Key Components Description and Operation
UG0617 User Guide Revision 4.0
11
4
Key Components Description and Operation
This section describes the key component interfaces of the RTG4 Development Kit. For device
datasheets, see
http://www.microsemi.com/products/fpga-soc/design-resources/dev-kits/rtg4-
development-kit
.
4.1
Powering Up the Board
The RTG4 Development Board is powered using a 12 V external DC jack (12P0V_Ext), as shown in the
following figure.
To power up the board:
1.
Connect the 12 V power supply brick to the
J9
to supply power to the board.
2.
Switch ON the
SW6
power supply switch.
Figure 4 •
Powering Up the Board
4.2
Current Measurement
This section provides information about current sensing in various modes.
4.2.1
1.2 V Current Sensing for Normal Operation
For applications that require current measurement, high-precision operational amplifier circuitry (U5 with
gain 5) is provided on the board to measure the output voltage at the
TP16
test point.
The following steps describe how to measure the core power.
1.
Measure the output voltage (V
out
) at TP16.
2.
I = V
out
/(5*0.05), where 5 is the gain of the operational amplifier U5 and 0.05 is the current sense
resistor value in ohms.
3.
P = VI, where V is voltage at TP14 and I is voltage at TP16*4.
4.
Therefore, core power consumed (P) = V(TP14)*V(TP16)*4.
For example, when the voltage measured across TP16 is 0.5 V, the core power consumed is 2.4 W.
The following figure shows the on-board core power measurement circuity.
Figure 5 •
Core Power Measurement
12P0V_Ext
12P0V_IN
2
5
1
3
4
6
12P0V
SW6
J17
ENABLE_FT4232
0.05? _1%
12 V
1.2 V
Gain
5
5.0 V
TP16
U5
TP14
1.2 V Regulator
PTH08T230WAZ
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