Figure 1: XtremeDSP kit with 4 FPS units

Transcription

1 PPLICTION NOTE XtremeDSP Kit FPS Supply Specifications Jun NT Issue 2 1. Introduction Users of the XtremeDSP Kit may sometimes reach the maximum current available from the +1.5V power module used on the XtremeDSP Kit BenONE motherboard. The Virtex-II XC2V2000 and XC2V3000 parts are capable - in more demanding applications - to require more current than the maximum that can be supplied by the FPS power module. Customers with high utilization and/or high frequency designs will see the +1.5V FPS foldback or shut itself off due to the thermal limits of the device. When the FPS shuts off this wipes out the FPG configuration. 2. Background to the Power Module Options The BenONE motherboard hosts a single DIME-II daughtercard. The BenONE motherboard has the option of being fitted with one of two types of power supply modules to provide power to the BenDD daughtercard module fitted to the BenONE motherboard. The two power module options for the BenONE motherboard are: (1) FPS Fixed Power Supply (2) PPS Programmable Power Supply XtremeDSP Kits shipped by Xilinx before June 10, 2003 are fitted with 4 FPS units. Three of these provide +3.3V to specific IO banks on the module for interfacing with peripherals such as the ZBT chips. One FPS provides the +1.5V core voltage for the Virtex-II. Linear regulator on FPS unit Example of FPS Unit Figure 1: XtremeDSP kit with 4 FPS units XtremeDSP kits shipped after June 10, 2003 by Xilinx have 3 FPS units and a PPS - now used to provide the +1.5V core voltage of the Virtex-II devices in the Kit. The PPS version can source up to 15 (absolute maximum). Simple examination of the kit will highlight if a PPS unit is provided (Figure 2). NT Issue 2-09 Jun, Page 1

2 Example of PPS Unit Figure 2: XtremeDSP kit with 3 FPS and 1 PPS unit 2.1 Specifics of Current Limits FPS vs PPS The FPS unit has reduced output current capability and produces a fixed voltage output. Power supplies are configured at the time of manufacture and have a maximum output current of 7 (absolute maximum). Even though the unit is capable of supplying 7 (absolute maximum), the actual output voltage, and, more importantly, the drop from the input to the output, will limit the operating range of the unit due to its ability to dissipate the heat generated by the conversion. The following calculations can be used to calculate the max power that can be drawn. For a FPS that is supplying +1.5V to the system, under the conditions of an ambient temperature (T) of 25C and a thermal coefficient of 35C/W: P T P P = T = Iout Iout TJ T = θ = Iout ( θ xp ), 125 = 25 + (35xP J = 2.857W J + J ( VIN VOUT ) x( 5 1.5) x = m whereθ ) J = 35 C / W, T J = 125 C(max), T = 25 C For a FPS that is supplying +3.3V to the system: NT Issue 2-09 Jun, Page 2

3 P T J P TJ T = θ = T ( θ xp ), 125 = 25 + (35xP J + J = 2.857W whereθ ) J = 35 C / W, T J = 125 C(max), T = 25 C P = Iout Iout = Iout ( VIN VOUT ) x( 5 3.3) x = The PPS units use on-board DC-DC converters, and provide for dynamic adjustment of the voltages applied to the daughtercard module slot, reacting as required for different daughtercards within the DIME-II range. Each supply is capable of supplying voltages in the range +1V to +3.3V at a maximum current of 15(abs. maximum). 3. Diagnosis and Detection 3.1 How the problem manifests itself (1) Running an FPG design that draws more than on the +1.5V core supply may initially run on the board, but after a delay (dependent upon the amount of current drain over the limit) will eventually cease to function. With current draw above the limit, the FPS unit can no longer dissipate the heat it generates and will eventually shut itself off thereby loosing the FPG configuration and clearly the design as well. 3.2 How to verify the problem (1) Nallatech provides a monitor utility for monitoring temperature, current and voltage on the XtremeDSP Kit. Currently this utility provides readings for indication only and the specific accuracy of the values may not be highly accurate. However, with this utility it is possible to monitor the voltage and current demands of a running design. (Refer to section 2.3 Using the Monitor Utility ). (2) lternatively, once a design has started running there is a set of 4 Power Good LEDs for the supplies. One of these is for the core voltage of the Virtex-II (Figure 3). Once the card has been opened within FUSE this LED goes from RED to GREEN to indicate the power is good. Power good means that the power module has switched on and is reporting to the system that is it at the requested voltage and is stable. When the FPS reaches its limit this LED will briefly turn from GREEN to RED and then BCK to GREEN. The reason it comes back to GREEN is that the FPG design has stopped and so the current draw is reduced and so the FPS cools to within it s operating limits. LED nearest MCX connectorr isi for the core. Power Supplies Off Board Opened and Suppies turned on that are being used. Figure 3: Power LEDs NT Issue 2-09 Jun, Page 3

4 Note that if a power supply is not used then the power indicator for that supply will remain RED indicating it is not switched on. For example, in the XtremeDSP kit only three supplies are required and so only three of the four LEDs will change from red to green. 3.3 Using the Monitor Utility Nallatech provides the capability to read back some voltage and current readings from the power supplies on the BenONE. n example of using this ability is provided in a separate application note T Dime II Current, Temperature and Voltage monitoring capability. This utility should work with all releases of FUSE but if errors are encountered please make sure you have a recent version (FUSE CD Version 8 or above). Updates to FUSE and the XtremeDSP kit can be found on the Nallatech support lounge, (1) The Dime II Current, Temperature and Voltage monitoring capability application note is supplied as a zip file. Included in this zip file is some associated software. When the application note is extracted there is a BIN folder that contains an executable called dispdata.exe. Running dispdata will launch the monitor utility and the FUSE Probe tool (Figure 4). (2) Once the programs have loaded, open the BenONE (XtremeDSP kit) over the required interface, typically USB. Once the card has been opened you will see the card listed in the hierarchical viewer. (3) Set the clocks for your design (4) ctivate the resets to your design so the design is held in reset (5) ssign your bit files to the relevant devices and then configure them while in reset. Do not release the reset just yet. (6) Go back to the Card Monitor application and then click on Get current Card Handle you will see the module 2 and module 3 radial buttons grayed out, as these are not available in the XtremeDSP kit. (Figure 5) (7) Now, uncheck the checkboxes (Figure 5) for a. Module Temp b. FPG Temp c. Power d. Supply, SupplyB, SupplyD - Do not uncheck SupplyC as this is the FPS output we are interested in. Unchecking some of the options simply increases the speed of the reading of SupplyC. NT Issue 2-09 Jun, Page 4

5 Figure 4: Card Monitor and FUSE Probe Tools (8) In the Card Monitor application, click on start and you will see some current and voltage readings as you click on the other tabs near the top right hand corner or the application (Figure 6 and Figure 7). (9) Release the resets to your design and you will see the current rise (Figure 6and Figure 7). (10) If there is the issue with the FPS folding back you will see at the point of failure that the current will fall and stay low and the voltage will fall from 1.5V and then come back up to 1.5V. (Figure 6 and Figure 7). NT Issue 2-09 Jun, Page 5

6 Figure 5: Card Monitor Options Here the reset is released and design becomes fully active Here the FPS folds back and the FPG design is lost Figure 6: Card Monitor Running (Current) Here the FPS folds back and the FPG design is lost as the 1.5V supply switches off briefly. It recovers as the FPG design is no longer running Figure 7: Card Monitor Running (Voltage) NT Issue 2-09 Jun, Page 6

7 4. ffected XtremeDSP Kits This issue extends to the XtremeDSP Kits that were shipped by Xilinx prior to June 10, Kits shipped since June 10, 2003 include a PPS module to provide the core voltage to the Virtex-II FPG and therefore the limitation of the FPS with respect to the core supply is not an issue. The easiest way to identify the version of the kit is by simple visual inspection as the FPS unit is easily distinguishable from the PPS unit as highlighted in Figure 1and Figure vailable Solutions 5.1 Short Term Solution The performance of the FPS unit s linear regulator can be improved by cooling the linear regulator. The cooling can be provided by positioning a fan, if possible. This is clearly not an ideal solution and only noted here for information. In tests, a 25mm^2 blower fan was positioned on the FPS unit and allows for a current draw of Board Replacement/Exchange Policy Nallatech has initiated a replacement BenONE motherboard program with Xilinx. For those XtremeDSP Kit customers who feel that their use of the XtremeDSP Kit may reach the current limit of the +1.5V FPS and would like a replacement board with the PPS on the +1.5V supply, please contact Nallatech US directly. This is an exchange program and Nallatech must receive the customer s old board, prior to shipment of the new board.. Contact Dolores LaPlante in the Nallatech US s Orlando Florida office: Nallatech Inc. Suite Research Parkway Orlando Florida United States of merica Phone: Fax: d.laplante@nallatech If you have any further technical questions please contact the Xilinx Support Hotline. NT Issue 2-09 Jun, Page 7

8 6. Modification Record Date Issue # Comments 28 May, Document Introduction 6 June, Updates to enhance, (ECN364) 2003 Nallatech Ltd. ll Rights Reserved. The Nallatech name and the Nallatech logo are trademarks of Nallatech Ltd. ll other trademarks are the property of their respective owners. Nallatech Ltd. does not assume any liability arising out of the application or use of any product described herein; nor does it convey any license under its copyrights, or any rights of others. Nallatech Ltd. reserves the right to make changes, at any time, in the order to improve reliability, function, or design and to supply the best product possible. Nallatech Ltd. cannot assume responsibility for the use of any circuitry described other than circuitry entirely embodied in its products. No other circuit patent licenses are implied. Nallatech Ltd. will not assume responsibility for any circuits shown nor represent that they are free from patent infringement or of any other third-party right. Nallatech Ltd. assumes no obligation to correct any errors contained herein or to advise any user of this text of any correction if such be made. Nallatech Ltd. will not be liable for the accuracy or correctness of any engineering or software support or assistance provided to a user. NT Issue 2-09 Jun, Page 8