IÂ´m evaluating if my power solution is the best choice for my design.I choosed this PMIC because itÂ´s simple and cheap.
Actually i have a TPS65218 PMIC for 1.1V, 1.2V, 2.5V and 1.8V and two independent Bucks for 1.5V for DDR plus the termination LDO and another for 3.3 V for FPGA and IO
The TPS65218 PMIC haves 4 DCDC converters:
- DCDC 1, 2, 3 -> 1.8A max They generate 1.1 V - 1.2V for Processor System and 2.5 for Processor and FPGA
- DCDC 4 -> 1 A max It generates 1.8V for Ethernet and HDMI
In some development boards power blocks i see that 1.1V are rated for 3A and in others 6A Â¿Are they crazy?While running the altera Power Play Estimator (This Excel) iÂ´m getting only 0.7 A required for 1.1V at full load
So i cant understand why the dev boards use 1.1V 3A DCDC SOLUTION
Just in case, iÂ´m planing to change my power block replacing the TPS65218 PMIC by a TPS659037 solution (So much powerful and BGA
Here the TPS659037 specsOne 0.7 to 1.65V at 6 A One 0.7 to 1.65 V at 4 One 0.7 to 3.3 V at 3 A
Two 0.7 to 3.3 V at 2 A
Two 0.7 to 3.3 V at 1 A
Seven General-Purpose LDOÂ´s
Will my actual 1.1 V 1.8 A be suitable for A9 Dual Core At 924 MHZ ?
Thank you in advance !!
On the development board supplies schematics they have a total of 14 - 20 Ampsof total currents but the board is supplied with a 2A wall adapter So i will desolder the inductors and measure currents with my Agilent U1273A at full loads, full- stressing the processor and FPGA
hereÂ´s nothing like real measurements !!
HereÂ´s some strange
I think that a development board should be a reference design so overdimension of supplies are a WRONG WAY
to do a reference board !!!
Maybe this is because they have the parts for free... IÂ´m not !
robertferanec, 07-21-2016, 08:32 PM
Usually the high current regulators are used to cover current peaks. Also, sometimes the power is designed the way to get option to fit the most powerful pin to pin compatible chip or possibly next generation pin to pin compatible chips which you may not know about. I am always very careful about powers and if I am not sure, I use power supply with at least the same maximum current as they used in the reference design. If you underpower a rail, the board may be occasionally crashing (or behaving unstable or weird) and you may not be able to find out what is causing the problem. Debugging this kind of issue is extremely time consuming and it can be very frustrating.