Si825x Multi-Phase POL-RD
Si825X MULTI-PHASE POL REFERENCE DESIGN USER ’S GUIDE
1. Kit Contents
The non-isolated Si825x Multi-Phase Point of Load (POL) Reference Design contains the following items:
40 Amp Si8250-based Multi-Phase POL Target Board
USB to SMBus
USB Debug Adapter
USB Cable
Silicon Laboratories IDE and Product Information CD-ROM. CD content includes the following:
Silicon Laboratories Integrated Development Environment (IDE)
Keil 8051 Development Tools (macro assembler, linker, evaluation C compiler)
Source code examples and register definition files
Multi-Phase POL Firmware Kernel
Application Builder tool suite (waveform editor, compensator, system and MCU wizards)
SMBus
Documentation: Kernel flowcharts and Si825x data sheet
Si825x Multi-Phase POL Reference Design User’s Guide (this document)
™
Bridge Board
TM
Monitor Software
Note: The full version of the Kernel when compiled is approximatel y 14 kB. This exceeds the 4 kB limit of the compiler that is
shipped with the kit’s software development tools. To avoid a compiler limit issue, either buy the full Keil compiler toolset
or compile the limited version of the Kernel.
Rev. 0.2 11/06 Copyright © 2006 by Silicon Laboratories Si825x Multi-Phase POL-RD
Si825x Multi-Phase POL-RD
Top View
Bottom View
Si825x
Power Supply Form Factor
Driver
SMBus Adaptor
Interface (J6)
Serial Debug Interface
C2 Connector (J7)
VIN
VOUT
DCR Current
Sense Diff Amp
2. Hardware Overview
The Si825x Multi-Phase POL Reference Design implements a digitally-controlled POL with a DPWM (digital pulse
width modulation) switching frequency of 391 kHz. The Si8250 Multi-Phase POL Target Board (Figure 1) contains
system power stages and digital control circuits with debug connectors for the Si8250 digital power controller. The
user can also access and control the target board using SMBus.
Figure 1. Si8250 Multi-Phase POL Target Board
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Si825x Multi-Phase POL-RD
Top View
Power Supply
(10–15 V, 10 A)
Electronic Load
Simulator or
Equivalent
(3.3 V, 40 A max)
VIN
+
–
VOUT
+
–
3. Si8250 Multi Phase POL Target Board Stand-Alone Operation
The POL target board comes prel oaded with firmwar e algorithm s, and is designed to provide a 3.3 V output with up
to 40 Amps of output current.
To operate the target board as a stand-alone power supply, perform the following steps:
1. Connect a V
supply on.
2. Connect a load to the V
recommended. For higher output currents, an electronic load simulator can be used.
3. Turn the V
power supply to the V
IN
terminals (J3 and J4) as shown in Figure 2. For initial testing, a 2 , 15 W resistor is
OUT
supply on. The converter will start up and provide 3.3 V at V
IN
terminals (J1 and J2) as shown in Figure 2. Do not yet turn the power
IN
OUT
Figure 2. Board Power Configuration
.
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Si825x Multi-Phase POL-RD
4. Development/Debug Operation: Initial Hardware Setup
This section describes the use of the Si8250 Multi-Phase POL Target Board with the Silicon Laboratories
integrated development environment (IDE) and Application Builder tools. To configure the hardware for connection
to the IDE:
1. Connect a V
supply on.
2. Connect the USB Debug Adaptor’s ribbon cable to the Si8250 Multi-Phase POL Target Board at J7 as shown in
Figure 3.
3. Connect the USB cable to the USB Debug Adapter’s USB input plug.
4. Connect the USB cable from the USB Debug Adapter to a USB port on the PC.
5. Turn the V
power supply to the V
IN
supply on.
IN
terminals (J1 and J2) as shown in Figure 2. Do not yet turn the power
IN
Figure 3. Overall View of the Debug Connection (Load not Connected)
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Si825x Multi-Phase POL-RD
5. Development/Debug Operation: Software Setup
The Si825x Multi-Phase POL Reference Design comes with Application Builder software (detailed in "8. Si825x
Application Builder” on page 12), a configurable real-time software Kernel, and a software Kernel compiled
specifically for the Si8250 Multi-Phase POL Target Board.
The Kernel is royalty-free application software for the Si825x family of digital power controllers that greatly reduces
application program development time, effort, and engineering risk. The Application Builder is us ed to customize
the Kernel and create C-code source level application software for the Si825x end application. The Application
Builder directly modifies the source code in the Kernel, which is then compiled and downloaded to the Si825x. For
more information on the Kernel, see application note “AN271: Si8250 Real-Time Kernel Overview”.
The Multi_Phase_POL directory (SiLabs\Power\Reference_Designs\Multi_Phase_POL\Firmware) contains the
Kernel configured for the Si8250 Multi-Phase POL Target Board.
Kernel software can be loaded/reloaded to the target board using the Silicon Laboratories IDE. Note that hardware
must be set up as detailed in "4. Development/Debug Operation: Initial Hardware Setup” on page 4. Follow the
instructions below to configure and download the Multi_Phase_POL application software for the Si8250 Multi-
Phase POL Target Board.
Note: A thorough understanding of the IDE is required before one can use the development/Debug Mode of the kit. The IDE is
detailed in "7. Silicon Laboratories Integrated Development Environment".
1. The included CD-ROM contains the Silicon Laboratories Integrated Development Environment (IDE),
Application Builder examples, the PMBus Monitor, Keil software 8051 tools, and additional documentation.
Insert the CD-ROM into your PC’s CD-ROM drive. An installer will automatically launch allowing you to install
the software or read documentation by clicking buttons on the installation panel. If the installer does not
automatically start when you insert the CD-ROM, run autorun.exe found in the root dir ectory of the CD-ROM.
Refer to the ReleaseNotes.txt file on the CD-ROM for the latest information regarding known problems and
restrictions. See "7. Silicon Laboratories Integrated Development Environment” on page 9 for further
information on the development tools.
2. Open the IDE by selecting Silicon LaboratoriesSilicon Laboratories IDE from the PC programs menu.
3. Next, the example project included with the kit is opened. Select ProjectOpen Project... from the IDE
menus. In the Project Workspace window, browse to the
“SiLabs\Power\Reference_Designs\Multi_Phase_POL\Firmware\Multi_phase_POL\Source” directory and
select the *.wsp project file. Press Open to close the window and open the project.
Note: This example will only work with the full version of the Keil compiler. If the demonstration compiler is used, use the
files in “SiLabs\Power\Reference_Designs\Multi_Phase_POL\Firmware\Multi_phase_POL_basic\Source”. This
code will compile to less than 4 kB of code.
4. The Si8250 Multi-Phase POL Target Board has several connection requirements that must be specified before
connecting to the board. Select OptionsConnection Options... from the IDE menu. In the Connection
Options window, select USB Debug Adapter in the Serial Adapter section. Next, select C2 in the Debug
Interface section. The Si825x family of devices use the Silicon Laboratories 2-wire (C2) debug interface. Click
OK to close the window.
5. Click the Connect button in the toolbar or select DebugConnect from the menu to connect to the device.
6. Build the project by clicking on the Build/Make Project button in the toolbar or by selecting ProjectBuild/
Make Project from the menu.
Note: After the project has been built the first time, the Build/Make Project command will only build the files that have
been changed since the previous build. To rebuild all files and project dependencies, click on the Rebuild All button
in the toolbar or select ProjectRebuild All from the menu.
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Si825x Multi-Phase POL-RD
7. Download the project to the target by clicking the Download Code button in the toolbar.
Note: To enable automatic downlo ading if the program build is successful, select Ena ble automatic connect/dow nload
after build in the ProjectTarget Build Configuration dialog. If errors occur during the build process, the IDE will
not attempt the download.
8. Connect a load to the V
15 W resistor is recommended. For higher output currents, an electronic load simulator can be used.
9. Run the converter firmware by pressing the “Go” button in the IDE toolbar. The converter will start up and
provide 3.3 V at V
OUT
10.Sa ve th e pr oje ct when finish e d with the debug session to preserve the current target build configuration, editor
settings, and location of all open debug views. To save the project, select ProjectSave Project from the
menu.
terminals (J3 and J4) as shown in Figure 2 on page 3. For initial testing, a 2 ,
OUT
.
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Si825x Multi-Phase POL-RD
6. PMBus Operation
PMBus is a connectivity solution designed for networking mu lti ple po wer sup plies using a sin gle mana gem ent bus.
The Real-time Kernel provided with the Si825x Multi-Phase POL Reference Design includes optional support for
PMBus. In addition, the Si825x POL design kit also comes with a PMBus Monitor application and USB to SMBus
Bridge Board to manage the power supply through PMBus.
1. The PMBus Monitor software is installed during the initial software setup. (See "5. Development/Debug
Operation: Software Setup” on page 5.)
2. Connect the board as shown in "3. Si8250 Multi Phase POL Target Board Stand-Alone Operation” on page 3.
Note that the PMBus Monitor may also be operated with the USB Debug Adaptor. If this is desired, connect the
target board as shown in "4. Development/Debug Operation: Initial Hardware Setup” on page 4.
3. Drivers must be installed to allow the PMBus Monitor to communicate with the USB to SMBus Bridge Board.
The driver files are located by default in the "Silabs\Power\Si825x AppBuilder\PMBus Monitor\USB-SMBus
Bridge Board Drivers" directory. Run the PreInstaller.exe application. This program will copy the driver files to
the PC's "Program Files" directory and then register the driver files so the board will be recognized when it is
connected. Windows Logo testing warnings may appear. Press the Continue Anyway button.
4. Connect the USB to SMBus Bridge Board to an available USB slot on your PC with a USB cable.
5. Windows will open a Found New Hardware Wizard window. Press Next after selecting the (Recommended)
option. Windows Logo testing warnings may appear. Press the Continue Anyway button. Press "Finish" to
finish installing the USB to SMBus Bridge Board.
6. Connect the Si8250 Multi-Phase POL Target Board to the USB to SMBus Bridge Board as shown in Figure 4.
Figure 4. USB to SMBus Bridge Board Connection (Load not Connected)
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Si825x Multi-Phase POL-RD
7. Open the Application Builder by selecting Silicon LaboratoriesSi825xApplication Builder from the PC
programs menu.
8. Run the PMBus Monitor application by selecting OptionsLaunch PMBus Monitor Tool from the Application
Builder. The window shown in Figure 5 will appear. The PMBus Monitor can be used to control and configure
the target board. The target can be enabled/disabled through the monitor. The PMBus Monitor allows
parameters, such as fault thresholds, to be changed. It also reports operating conditions and problems.
Figure 5. View of the PMBus Monitor
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Si825x Multi-Phase POL-RD
7. Silicon Laboratories Integrated Development Environment
The Silicon Laboratories IDE combines an editor, project manager, code development tools, and a debugger into a
single intuitive environment for code develop ment and in-system debugging. No additional target RAM, program
memory, or communications channels are required. The use of third-party compilers and assemblers is also
supported. This development kit includes the Keil Software A51 macro assembler, BL51 linker, and evaluation
version C51 C compiler. These tools can be used from within the Silicon Laboratories IDE. Figure 6 shows the IDE.
7.1. System Requirements
Silicon Laboratories IDE requirements are as follows:
Pentium-class host PC running Microsoft Windows 95 or later or Microsoft Windows NT or later.
One available USB port.
64 MB RAM and 40 MB free HD space recommended.
7.2. Assembler and Linker
A full-version Keil A51 macro assembler and BL51 banking linker are included with the development kit and are
installed during IDE installation. The complete assembler and linker reference manual can be found online under
the Help menu in the IDE or in the “SiLabs\MCU\hlp” directory (A51.pdf).
Figure 6. IDE
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Si825x Multi-Phase POL-RD
7.3. Evaluation C51 C Compiler
An evaluation version of the Keil C51 C compiler is included with the development kit and is installed during IDE
installation. The evaluation version of the C51 compiler is the same as the full professional version except, that
code size is limited to 4 kB, and the floating point library is not included. The C51 compiler reference manual can
be found under the Help menu in the IDE or in the “SiLabs\MCU\hlp” directory (C51.pdf).
7.4. Using the Keil Software 8051 Tools with the Silicon Laboratories IDE
To perform source-level debugging with the IDE, you must configure the Keil 8051 tools to generate an absolute
object file in the OMF-51 format with object extensions and debug records enabled. You may build the OMF-51
absolute object file by calling the Keil 8051 tools at the command line (e.g. batch file or make file) or by using the
project manager built into the IDE. The default configuration when using the Silicon Laboratories IDE project
manager enables object extension and debug record generatio n.
8051 Tools Into the Silicon Labs IDE”
for additional information on using the Keil 8051 tools with the Silicon
Laboratories IDE.
To build an absolute object file using the Silicon Laboratories IDE project manager, you must first create a project.
A project consists of a set of files, IDE configuration, debug views, and a target build configuration (list of files and
tool configurations used as input to the assembler, compiler, and linker when building an output object file).
The following sections illustrate the steps necessary to manually create a project with one or more source files,
build a program, and download the program to the target in preparation for debugging. (The IDE will automatically
create a single-file project using the currently open and active source file if you se lect “Build/Make Project” before a
project is defined.)
7.4.1. Creating a New Project
1. Select ProjectNew Project to open a new project and reset all configuration settings to default.
2. Select FileNew File to open an editor window. Create your so urce file(s) and save the file(s) with a
recognized extension, such as *.c, *.h, or *.asm, to enable color syntax highlighting.
3. Right-click on New Project in the Project Window. Select Add files to project. Select files in the file browser
and click “Open”. Continue adding files until all project files have been added.
4. For each of the files in the Project W indow that you wan t assembled, compiled, and linked into the target build,
right-click on the file name and select Add file to build. Each file will be assembled or compiled as appropriate
(based on file extension) and linked into the build of the absolute object file.
Note: If a project contains a large number of files, the “Group” feature of the IDE can be used to organize them. Right-click
on New Project in the Project Window. Select Add Groups to project. Add predefined groups or add customized
groups. Right-click on the group name and choose Add file to group. Select files to be added. Continue adding files
until all project files have been added.
7.4.2. Building and Downloading the Program for Debugging
1. Once all source files have been added to the target build, build the project by clicking on the “Build/Make
Project” button in the toolbar or selecting ProjectBuild/Make Project from the menu.
Note: After the project has been built the first time, the Build/Make Project command will only build the files that have been
changed since the previous build. To rebuild all files and project dependencies, click on the “Rebuild All” button in the
toolbar or select Project->Rebuild All from the menu.
2. Before connecting to the target device, several connection options may need to be set. Open the “Connection
Options” window by selecting OptionsConnection Options... in the IDE menu. First, select the adapter that
was included with the kit in the “Serial Adapter” section. Next, the correct “Debug Interface” must be selected.
Si825x family devices use the Silicon Laboratories 2-wire (C2) debug interface. Once all the selections are
made, click the OK button to close the window.
3. Click the Connect button in the toolbar or select DebugConnect from the menu to connect to the device.
4. Download the project to the target by clicking the Download Code button in the toolbar.
Note: To enable automatic downlo ading if the program build is successful, select Ena ble automatic connect/dow nload
after build in the ProjectTarget Build Configuration dia log. If errors occur during the bu ild process, the IDE will
not attempt the download.
Refer to application note “
AN104: Integrating Keil
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