3 – Key Components Description and Operation
14
IGLOO2 FPGA Evaluation Kit User Guide
1.2 V Regulator
LX7165
0.05
Ω_1%
5.0 V
1.2 V
Gain
100
5.0 V
TP14
U31
TP16
TP17
Figure 5.
Core Power Measurement
Figure 5
shows the onboard core power measurement circuitry.
1.2 V Current Sensing for Flash*Freeze
The IGLOO2 device consumes very low power in Flash*Freeze mode. The voltage across the sense resistor (0.05
ohms) needs to be measured directly using a precision digital multi-meter that can read sub milli-volts. Test points
TP16 and TP17 can be used to directly measure voltage across the 1.2 V sense resistor.
To convert the voltage measured across sense resistor to power, use the following equation:
𝑃𝑜𝑤𝑒𝑟 = (
voltage_measured_in_milli_volts
0.05
) ∗ 1.2
1.8 V Current Sensing
For applications which require current measurement high precision Operational Amplifier circuitry (U32 with gain 100)
is placed on the board to measure the output voltage at TP15 test point with reference to the ground.
1.8 V power can be measured by following these steps:
1. Measure the output voltage (VOUT) at TP15.
2. I = (VOUT/5)
3. Power consumed P= (1.8 V)*I
For example, when the voltage measured across TP15 as 0.5 V, then the consumed core power is 0.18 W.
1.8 V Regulator
LX7167
0.05
Ω_1%
5.0 V
1.8 V
Gain
100
5.0 V
TP15
U32
Figure 6.
1.8 V Power Measurement
Figure 6
shows the onboard 1.8 V power measurement circuitry.
Note:
The measured accuracy is ± 10%.
