AP0164 Power Monitoring on the Desktop NanoBoard NB2DSK01

8132019 AP0164 Power Monitoring on the Desktop NanoBoard NB2DSK01

httpslidepdfcomreaderfullap0164-power-monitoring-on-the-desktop-nanoboard-nb2dsk01 18

Power Monitoring on theDesktop NanoBoard NB2DSK01

Version (v10) May 20 2008 1

As the number of daughter boards and peripheral boards continues to grow ndash both those

designed by Altium and those made externally ndash the number of different hardware

configurations possible for a Desktop NanoBoard NB2DSK01 becomes considerable Add

to this the ability to connect expansion devices to the NB2DSK01s User Headers again

changing the configuration of the system While developing embedded intelligence the

ability to monitor and compare the power consumption of different Desktop NanoBoard

configurations would be an invaluable tool

The Innovation Station offers exactly this ability Current monitoring hardware is provided

on the Desktop NanoBoard while access to the resulting power current and voltage

information is facilitated through instrumentation within Altium Designer

Desktop NanoBoard

NB2DSK01

Peripheral Board A

Peripheral Board B

Peripheral Board C

Altium Designer

Board connected to

User Header A

Board connected to

User Header B

Daughter Board

NanoTalk

Controller

Current-Sensing

Circuitry

Power Supplies

12V 18V 25V 33V 5V

Figure 1 Simplified diagram showing the power monitoring concept for Altiums Innovation Station

SummaryThis application note

provides information on

the Power Monitoring

functionality provided for

the Desktop NanoBoard

NB2DSK01 It covers

how this functionality is

supported in the

hardware and how to

access the monitoring

features from within

Altium Designer



AP0164 Power Monitoring on the Desktop NanoBoard NB2DSK01


Functionality at the Hardware-Level

Before looking at how the power monitoring functionality is accessed within the software it is worth taking a look at the

underlying hardware by which such power monitoring of the system is made possible

On the NB2DSK01 motherboard current monitoring is in place for each of the following power lines

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD A connector

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD B connector

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD C connector

bull 33V and 5V lines routed to the corresponding connectors for the daughter board

bull 33V or 5V line selected for use with User Header A connector

bull 33V or 5V line selected for use with User Header B connector

A total of 19 monitored power lines

In terms of hardware this monitoring is

achieved through use of a MAX4372T high-

side current sense amplifier (from Maxim)Each power line is routed to its destination

connector through a 47mΩ resistor which

serves as the external sense resistance for

the associated MAX4372T device Powered

by the NB2DSK01s 9V supply this device

provides a voltage output that is proportional

to the voltage across this sense resistance

and has a fixed gain of 20

For current passing through the 47mΩ

resistor the voltage across the devices input

is 47uVmA The output of the device is

therefore 940uVmA (applying the x20 gain)

Two low-power 12-channel 12-bit ADC devices (MAX1229 from Maxim) collect together the analog voltage outputs from all

current sense amplifiers for transmission back to the NB2DSK01s Xilinx Spartan-3 Controller FPGA (the NanoTalk Controller)

over an SPI bus

Figure 3 Schematic fragment showing the two ADC devices which pass the subsequently converted data to the NanoTalk Controller over theSPI bus and subsequent processing by the firmware

The output of each ADC which has an internal reference voltage of 25V is

ADC output = (25V4096) 940uV = 064931mAbit (=265957A full scale)

For more information on the MAX4372T and MAX1229 devices refer to the datasheets (MAX4372-MAX4372Tpdf and

MAX1227-MAX1231pdf) available at wwwmaxim-iccom

Figure 2 Schematic fragment showing the current-sensing circuitry in place for thedaughter board power rails on the NB2DSK01





Accessing and Using Power Monitoring

Prior to accessing the power monitoring in Altium Designer ensure that the Desktop NanoBoard is connected to the PC (viaUSB or Parallel connection) and is powered-on

Command Central for power monitoring can be found on the instrument panel for the NanoBoard Simply double-click on the

icon for the NB2DSK01 in the Devices view (View raquo Devices View) to access the Instrument Rack ndash NanoBoard Controllers

panel (Figure 4)

Figure 4 Power monitoring is an integral part of the Desktop NanoBoards instrument panel

The controls are located in the bottom-right region of the panellabeled POWER MONITOR Use the Polling LED to essentially turn

power monitoring ON or OFF with respect to the panel

With polling enabled the window to the right presents the total power

usage across all 19 monitored power rails on the NB2DSK01 as well

as its temperature (in Degrees Celsius)

Fo each satellite board (daughter board and peripheral boards)

currently plugged into the NB2DSK01 motherboard (and presented in

the PLUGINS region of the panel) the total power usage across all

monitored power rails (routed to the corresponding docking

connector) is shown

For a more detailed look at the power monitoring landscape click on

the Show Panel button to access the Power Monitor panel (Figure

5)

Note The panel can be accessed directly from the Devices view by

right-clicking on the icon for the NB2DSK01 and choosing Show

Power Monitor Panel from the context menu

The panel gives you a breakdown of current and power values for

each monitored power line grouped by destination (daughter board

peripheral board User Header) The total power usage in each group

is also given

In addition to the total power usage across all monitored power lines

for the entire system the panel also gives a breakdown of

bull Total power usage per power supply

bull Total voltage per power supply

Figure 5 Use the Power Monitor panel to get a detailed viewof the currents drawn and the power used across all monitoredlines





bull Total current drawn per power supply

As with the instrument panel the option to enabledisable polling is provided as well as the ability to define the polling interval ndash

the period between accessing current measurements from the NanoBoard itself (more specifically the firmware on the

NanoTalk Controller) By default this value is set to be 1000ms

Unlike the instrument panel however if polling is disabled you can still

manually update the monitored information displayed within the PowerMonitor panel Remember that polling is simply the automatic retrieval

and update of monitored values The power monitoring itself ndash the

hardware on the motherboard ndash is permanently functional

Further options are available in the Power Monitor Options dialog

(Figure 6) This dialog can be accessed from both the instrument panel

and the Power Monitor panel by clicking the Options button

The dialog provides another place in which to define the polling interval

It also allows you to specify the voltage that is applied to the User

Headers This is required if you have not selected either 33V or 5V on

the NB2DSK01 itself through use of jumper placement on the

associated configurable jumper headers for User Header A (JP4)

and User Header B (JP5) respectively

If you have placed a jumper to select the voltage the setting in the

dialog should match that selection in order to gain accurate power

calculations for these lines

The dialog also offers graphing options This relates to the graphical

display of power monitoring information which is considered in the next

section

Graphical Display of Monitored Information

Display of power monitoring information in tabular format is good but a visual representation of the values over time is far more

engaging and readable To this end the power monitoring facility offers the ability to display the monitored informationgraphically

All information available in the Power Monitor panel can be enabled for display in a number of charts within Altium Designers

Sim Data Editor Use the Graphing Options region of the Power Monitor Options dialog (refer back to Figure 6) to enable the

charts required

Graphing itself is only possible provided polling is enabled Graphing can be

startedstopped in a number of ways

bull From the NanoBoards Instrument panel ndash either use the Start Graphing

button (which changes to Stop Graphing button) or the Graphing LED

to toggle graphing ONOFF

bull From the Power Monitor panel ndash use the Enable Graphing option to

toggle graphing ONOFF

Once enabled the monitored data and resulting waveforms will be written to

a Simulation Data File (sdf) and displayed within a multi-tabbed waveform

analysis window ndash presented in the Sim Data Editor

Figure 8 on the next page illustrates graphing of results for a Desktop

NanoBoard that has three peripheral boards and a daughter board attached As can be seen each chart is available on a

separate tab The active chart in this case is the Summary chart which contains two plots The first plot ndash entitled Power

Summary ndash contains waveforms for

bull The total power usage for the Desktop NanoBoard system (all 19 monitored power lines) labeled Total

bull The total power usage for the daughter board

bull The total power usage for Peripheral Board A

bull The total power usage for Peripheral Board B

bull The total power usage for Peripheral Board C

Figure 6 Setup power monitoring options as required

Figure 7 Start graphing the data for the monitoredower lines





bull The total power usage for the two User Headers

The second plot ndash entitled Temperature ndash contains a single waveform for the temperature of the system

Figure 8 Charts wave plots and waveforms all displayed in the integrated Sim Data Editor

Using the power monitoring facility you can quickly compare power usages for different hardware configurations on the Desktop

NanoBoard Figures 9 and 10 compare two configurations ndash with and without peripheral boards attached In each case the

graphical results focus on the total power consumption across the system as well as the power consumption and current drawn

for each main power rail (12V 18V 25V 33V and 5V)

Figure 9 System power and current waveforms ndash NB2DSK01 with daughter board (DB30) attached only





Figure 10 System power and current waveforms ndash NB2DSK01 with daughter board (DB30) and three peripheral boards (PB01 PB02 PB03)attached

Looking at Figures 9 and 10 we can see that addition of the peripheral boards to the system has increased the total power

consumption and that this is due to increased power on the 33V and 5V rails If we had looked across the individual peripheral

board waveforms we would have found that the board plugged into the PERIPHERAL BOARD C connector was indeed

responsible for much of the power increase The board was in fact the PB01 AudioVideo Peripheral Board which when

considering its size and larger number of on-board devices easily explains the result

The comparison can be extended to see the effect on power consumption when the physical FPGA device on the daughter

board is programmed with a design (Figure 11)

Figure 11 System power and current waveforms ndash NB2DSK01 with daughter board (DB30) and three peripheral boards (PB01 PB02 PB03)

attached A design has been downloaded into the FPGA device on the daughter board





The total power consumption for the system has as expected increased This increase is from the extra power consumed by

the 33V power rail (by the daughter board) Figure 12 shows the jump in daughter board 33V power usage at the point where

the design is downloaded into the FPGA device

Figure 12 Increase in 33V power consumption at the point where the physical FPGA device on the daughter board is programmed with thedesign

The Sim Data Editor provides a wealth of features for waveform manipulation For example you can change the display by

moving waveforms between plots and between charts You can change X and Y axes change the appearance of waveforms

and take measurements ndash either for a single waveform or between waveforms

For more information on the workings of the Sim Data Editor and the feature-rich analysis environment it has to offer refer tothe document AP0106 Working with the Sim Data Editor

For information on the Desktop NanoBoard NB2DSK01 refer to the document TR0143 Technical Reference Manual for

Altiums Desktop NanoBoard NB2DSK01

For information on the complete range of peripheral boards and daughter boards currently available and additional

documentation specific to each go to wwwaltiumcomnanoboardresources







Functionality at the Hardware-Level

Before looking at how the power monitoring functionality is accessed within the software it is worth taking a look at the

underlying hardware by which such power monitoring of the system is made possible

On the NB2DSK01 motherboard current monitoring is in place for each of the following power lines

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD A connector

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD B connector

bull 12V 18V 25V 33V and 5V lines routed to the PERIPHERAL BOARD C connector

bull 33V and 5V lines routed to the corresponding connectors for the daughter board

bull 33V or 5V line selected for use with User Header A connector

bull 33V or 5V line selected for use with User Header B connector

A total of 19 monitored power lines

In terms of hardware this monitoring is

achieved through use of a MAX4372T high-

side current sense amplifier (from Maxim)Each power line is routed to its destination

connector through a 47mΩ resistor which

serves as the external sense resistance for

the associated MAX4372T device Powered

by the NB2DSK01s 9V supply this device

provides a voltage output that is proportional

to the voltage across this sense resistance

and has a fixed gain of 20

For current passing through the 47mΩ

resistor the voltage across the devices input

is 47uVmA The output of the device is

therefore 940uVmA (applying the x20 gain)

Two low-power 12-channel 12-bit ADC devices (MAX1229 from Maxim) collect together the analog voltage outputs from all

current sense amplifiers for transmission back to the NB2DSK01s Xilinx Spartan-3 Controller FPGA (the NanoTalk Controller)

over an SPI bus

Figure 3 Schematic fragment showing the two ADC devices which pass the subsequently converted data to the NanoTalk Controller over theSPI bus and subsequent processing by the firmware

The output of each ADC which has an internal reference voltage of 25V is

ADC output = (25V4096) 940uV = 064931mAbit (=265957A full scale)

For more information on the MAX4372T and MAX1229 devices refer to the datasheets (MAX4372-MAX4372Tpdf and

MAX1227-MAX1231pdf) available at wwwmaxim-iccom

Figure 2 Schematic fragment showing the current-sensing circuitry in place for thedaughter board power rails on the NB2DSK01









panel (Figure 4)











connector) is shown



5)







is also given
































section






charts required










































































panel (Figure 4)











connector) is shown



5)







is also given
































section






charts required




























































































section






charts required


































































AP0164 Power Monitoring on the Desktop NanoBoard NB2DSK01

Documents

Transcript of AP0164 Power Monitoring on the Desktop NanoBoard NB2DSK01