Example Low Power Use Cases
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SPRAC74A–February 2017–Revised March 2017
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AM335x Low Power Design Guide
4.4 Optimized Systems Under Load
Now that you know what these systems are like at idle, what happens when they are required to perform
computation or communicate with the outside world? The Dhrystone and IPerf cases use the same setup
as the OS Idle, and Networked OS Idle cases, respectively. The only difference here is that in Dhrystone,
a load was put on the MPU and memory, and in IPerf, MPU, I/O, and memory power domains are all
involved.
4.4.1 Dhrystone
Device Tree Name Ethernet SGX
am335x-evm-powersave.dtb No No
Dhrystone version run is the standard compiled version that comes with Processor SDK.
Table 11. Optimized Dhrystone Power Consumption
Power Rail Voltage (V)
MPU OPP50
(300 MHz)
MPU OPP100
(600 MHz)
MPU OPP120
(720 MHz)
MPU OPP
Turbo
(800 MHz)
MPU OPP Nitro
(1000 MHz)
Power (mW) Power (mW) Power (mW) Power (mW) Power (mW)
vdd_core_power 1.1 153.77 158.40 159.86 160.81 164.42
vdd_mpu_power DVFS (0.95 -
1.325)
106.79 282.56 407.28 502.32 680.71
1.8V I/O 1.8 34.74 38.70 40.68 41.73 45.16
3.3V I/O[1] 3.3 20.83 20.78 20.75 20.75 20.72
SoC Power without DDR3 316.13 500.44 628.57 725.61 911.01
vdds_ddr 1.5 134.43 137.10 140.77 150.13 148.35
vddsddrmem 1.5 117.22 131.58 130.30 153.40 159.81
DDR3 Total Power (Includes VTT) 251.65 268.68 271.07 303.53 308.15
Total Power (SoC + DDR3) with
VTT
567.78 769.12 899.64 1029.17 1219.17
Using DDR3L data sourced from the BeagleBone Black, the power consumption of a VTT-less DDR3L
system can be approximated. VDCDC1 includes both the DDR3L memory power as well as the EMIF
interface on the AM335x. SoC power from AM335x GP EVM data summarized in Table 11.
Power Rail Voltage (V)
MPU OPP50
(300 MHz)
MPU OPP100
(600 MHz)
MPU OPP120
(720 MHz)
MPU OPP
Turbo
(800 MHz)
MPU OPP Nitro
(1000 MHz)
Power (mW) Power (mW) Power (mW) Power (mW) Power (mW)
DCDC1
(DDR+I/O)
1.35 56.27 69.80 75.15 79.04 106.56
SoC Power 316.13 500.44 628.57 725.61 911.01
Total Power (SoC + DDR3L)
without VTT
372.40 570.24 703.72 804.65 1017.57
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