because of HDMI and VIO requirements. The peak current is based on 
the capacitor ESR and not the size of the capacitor. The size of the capacitor 
affects the duration of the peak current. So, given that you still need a bulk 
capacitor on the TPS2051 IN side, you have achieved little by moving some of 
capacitance to the TPS2051 OUT side. Also, cost of component is only one part 
of the total cost. Carrying additional inventory, cost of placement, 
engineering changes, testing, managing another version, can sometimes be far 
higher than the cost of the component. Anyway, even doing what you asked for 
will do little to reduce the peak current, so why go through the exercise. 
Doesn’t make sense to me. 

Regards,
John




> On Jul 5, 2016, at 8:18 AM, [email protected] wrote:
> 
> John, thank you for your feedback!
> 
> Looks like the central question what is the "correct power supply", moreover 
> what is the standard to protect from overcurrent by power supply.
> 
> 1). Oldest method is: fuse.
> 2). Old method is: if the load heavy than power supply capability then limit 
> current to maximum (decrease output voltage).
> 3). if the load heavy than power supply capability then decrease output 
> voltage using diffrent characteristic.
> 4). If power supply detect overcurrent, then switch of output voltage for 
> specifyed time and then try it again.
> 
> Next question is: how long overcurrent is overcurrent?
> a). Overcurrent for 1ms? 
> b). Overcurrent for 100ms? 
> c). Overcurrent for 1s?
> 
> Present method used by BBB is match just for power suppy which use method 2b 
> and c.
> That is why I say, moving "CAP" from TPS2051 IN to OUT make board compatible 
> power suppy which use method 1-4 (near all).
> 
> 
> But the main probelm is: manufacturers not specify what is the current 
> protection method for its power supply. Therefore you cannot select "correct 
> power supply" which use method 2.
> 
> Othersides I understand your cost problem. But current board has enough space 
> to place one more 10uF 10V capacitor (see C7, C8, C10, C13). And it is cost 
> less than 0,01USD. I think is this worh for mouch wide power supply 
> compatbility.
> 
> 
> -- 
> For more options, visit http://beagleboard.org/discuss 
> <http://beagleboard.org/discuss>
> --- 
> You received this message because you are subscribed to the Google Groups 
> "BeagleBoard" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to [email protected] 
> <mailto:[email protected]>.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/beagleboard/2cab5de7-371e-4af5-aaae-1d5068f3e855%40googlegroups.com
>  
> <https://groups.google.com/d/msgid/beagleboard/2cab5de7-371e-4af5-aaae-1d5068f3e855%40googlegroups.com?utm_medium=email&utm_source=footer>.
> For more options, visit https://groups.google.com/d/optout 
> <https://groups.google.com/d/optout>.

-- 
For more options, visit http://beagleboard.org/discuss
--- 
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/52136560-41F4-475F-A504-B9CCD842CFB6%40gmail.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to