Calculating power, The clock control – Altera Stratix IV GX FPGA User Manual
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Chapter 6: Board Test System
The Clock Control
Stratix IV GX FPGA Development Kit User Guide
March 2014 Altera Corporation
Calculating Power
The Power Monitor calculates power by measuring two different voltages with the
LT2418 A/D and applying the equation P = V × I to determine the power
consumption. The LT2418 measures the voltage after the appropriate sense resistor
(Vsense) and the voltage drop across that sense resistor (Vdif). The current (I) is
calculated by dividing the measured voltage drop across the resistor by the value of
the sense resistor (I = Vdif/R). Through substitution, the equation for calculating
power becomes P = V × I = Vsense × (Vdif/R) = (Vsense) × (Vdif) × (1/.003).
You can verify the power numbers shown in the Power Monitor with a digital
multimeter that is capable of measuring microvolts to ensure you have enough
significant digits for an accurate calculation. Measure the voltage on one side of the
resistor (the side opposite the power source) and then measure the voltage on the
other side. The first measurement is Vsense and the difference between the two
measurements is Vdif. Plug the values into the equation to determine the power
consumption.
The Clock Control
The Clock Control application sets the Si570 programmable oscillator to any
frequency between 10 MHz and 810 MHz with eight digits of precision to the right of
the decimal point. The oscillator drives a 2-to-4 buffer that drives a copy of the clock
to all four edges of the FPGA.
The Clock Control application runs as a stand-alone application. ClockControl.exe
resides in the <install
dir>\kits\stratixIVGX_4sgx230_fpga\examples\board_test_system directory. On
Windows, click Start > All Programs > Altera > Stratix IV GX FPGA Development
Kit
<version> > Clock Control to start the application.
f
For more information about the Si570 and the Stratix IV GX FPGA development
board’s clocking circuitry and clock input pins, refer to the
.