Advanced Sequencing and Monitoring Using the UCD9081

Application Report
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Eric Wright ........................................................................................................... PMP - Digital Power
ABSTRACT
This application report describes how to design a custom sequencing and monitoring solution using the
UCD9081. Hardware implementation details and use of the GUI are included. The application report, the
UCD9081 data sheet, and the UCD9081EVM User’s Guide provide information that can assist in the
design and implementation of custom power supply sequencing solutions.
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Contents
Power System Monitoring and Sequencing with the UCD9081 ...................................................... 3
1.1
Power Supply Monitoring ......................................................................................... 3
1.2
Power Supply Sequencing ........................................................................................ 3
1.3
Shutdown Sequencing ............................................................................................ 4
1.4
Rail Errors ........................................................................................................... 4
1.5
Alarm Processing .................................................................................................. 4
1.6
Error Logging ....................................................................................................... 4
1.7
Dependent Rails and GPOs ...................................................................................... 4
1.8
Using Multiple UCD9081 ICs ..................................................................................... 5
GUI Operation ............................................................................................................... 5
2.1
UCD9081 GUI Main Window ..................................................................................... 5
2.2
File Menu Options ................................................................................................. 8
2.3
View Menu Options .............................................................................................. 11
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices ................................... 19
3.1
Dependent Rails and GPOs .................................................................................... 19
3.2
Using Multiple UCD9081 ICs ................................................................................... 22
3.3
Error Logging ...................................................................................................... 22
Example Sequencing Design ............................................................................................ 25
Enabling and Disabling Individual Rails and GPOs Over the I2C bus .............................................. 34
System Design Considerations .......................................................................................... 37
Links to Other Useful Documents ....................................................................................... 37
1
UCD9081 GUI Main Window .............................................................................................. 5
2
Clearing Errors Logged in Flash Memory................................................................................ 7
3
File Tab From Main Window Menu Bar .................................................................................. 8
4
Save UCD9081 Parameters to Hexadecimal File ...................................................................... 9
5
Select Device Option From File Menu Tab
6
View Tab From Main Window Menu Bar ............................................................................... 11
7
System Configuration Option From View Menu Tab.................................................................. 12
8
Rail Configuration Drop-Down From View Menu Tab ................................................................ 13
9
Rail Configuration Option From View Menu Tab ...................................................................... 13
10
Flowchart for Retry 0 Times.............................................................................................. 14
11
Flowchart for Retry n Times.............................................................................................. 15
12
Flowchart for Retry Continuously ........................................................................................ 16
13
GPO Configuration Drop-down From View Menu Tab
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2
3
List of Figures
SLVU272A – December 2008 – Revised May 2010
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Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
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1
www.ti.com
14
GPO Configuration Option From View Menu Tab..................................................................... 18
15
Store User Data to the UCD9081 ....................................................................................... 19
16
Example of Dependent Rail Configuration and Processing .......................................................... 20
17
Grayed Out Dependent Rails ............................................................................................ 21
18
Option for Cascading Multiple UCD9081 ICs .......................................................................... 22
19
Error Log .................................................................................................................... 23
20
Using the GUI to Communicate With the UCD9081 in a User’s Application ...................................... 25
21
Select All Rails From Rail Configuration Drop-Down Menu
22
Example – Configure Rail 8 .............................................................................................. 27
23
Example – Configure Rail 1 .............................................................................................. 28
24
Example – Configure Rail 2 .............................................................................................. 29
25
Example – Configure Rail 3 .............................................................................................. 30
26
Example – Configure Rail 4 .............................................................................................. 31
27
Example – Configure Rail 5 .............................................................................................. 32
28
Example – Configure GPO2
29
Example – Configure Shutdown Delays for All Rails ................................................................. 33
30
USB to I2C Adapter GUI for Manual Register Reads and Writes
.........................................................
.............................................................................................
...................................................
26
33
36
List of Tables
2
1
Map User-Defined Voltage Rails to GUI Rail Naming Convention.................................................. 26
2
Rail Enable and GPO Register Information ............................................................................ 34
3
GPIOVAL Control Bit Definition for ENx and GPOx .................................................................. 34
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Power System Monitoring and Sequencing with the UCD9081
www.ti.com
1
Power System Monitoring and Sequencing with the UCD9081
The UCD9081 is a single, low-power (~3 mA at 3.3 V) integrated circuit in a 32-pin, quad-flatpack package
(RHB) that monitors and sequences up to eight independent power supplies. The voltage at each rail and
the status of each supply are reported to the user’s system via the I2C™ bus. Each of the eight
power-supply enables (ENx) and up to four general-purpose outputs (GPOx) can be configured to turn on
in proper sequence based on a combination of user-defined parameters including:
• Elapsed time after a reset or sequence event
• Time delay after another power supply reaches regulation
• Voltage of another power supply
The power supply enables and GPOs can be configured to shut down in a controlled manner at specific
times following a shutdown event.
An intuitive Windows™-based graphical user interface (GUI) provides a powerful tool for configuring the
UCD9081. The UCD9081 GUI can communicate from a personal computer USB port to the UCD9081
through a USB-to-I2C interface adapter available from Texas Instruments. A connector with the UCD9081
clock, data pins, and ground on it is necessary to take advantage of this communication capability. An
example is shown in the UCD9081EVM schematic of the UCD9081EVM user's guide (SLVU249). The
GUI can then be used to configure the UCD9081 and to monitor operation of the sequencing system.
Sequencing parameter files (*.par) developed using the EVM or on other designs can be loaded by the
GUI as a starting point for a new design. After the final sequencing configuration is complete, the GUI or
any other I2C™ master device can be used to configure the UCD9081. Alternatively, the GUI can build a
standard Intel format *.hex file that a third-party device programmer can load into the UCD9081. Additional
details can be found in the Configuring the UCD9081 section of the data sheet (SLVS813) or in the
Programming the UCD9080 application report (SLUA441).
1.1
Power Supply Monitoring
The UCD9081 has eight voltage monitor inputs (MONx) that are multiplexed to a single, 10-bit,
analog-to-digital converter (ADC). The ADC converts MONx inputs ranging from 0 volts to the ADC
reference voltage. The ADC has an internal 2.5-V voltage reference or an external reference tied to VCC
can be used. The 2.5-V internal voltage reference has an accuracy of ±150 mV, which does not provide
good enough accuracy for monitoring system voltages in most applications. If VCC is used, then the
reference voltage accuracy is as good as the accuracy of the external VCC. Detailed specifications of the
ADC total accuracy can be found in the data sheet.
The UCD9081 can monitor voltages higher than the reference voltage if a resistor divider network is used,
so that the voltages at the MONx inputs are no larger than the reference voltage. The source impedance
of the divider network must be kept below about 15 kΩ to ensure that the rise times on the internal MONx
sample-and-hold capacitor are much faster than the ADC conversion time. The data sheet provides
information about proper selection of the scaling resistors.
An I2C master can read the voltages from each MONx input. Each MONx input can be used as part of the
sequencing criteria or to trigger system alarms and cause shutdowns.
1.2
Power Supply Sequencing
The MONx voltage monitoring inputs are directly linked to power supply enable pins (ENx) and can be
configured through the GUI to control up to four general-purpose outputs (GPOx). During a sequencing
event, each ENx pin can be configured to be either active low or active high and can be configured to
assert based on a user-specified time delay following startup (Time), after a parent rail reaches regulation
(Parent (Reg)) or after a parent rail achieves a specific voltage (Parent (V)). A rail also can be monitored
without asserting the corresponding ENx pin (None). Even if None is selected for a rail, any configured
Alarm Processing will be observed.
Windows is a trademark of Microsoft Corporation.
I2C is a trademark of Philips Corporation.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
3
Power System Monitoring and Sequencing with the UCD9081
1.3
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Shutdown Sequencing
For many applications, rail shutdown order and timing is as important as startup order and timing. The
UCD9081 can be configured through the GUI to shut down each rail and GPO based on shutdown delay
times specified in milliseconds. The shutdown delay times define how long each rail or GPO waits after a
shutdown command is generated before disabling the appropriate ENx pin or GPO.
1.4
Rail Errors
Once the ENx pins have been asserted, the UCD9081 compares the rail voltages on the MONx inputs to
user settings for undervoltage (UV) and overvoltage (OV) conditions. UV and OV thresholds define the
in-regulation boundaries for the rail. If the rail voltage is within the UV and OV settings, then the rail is in
regulation.
Errors can occur at start-up if a rail does not achieve regulation within a user-specified Max Time for
Regulation (MTFR). Errors also can be flagged after regulation is achieved if a rail is outside of the UV
and OV limits for longer than the user-specified Out of Reg Time (OORW) or Glitch Width. The
UCD9081 can either record or Ignore Glitch Alarms. This choice has no impact on the monitoring or
sequencing of a rail.
1.5
Alarm Processing
When a fault is detected, even on a nonsequenced rail, the UCD9081 provides a number of Alarm
Processing options:
• Ignore – The UCD9081 takes no action when faults occur.
• Log Only – Faults are logged to on-chip memory, and no other action is taken.
• Retry n Times – The ENx pin is disabled for approximately 5 ms and then enabled again 0, 1, 2, 3, or
4 times to try and restore the power supply to regulation.
• Retry Continuously – The ENx pin is disabled for approximately 5 ms and then enabled again until
the rail either reaches regulation or the system is turned off.
• Sequence – The configured shutdown sequence is ignored in this case. All rails and GPOs are
immediately disabled, followed by initiation of a start-up sequence.
Alarm Processing options are not carried out when a dependent rail is disabled by a parent rail.
However, if any dependent rails have other rails or GPOs marked as dependents, those dependent rails or
GPOs are sequenced off. Use Retry 0 Times and the appropriate dependencies to configure the
UCD9081 to initiate a shutdown sequence in response to a fault on a specific rail.
1.6
Error Logging
The UCD9081 can log errors in two ways. All errors are stored in on-chip memory and retrieved over the
I2C bus. The error log includes a time stamp that shows the elapsed time since the UCD9081 was last
reset, the rail number, the type of error, and the voltage measured on the rail at the time of the error.
The UCD9081 Log Errors to Flash feature allows the user to log errors on critical rails to flash memory
for later review, even if power is lost. This provides a useful tool to help troubleshoot failure mechanisms.
The Flash Error Log can be read and cleared by a master I2C device using the procedure outlined in the
data sheet.
1.7
Dependent Rails and GPOs
Any monitored voltage rail can shut down any other rail or GPO according to user-specified delay times if
the monitored rail is shut down. A rail can be shut down if Retry n Times is unsuccessful at bringing it
back into regulation, or if a parent rail forces it to shut down. A rail set to Sequence causes all rails and
GPOs to shut down immediately. Although Alarm Processing options are ignored when a dependent rail is
disabled by a parent rail, other rails or GPOs selected to shut down by the dependent rail do shut down.
Cascaded dependencies and an example of dependent rail behavior are shown in Section 3.
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Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
www.ti.com
1.8
Using Multiple UCD9081 ICs
For applications that require sequencing of more than eight voltage rails, multiple UCD9081 integrated
circuits (IC) can be used, either independently but connected to a single I2C bus or by cascading devices.
When using multiple, independently configured UCD9081 ICs in a design, each device is given a unique
I2C address. The UCD9081 supports up to 16 I2C addresses. The GUI can be used to communicate
independently with each device. An example of how to cascade multiple devices is given in Section 3.
2
GUI Operation
The UCD9081 can be configured and monitored via I2C using a Windows-based GUI. The GUI can be
used with the UCD9081EVM or with a user’s design to configure all available options, such as sequencing
and shutdown order, over/undervoltage limits and timing, logging of rail errors to flash memory, and other
configurable features. It also can be used to monitor the system power by reporting current readings of
voltage and error conditions on all the rails.
A detailed description of how to use the GUI with the UCD9081EVM is given in the UCD9081EVM user’s
guide (SLVU249).
2.1
UCD9081 GUI Main Window
Figure 1. UCD9081 GUI Main Window
The GUI main window, shown in Figure 1, displays the current status and voltage of each rail. The main
window menu functions provide access for the user to input the start-up and shutdown configurations. The
GUI main window has the following areas:
• System Status – shows device errors including I2C Error, Rail Error, Device Failure, and
Parameter Csum (Checksum) Error. A filled red box (Figure 1) indicates an error. The clear buttons to
the right of each error provide a means to reset the errors.
– I2C Error – communication error between the GUI and the UCD9081.
– Rail Error – one of the monitored rails has an UV, OV or Failed to Reach Regulation error.
– Error Logs in Flash – indicates that errors have been stored in nonvolatile flash memory on the
UCD9081.
– Device Failure – the UCD9081 in question is unusable, typically because a value has been written
to an improper memory location. In most cases, the UCD9081 will detect the error and repair the
memory location.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
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GUI Operation
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– Parameter Csum Error – indicates that the user-defined configuration parameters were incorrectly
stored in the UCD9081. If the configuration file was generated using the GUI, then this error can
only be due to an interruption in communication while the parameter file was being stored to the
device. If the parameter file was created outside of the GUI, then this error can be due to a
parameter file with an incorrect or nonexistent checksum. To proceed within the GUI, clear the error
and click the Update Parameters and Sequence button again.
Statistics – I2C communication statistics. Shows number of GUI I2C Writes, Reads, and NACKs (Not
Acknowledged) events. A NACK represents an I2C communication problem. Multiple NACKs indicate a
problem with the I2C bus.
Rail Status – Shows rail error status and monitored voltage of each rail. The voltage applied to the
MONx inputs cannot exceed the ADC reference voltage. However, voltages higher than the reference
can be monitored by using resistors to reduce the MONx voltage. Actual external resistor values that
are used in the design can be entered in the Rail Configuration window shown in Figure 9. The GUI
uses the resistor values to scale the displayed voltages to match the actual rail voltages. The Pull-up
and Pull-down resistor values for a rail must be set to 0.00 if the rail voltage is applied directly to the
MONx input.
– Update Parameters and Sequence button – Updates buffer-stored GUI information input by the
user in the Rail Configuration, System Configuration, GPO Configuration or User Data windows to
device program flash memory and initiates a device sequence. This process takes less than a
second.
– Sequence button – Initiates a system sequence to a single device using current sequencing
parameters. This is accomplished by sending a sequence command (0x00) to the RESTART
(0x2F) register over the I2C bus.
– Sequence All Devices button – Initiates a system sequence to all devices on the I2C bus using
current sequencing parameters.
– Shutdown button – Shuts down all rails and GPOs according to the time delays specified in the
system shutdown configuration by writing 0xC0 to the RESTART register.
– Refresh button – Manually updates the measured voltages and errors of all monitored voltage rails
if Auto Refresh is not selected under the File menu.
Error Log – Contains error messages corresponding to errors flagged in System Status. Errors can be
logged in on-chip memory in an eight-deep FIFO located in volatile memory and displayed in the GUI
error log in black text, as shown in Figure 1. On-chip memory errors also can be read by an I2C master
device but are not retained in the UCD9081 after a power cycle. Errors read from on-chip memory by
an I2C master are removed from the FIFO, creating room to write additional errors.
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
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Figure 2. Clearing Errors Logged in Flash Memory
•
Errors are posted in the UCD9081 according to the configuration for a rail. If the user has specified
Ignore Glitches for a rail, UV and OV events shorter than OORW are not posted to the error log. If the
user has specified Ignore as the alarm response, no errors are posted to the error log for that rail. All
other alarm responses result in the error condition being logged. Due to the unknown latency of the I2C
master extracting data from the FIFO, the UCD9081 only posts to the FIFO if it has room to write. If
this FIFO is full and cannot be written to, the monitoring operation is unaffected.
The second method of error logging provides a way for users to store errors in nonvolatile or flash
memory and to review the errors after power has been removed from the UCD9081. Similar to errors
logged in on-chip memory, faults are logged for all rails that have the appropriate alarm processing
options selected. In this case, errors are posted to both the on-chip memory FIFO and the Flash Error
Log. The UCD9081 is capable of recording up to eight entries in the Flash Error Log. Errors are only
posted to the Flash Error Log if there is room to write. The monitoring operation is unaffected if the
Flash Error Log is full and cannot be written to. The Flash Error Log can only be read following a
device RESET.
An Ignore Flash Error Log checkbox is in the System Configuration window (Figure 7). If the box is
left unchecked, the UCD9081 is held in RESET after a RESTART if entries are detected in the Flash
Error Log. The device remains in RESET until the Error Log is read and cleared. If the box is checked,
the UCD9081 restarts whether or not entries are in the Flash Error Log. In applications that require
review of the Flash Error Log after a shutdown occurs on a critical rail, this box must not be left
unchecked to ensure that the user is able to review the Flash Error Log data before it is cleared. For
applications in which it is critical that the system try to restart whenever possible, check this box. Note
that if the device starts without clearing the Flash Error Log, it might be full at start-up, leaving no room
for new faults to be stored. A clear button to the right of the Error Logs in Flash indicator in the GUI
main window can be used to empty the Flash Error Log (Figure 2).
Menu bar – user can select File, View, Advanced, and Help menu items. File and View include the
primary UCD9081 configuration parameters. Later sections of this application report contain detailed
descriptions of each option.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
7
GUI Operation
2.2
www.ti.com
File Menu Options
The File menu includes the following commands:
• Load Configuration – loads a previously saved parameter (*.par) file into the UCD9081. The *.par
files contain custom user configurations saved in a proprietary TI format.
Figure 3. File Tab From Main Window Menu Bar
•
8
Save Configuration – saves the current UCD9081 configuration to a user parameter (*.par) file. The
parameter files can be loaded into the device by the user. This command can also generate a *.hex
file, which can be used to configure the UCD9081 in production, independent of the GUI.
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
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Figure 4. Save UCD9081 Parameters to Hexadecimal File
•
•
•
•
Default Configuration – loads factory-provided parameters into the UCD9081. This is a null
configuration that causes the device to do nothing at start-up.
EVM Configuration – loads example parameters into the UCD9081 for use with EVM start-up and
operation.
Save I2C Transactions – generates an ASCII text file containing configuration-specific I2C
transactions.
Auto-Refresh – refresh the window contents periodically. If not selected the window contents can be
refreshed manually by clicking the Refresh button at the bottom of the main window. The Refresh
button is unavailable when Auto-Refresh is selected.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
9
GUI Operation
www.ti.com
Figure 5. Select Device Option From File Menu Tab
•
•
•
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Discover Devices – discover all devices connected to the I2C bus. The UCD9081 address is
configurable by pulling inputs ADDR1, ADDR2, ADDR3, and ADDR4 (pins 25-28) high or low when
power is applied to the device. The I2C address is displayed at the bottom of the GUI main window.
Select Device – if multiple devices are connected to the I2C bus, this option allows the user to select
which device is currently communicating with the GUI by selecting from a list of available addresses.
Available devices are in bold and undetected addresses are grayed out.
Exit – stop the GUI application.
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
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Figure 6. View Tab From Main Window Menu Bar
2.3
View Menu Options
The View menu shown in Figure 6 includes the following commands:
System Configuration:
The System Configuration window is shown in Figure 7 and includes the following configuration options:
• Shutdown Delays – user configuration of shutdown delays for each of the eight voltage rails and four
GPOs. If a rail or GPO is marked for shutdown, then it does so according to the shutdown delays
entered here. In the case of dependent rails shut down by parent rails, the delays are measured as the
time between the event that marks a rail for shutdown and when the corresponding ENx pin is
disabled. For example, if Rail 1 has Rail 2 specified as a dependency and Rail 1 is forced to shut
down, the shutdown delay timer for Rail 2 starts when Rail 1 crosses its UV threshold (Rail 1 is
considered off).
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
11
GUI Operation
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Figure 7. System Configuration Option From View Menu Tab
•
Voltage Reference – user selection of internal 2.5V or external (VCC) 3.3V Voltage Reference for the
ADC. When VCC is selected as the reference, the GUI provides an area for the actual VCC voltage to be
entered. For example, if the actual VCC voltage measured at the device is 3.1 V, the GUI can use this
to properly scale the displayed voltages.
NOTE: When the reference is changed and stored to the GUI buffer, the displayed rail voltages are
incorrectly scaled, until the device parameters are updated using the Update Parameters and
Sequence button in the GUI main window
•
•
•
Pin Function Select – configures pin 25 as either EN8 or GPO1. The selected function disables
configuration options for the other function.
Store to Buffer and Close buttons – the Store to Buffer button saves the current window entries to a
GUI buffer. The Update Parameters and Sequence button on the GUI main window can be used to
resequence the EVM with the new configuration. The Close button closes the window. Any changes
that are made without clicking the Store to Buffer button are not stored in the device when Update
Parameters and Sequence is chosen in the main window and are lost when the System Configuration
window is closed.
Sequence Control – when this box is left unchecked, the UCD9081 stays in RESET after start-up if
entries are detected in the Flash Error Log. If the box is checked, the device starts up whether or not
entries are detected in the Flash Error Log.
Rail Configuration:
The Rail Configuration drop-down menu is shown in Figure 8. All Rails simultaneously opens all eight rail
configuration windows for comparison setup. A single Rail Configuration window is shown in Figure 9 and
includes the following configuration options:
12
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
www.ti.com
Figure 8. Rail Configuration Drop-Down From View Menu Tab
Out of Reg Time
Max time for
supply UV/OV
glitch before
alarm trigger
UV Threshold
Minimum voltage
limit
Max Time for
Regulation
Max time for
supply regulation
after sequencing
Ignore Glitch
Alarms
Select to ignore
short duration
UV/OV events
Log Errors to Flash
Store rail errors in
UCD9081 flash
memory
Sequence after
Shutdown
Sequence
system if current
rail shuts down
Voltage Divider
Resistor divider
ratios for GUI
display scaling
Active Low
Power supply enable
signal polarity
selection
Rails/GPOs to
shutdown
Rails and GPOs
dependent on
current rail
OV Threshold
Maximum voltage
limit
Sequencing Conditions
Sequencing event
trigger for each rail
Sequencing Conditions
Sequencing event
timing or voltage
threshold
Sequencing Conditions
Parent rail
designation
Alarm Processing
Action taken
following alarm
notification
Figure 9. Rail Configuration Option From View Menu Tab
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
13
GUI Operation
•
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Sequencing Conditions Selections – Voltage rail sequencing conditions are:
– None – rail is not sequenced.
– Time – time in milliseconds following a Start-up Sequence event before rail is enabled.
– Parent (Reg) – time in milliseconds to delay after the parent rail achieves regulation before
enabling the current rail.
– Parent (V) – voltage the parent rail must reach before the current rail is enabled.
Alarm Actions – The alarm actions are:
– Ignore – take no action and do not log error.
– Log Only – log any failures on this rail but take no other action, and keep rail enabled.
– Retry n Times – continue to retry this rail for a configurable number of times (n = 0,1,2,3,4), then
shut down according to the configured Rail and GPO Dependencies and the Shutdown Delays. If
Retry is selected and the UCD9081 detects a fault, the following procedure takes place (Figure 10
and Figure 11):
1. If n = 0, skip 2-5 and go to step 6.
2. The faulty rail is disabled (~5 ms).
3. The faulty rail is re-enabled.
4. The rail remains enabled for the specified MTFR. If the rail properly achieves regulation, the rail
remains enabled, and no further action is taken.
5. If the rail does not properly achieve regulation, steps 2-4 are repeated (n–1) more times.
6. If the error condition still exists after n retries, all rails and GPOs marked as dependents are
sequenced off according to the delay times specified by the current system shutdown
configuration.
If any of the dependent rails have other rails or GPOs marked as dependents, those dependent rails or
GPOs are also forced to shut down. Use Retry 0 Times and the appropriate dependencies to
configure the UCD9081 to initiate a shutdown sequence in response to a rail error.
EVALUATE RAIL /
GPO SHUTDOWN
TIMES
MONITOR
RAIL
YES
START TIMER
STILL IN
REGULATION?
NO
RAIL/GPO
SHUTDOWN TIME
REACHED?
NO
OORW
ELAPSED?
NO
YES
YES
DISABLE
RAIL/GPO PIN
YES
TRIGGER
ALARM
NO
RAILS/GPOS
DEPENDENT ON
DISABLED PIN?
YES
START TIMER
FOR SUBDEPENDENTS
NO
DEPENDENCIES?
LAST RAIL/GPO
DISABLED?
NO
YES
RAILS REMAIN
ENABLED
DEPENDENT
RAILS/GPO
SHUTDOWN
ADD SUBDEPENDENTS
TO SHUT DOWN
QUEUE
Figure 10. Flowchart for Retry 0 Times
14
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
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DISABLE RAIL
FOR 5ms &
INCREMENT
RETRY COUNT
MONITOR
RAIL
EVALUATE RAIL/
GPO SHUTDOWN
TIMES
YES
STILL IN
REGULATION?
ENABLE RAIL
START TIMER
NO
NO
START
MTFR TIMER
OORW
ELAPSED?
YES
YES
RAIL/GPO
SHUTDOWN TIME
REACHED?
RAIL ACHIEVED
REGULATION?
NO
YES
TRIGGER
ALARM
NO
YES
MTFR
ELAPSED?
DISABLE
RAIL/GPO PIN
NO
NO
YES
RETRY
COUNT = N?
RAILS/GPOS
DEPENDENT ON
DISABLED PIN?
YES
START TIMER
FOR SUBDEPENDENTS
NO
NO
YES
DEPENDENCIES?
NO
RAIL REMAINS
ENABLED
LAST RAIL/GPO
DISABLED?
ADD SUBDEPENDENTS
TO SHUT DOWN
QUEUE
YES
DEPENDENT
RAILS/GPO
SHUTDOWN
Figure 11. Flowchart for Retry n Times
•
Alarm Actions (continued)
– Retry Continuously – continue to retry this rail by disabling the rail (with ENx pin) and then
re-enabling the rail. Repeat until the power supply rail alarm clears (Figure 12).
– Sequence – shut down all rails and GPOs immediately (ignore shutdown time delays), and then
sequence-on the system according to the current start-up sequence configuration.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
15
GUI Operation
www.ti.com
MONITOR
RAIL
DISABLE RAIL
FOR 5mS
YES
ENABLE RAIL
STILL IN
REGULATION?
START MTFR
TIMER
NO
RAIL ACHIEVED
REGULATION?
NO
OORW
ELAPSED?
YES
NO
NO
MTFR ELAPSED?
YES
YES
TRIGGER
ALARM
RAIL REMAINS
ENABLED
Figure 12. Flowchart for Retry Continuously
•
•
•
•
•
•
•
16
Rail and GPO Dependencies – rails and GPOs can be marked as dependent on each other. This
affects which rails and GPOs are shut down according to an alarm response. Delays specified in the
system shutdown configuration and described in the preceding options are measured as the time
between the event that marks a rail for shutdown and when the corresponding ENx pin is disabled. For
example, if Rail 1 has Rail 2 specified as a dependency and Rail 1 is forced to shut down, the
shutdown delay timer for Rail 2 starts when Rail 1 crosses its UV threshold (Rail 1 is considered off).
If a voltage rail is disabled through a dependency on a parent rail, Alarm Processing options for the
dependent rail including Ignore, Log Only, Restart n Times, Restart Continuously, and Sequence
are not carried out. Because logging conventions are still followed, if Ignore is selected a shutdown
caused by a parent rail is not recorded in the error log. Sequence After Shutdown is implemented if
selected for a dependent rail that is disabled by a parent rail. Sequence After Shutdown is described
in detail under the Rail Configuration section later in this document.
Active Low (Polarity) – specify enable pin polarity.
UV/OV Threshold – specify undervoltage and overvoltage trip points. Note that a UV value of zero
causes the device to ignore any undervoltage conditions and that an OV value which is excessively
high causes the device to ignore any overvoltage conditions.
Out of Reg Time (ms) – specify the maximum amount of time (or glitch width) that the rail can be
outside of the UV/OV range before an alarm is declared.
Max Time for Regulation (ms) – specify the maximum amount of time a rail is allowed to achieve
regulation (rail voltage must be within the UV/OV range) before an alarm is declared.
Ignore Glitch Alarms – user can choose to not log glitches on a monitored rail
Log Errors to Flash – log rail errors to nonvolatile memory for later evaluation.
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
GUI Operation
www.ti.com
•
•
Sequence after Shutdown–specify UCD9081 ENx outputs to re-sequence the system as defined by
the current sequencer configuration if the current rail is shut down. Sequence after Shutdown is an
option that can be used with Retry n Times. If this option is used with Retry n = 0, the following
procedure takes place:
1. All rails and GPOs marked as dependents of the faulty rail are sequenced off according to the time
delays specified in the system shutdown configuration.
2. The GUI calculates the worst-case ENx or GPOx shutdown delay based on dependencies and
delay timing.
3. The UCD9081 waits until the time delay calculated by the GUI is satisfied.
4. All remaining rails and GPOs are then shut down at the same time.
5. UCD9081 RESET occurs according to the current start-up sequence configuration.
If this option is used with Retry n =1,2,3,4, the following procedure takes place:
1. The faulty rail is disabled for approximately 5 ms.
2. The faulty rail is re-enabled.
3. The rail remains enabled for the specified MTFR. If the rail achieves regulation, it remains enabled,
and the UCD9081 continues monitoring as normal. No further action is taken.
4. If the rail does not achieve regulation, steps 1-3 are repeated (n - 1) more times.
5. If the error condition still exists after n retries, all rails and GPOs marked as dependents of the
faulty rail are sequenced off according to the time delays specified in the system shutdown
configuration.
6. The GUI calculates the worst-case ENx or GPOx shutdown delay based on dependencies and
delay timing.
7. The UCD9081 waits until the time delay calculated by the GUI is satisfied.
8. All remaining rails and GPOs are then shut down at the same time.
9. UCD9081 RESET occurs according to the current start-up sequence configuration.
Note that if a rail is specified to sequence after shutdown and is also marked as a dependent in the
shutdown options of another rail, a fault on the parent rail could cause a sequence of the entire
system. For example, if Rail 1 is configured to sequence after shutdown, and Rail 2 has Rail 1
selected as a dependent, then if Rail 2 is shut down, Rail 1 shuts down and the system follows the
appropriate sequence after shutdown procedure.
Voltage Divider – specify the external voltage divider resistor values that have been used in the
design to attenuate the maximum voltage of a high voltage rail to Vref (2.5 V or 3.3 V) at the MONx pin.
The GUI uses these values to properly scale and display the voltages received through the UCD9081
monitors. If no external resistor divider is used, enter zero ohms for both resistor values to cause the
divider ratio to be evaluated as unity (no scaling).
GPO Configuration:
The GUI GPO drop-down menu is shown in Figure 13. All GPOs simultaneously opens all GPO
configuration forms for comparison setup. A single GPO Configuration window is shown in Figure 14 and
includes the following configuration options:
• Active Low – specifies GPO pin polarity
• Sequence after Shutdown – UCD9081 GPOs can be marked to re-sequence the system as defined
by the current sequencer configuration if the GPO is specified as dependent on a rail that shuts down.
• Sequencing Conditions Selections – GPO sequencing conditions are:
– None – GPO is unsequenced.
– Time – time in milliseconds following a Sequence event before GPO is enabled.
– Parent (Reg) – time in milliseconds to delay after the parent rail achieves regulation before
enabling this GPO.
• User Data – user can enter data to be uploaded to the device, such as customer-specific identification.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
17
GUI Operation
www.ti.com
Figure 13. GPO Configuration Drop-down From View Menu Tab
GPO Configuration Window
Sequence Event
Parameters for GPOs
Close
Close active GUI
window without
saving updated
parameters
Active Low
GPO polarity selection
Store to Buffer
Stores active GUI
window
configuration
parameters to buffer
for UCD9081 update
Sequence after Shutdown
Resequence GPO after
shutdown event
Sequencing Conditions
Sequencing event
trigger for each GPO
Sequencing Conditions
Sequencing event timing
or voltage threshold
Sequencing Conditions
Parent rail designation
Figure 14. GPO Configuration Option From View Menu Tab
18
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
www.ti.com
Figure 15. Store User Data to the UCD9081
3
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
3.1
Dependent Rails and GPOs
Alarm Processing options (Ignore, Log Only, Restart n Times, Restart Continuously) are not carried
out for a dependent rail if that rail is disabled through a dependency on a parent rail. Because logging
conventions are still followed, if Ignore is selected, a shutdown caused by a parent rail is not recorded in
the error log. Sequence After Shutdown is implemented if selected for a dependent rail that is disabled
by a parent rail. Sequence After Shutdown is described in detail under the Rail Configuration section
later in this document.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
19
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
www.ti.com
Figure 16. Example of Dependent Rail Configuration and Processing
20
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
www.ti.com
Although Alarm Processing options are ignored when a dependent rail is disabled by a parent rail, other
rails or GPOs selected to shut down by the dependent rail are disabled. Figure 16 shows an example with
Rail 2 as a dependent of Rail 4. In this configuration, if Rail 4 experiences a sustained UV or OV condition
longer than 5.8 ms (Out of Reg Time), then Rail 4 retries three times as described in the Retry n Times
section. If Rail 4 does not achieve regulation after the third try, then Rail 2 is shut down according to the
time delay in the System Configuration window. According to the Rail 2 Alarm Processing configuration, it
retries one time if an error is on the rail. However, because Rail 2 is shut down due to its dependency on
Rail 4 and not because of an error on Rail 2 itself, it does not retry at all. Rail 2 is configured to shut down
Rail 1, Rail 6, and GPO3, and those outputs are disabled on the shutdown of Rail 2. Rail 1, Rail 6, and
GPO3 are not configured to shut down other rails so the cascaded shutdown stops at this point.
To summarize, if Rail 4 registers a sustained error:
1. Rail 4 tries to restart three times.
2. If Rail 4 does not achieve regulation after the third try, Rail 2 shuts down 500 ms after Rail 4 shuts
down.
3. Rail 2 does not try to restart.
4. GPO3 shuts down 50 ms after Rail 2 shuts down.
5. Rail 1 shuts down 150 ms after Rail 2 shuts down.
6. Rail 6 shuts down 2500 ms after Rail 2 shuts down.
If a voltage rail is configured to Retry n Times with dependent rails that are disabled if regulation is not
achieved, and the Alarm Processing options for that rail are changed, the previous dependencies remain
checked but grayed out. If the voltage rail with the grayed-out checked dependencies is forced to shut
down by a parent rail, then the dependent rails are also shut down. For example, in Figure 17, if Rail 5 is
disabled by a parent rail, then Rail 4, Rail 7, and GPO2 are also disabled. If the user does not want such
cascaded dependencies to take effect, then the grayed-out dependencies can be cleared by doing the
following:
1. Select Retry.
2. Uncheck the boxes.
3. Re-select the required alarm processing option.
4. Click the Store to Buffer button.
Select Update Parameters and Sequence at the GUI main window.
Figure 17. Grayed Out Dependent Rails
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
21
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
3.2
www.ti.com
Using Multiple UCD9081 ICs
For applications that require sequencing of more than eight voltage rails, multiple UCD9081 ICs can be
used, either independently but connected to a single I2C bus or by cascading devices. To use multiple,
independently configured UCD9081 ICs in a design, each device is given a unique I2C address. The
UCD9081 supports 16 addresses (0x60h - 0x6Fh). The GUI can find up to 16 devices on a single I2C bus
and can be used to communicate independently with each device. Interdependencies between voltage
rails controlled by separate devices can be implemented in a number of ways.
UCD9081 ICs can be cascaded by using an ENx pin as either the RESET line or as a voltage rail input for
the next device. Figure 18 shows one example of how multiple UCD9081 ICs can be cascaded. GP02 of
the master device is configured to assert based on the status of one of the eight rails monitored by the
master device. Assertion of GP02 brings MON8 of the slave device into regulation. The slave device is
configured so that when MON8 is in regulation, the remaining rails sequence according to the
user-specified configuration. When the master GP02 is disabled, the slave device shuts down, again as
specified by the user.
VBUS
3.3 V
3.3V
Regulator
MON[1:8]
10kΩ
RST
3.3 V
0.01µF
3.3 V
Master
UCD9081
100kΩ
3.3 V
Power
Supply
1
EN
Power
Supply
2
V
OUT
1
XIN
TEST
I2C
Master
EN
EN[1:7]
ROCS
VCC
V
OUT
2
3.3V
10kΩ
3.3 V
1µF
SCL
*
*
*Power
10kΩ
3.3 V
3.3 V
3.3V
10kΩ
DNP
3.3V
VSS
SDA
EN8/
ADDR 4/ ADDR 3/ ADDR 2/ ADDR 1/
GPO 4
GPO 3
GPO 2
GPO 1
3.3V
10kΩ
10kΩ 10kΩ
DNP DNP
EN
Supply
8
EN
Power
Supply
9
EN
Power
Supply
10
V
OUT
8
Spare GPOs
1kΩ
1kΩ
1kΩ
DNP
1kΩ
3.3 V
1kΩ
M_GPO2 triggers alarm on
slave by pulling MON
16
.
below UV setpoint
M_GPO2 active high
MON[8]
MON[1:7]
10kΩ
3.3 V
RST
0.01µF
3.3 V
EN[1:7]
OUT
9
XIN
TEST
100kΩ
Slave
UCD9081
ROCS
3.3 V
V
VCC
V
OUT
10
3.3V
10kΩ
1µF
SCL
3.3 V
*
*
*Power
10kΩ
3.3 V
3.3 V
3.3V
10kΩ
DNP
3.3V
3.3V
10kΩ 10kΩ
DNP
SDA
VSS
EN8/
ADDR 4/ ADDR 3/ ADDR 2/ ADDR 1/
GPO 4
GPO 3
GPO 2
GPO 1
EN
3.3V
10kΩ
DNP
V
OUT
15
Supply
15
Spare GPOs
1kΩ
1kΩ
1kΩ
1kΩ
DNP
I2C Address = 0x62
Figure 18. Option for Cascading Multiple UCD9081 ICs
3.3
Error Logging
In addition to taking action in response to errors on specified rails, the UCD9081 can log errors in two
22
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
www.ti.com
ways. Unless a rail is configured to Ignore faults, all faults are stored in on-chip memory and can be read
by an I2C master device, including the UCD9081 GUI (Figure 19), over the I2C bus. The user can choose
to ignore Glitch Alarms or to log them for any rail. The error log includes a time stamp showing elapsed
time since the UCD9081 was last reset, the rail number, the type of error, and the voltage measured on
the rail at the time of the error.
Figure 19. Error Log
The UCD9081 recognizes and can log five different types of rail errors. Glitches can only be logged and
cannot initiate additional Alarm Processing.
1. undervoltage glitch – monitored rail voltage drops below the UV threshold and returns to regulation
before the Out of Reg Time limit is reached.
2. overvoltage glitch – monitored rail voltage increases above the OV threshold and returns to
regulation before the Out of Reg Time limit is reached.
3. sustained undervoltage – monitored rail voltage drops below the UV threshold and stays for longer
than Out of Reg Time limit.
4. sustained overvoltage – monitored rail voltage increases above the OV threshold and stays for
longer than Out of Reg Time limit.
5. failed to start – voltage rail was enabled and failed to settle between the UV and OV thresholds within
Max Time for Regulation
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
23
Dependent Rails and GPOs, Error Logging, and Cascading Multiple Devices
www.ti.com
The Log Errors to Flash feature is a tool to help troubleshoot failure mechanisms. Errors on critical rails
can be logged to flash memory for later review even if power is lost to the UCD9081, but only critical rails
should be logged. While errors are being logged, system monitoring is disabled for the 1.5 ms it takes to
write to flash. The first eight error entries are kept. Once the Flash Error Log is full, no new entries can be
added until the log is cleared. If a rail is set to Retry Continuously and to Log Errors to Flash, the Flash
Error Log can quickly fill up if that rail fails and then tries unsuccessfully to restart. Logging errors to flash
requires 5 mA for 1.5 ms at a minimum Vcc of 3.0 V. To log critical rail errors to flash during a system
shutdown, a large capacitor can be used on Vcc to hold the device on. To size the capacitor, the shutdown
timing of the critical rails and the loading and energy storage on Vcc must be considered in addition to the
UCD9081 current, timing, and minimum voltage requirements.
If error logs exist in flash memory, the UCD9081 can be configured to hold the device in RESET following
a power cycle or reset event and not allow it to restart and sequence. While the device is in RESET, it
checks for any nonzero values in the Flash Error Log. If nonzero values are found, the device stays in
RESET until the user reads and clears the error log via I2C. If a user wants failures on critical rails to be
stored for troubleshooting purposes, then selecting this mode ensures that errors logged in flash memory
are not overwritten until the flash memory is read.
Alternatively, the UCD9081 can be configured to sequence if entries are in the Flash Error Log by setting
a check box in the System Configuration window (Figure 7). If entries are in the Flash Error Log, and the
system is configured to allow sequencing, any new entries append to any existing entries. After a device
reset or power cycle, the error log time stamp returns to 000:00:00.000. The time stamp for any errors
appended to the Flash Error Log indicates the time elapsed since the last RESET. If the Flash Error Log is
already full at RESET and is not cleared, then no new entries are appended to the log. Selecting the
second mode does log errors but also allows a system to sequence and attempt to restart if errors are
caused by a power glitch on the system input voltage or by some event other than a power supply failure
that is monitored and controlled by the UCD9081.
Once the device is operating, the Flash Error Log can be cleared by a master I2C device using the
procedure outlined in the data sheet. The clear button next to Error Logs in Flash in the GUI Main
Window also clears the Flash Error Log. Performing this action does not reset the device. The read button
displays the Flash Error Log in the GUI Main Window Error Log. Flash errors are shown in red text and
on-chip memory errors are in black.
24
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Example Sequencing Design
www.ti.com
4
Example Sequencing Design
Figure 20 shows the basic pieces required to configure the UCD9081 via I2C using a Windows-based GUI.
The GUI can configure all available options such as sequencing and shutdown order, over/undervoltage
limits and timing, logging of rail errors to flash memory, and other configurable features of the UCD9081.
Once the configuration for the device is set to the user’s requirements, the GUI can convert the *.par GUI
file into a *.hex file. The UCD9081 can be configured by a host processor or with a third-party device
programmer using the *.hex file. As previously mentioned, the GUI can monitor the operation of the
sequencer by reporting current readings of voltage and error conditions on all the rails.
UCD9081
Texas Instruments
Figure 20. Using the GUI to Communicate With the UCD9081 in a User’s Application
Once the dependencies and sequencing and shutdown timings for each of the system voltage rails and
GPOs have been established by the designer, the voltage rails and GPOs can be mapped to match the
UCD9081 GUI naming convention as shown in Table 1.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
25
Example Sequencing Design
www.ti.com
Table 1. Map User-Defined Voltage Rails to GUI Rail Naming Convention
User Designation
UCD9081
GUI
Sequence-On Parameters
Sequence-Off Parameters
Active
H or L
Dependent
Outputs
Logging
3.3V_MAIN
Rail 1
First rail started – start at 0 ms
Last rail shutdown (180 ms)
L
All active voltage
rails. All active
GPOs
Ignore Glitch Alarms
Log errors to FLASH
1V
Rail 2
Start 50 ms after 1.8V (Rail 3)
reaches regulation
First rail shutdown (10 ms)
H
None
Log errors to FLASH
1.8V
Rail 3
Start 10 ms after 2.5V (Rail 4)
reaches regulation
Second rail shutdown (20 ms)
H
None
None
2.5V
Rail 4
Start 10 ms after 3.3V_MAIN
(Rail 1) reaches regulation
Fourth rail shutdown (150 ms)
L
Rail 2, 3, 4, 5,
GPO2
Log errors to FLASH
2.5V_I/O
Rail 5
Start 100 ms after 2.5V (Rail 4)
reaches regulation
Third rail shutdown (120 ms)
H
None
None
Not used
Rail 6
Not used
Rail 7
None
Log errors to FLASH
None
None
3.3V_9081 (VCC)
Rail 8
Monitor only
Monitor only
LED_SEQ_DONE_1
GPO2
Start after last rail reaches
regulation (2.5V_I/O, Rail 5)
Shut down first
Not used
GPO3
Not used
GPO4
H
To establish start-up dependencies and timing, start from the GUI main window menu bar and select View
→ Rail Configuration → All Rails (Figure 21). Configuration is done using the GUI naming convention.
Therefore, keeping track of how the system rails and outputs correspond to the GUI rails and outputs
helps reduce confusion. For this sequencing example, Table 1 also lists the Rail and GPO dependencies.
Figure 21. Select All Rails From Rail Configuration Drop-Down Menu
26
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Example Sequencing Design
www.ti.com
Choose Rail Configuration (8), and make the following selections (Figure 22). Then repeat for each rail
used in the design based on the required system operation.
Configure Rail 8 (3.3V_9081):
Figure 22. Example – Configure Rail 8
Rail Configuration (8) – Monitor UCD9081 Supply Voltage (3.3V_9081)
Set EN8 High – not connected
Active Low – Unchecked
Voltage Regulation between 3.000 V and 3.600 V
UV threshold – 3.000
OV threshold – 3.600
Maximum Glitch width = 1.6 ms
Out of Reg Time (ms) – 1.6
Supply must be within regulation 1 second after enable
Max Time for Regulation (ms) – 1000
Power supply glitches are not logged to SRAM or FLASH
Ignore Glitch Alarms – Checked
Out of regulation errors are logged to FLASH
Log Errors to Flash – Checked
Do not resequence the system after a commanded shutdown of Rail 8
Sequence after Shutdown – Unchecked
Divide rail voltage so that Rail 8 max (3.6 V) = 3.2 V at ADC
Voltage Divider Pullup – 1.00
Voltage Divider Pulldown – 8.00
Monitor Rail 8 only – do not sequence
Sequencing Conditions – None
If Rail 8 voltage falls out of regulation log error to FLASH
Alarm Processing – Log Only
If Rail 8 is shut down, do not shut down any other rails or GPOs
Rails/GPOs to shut down – Check no boxes
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
27
Example Sequencing Design
www.ti.com
Configure Rail 1 (3.3V_MAIN):
Figure 23. Example – Configure Rail 1
Rail Configuration (1) – Monitor and Sequence Input to All Other Supplies (3.3V_MAIN)
28
EN1 Low turns on 3.3-V Power Supply to rest of system
Active Low – Checked
Voltage Regulation between 3.000 V and 3.600 V
UV threshold – 3.000
OV threshold – 3.600
Maximum Glitch width = 2 ms
Out of Reg Time (ms) – 2.0
Supply must be within regulation 100 ms after enable
Max Time for Regulation (ms) – 100
Power supply glitches are not logged to SRAM or FLASH
Ignore Glitch Alarms – Checked
Out of Regulation errors are logged to FLASH
Log Errors to Flash – Checked
Do not resequence the system after a commanded shutdown of Rail 1
Sequence after Shutdown – Unchecked
Divide rail voltage so that Rail 1 max (3.6 V) = 3.2 V at ADC
Voltage Divider Pullup – 1.00
Voltage Divider Pulldown – 8.00
Enable rail immediately by setting EN1 low
Sequencing Conditions – Time 0 ms
If Rail 1 voltage falls out of regulation disable EN1 and then Retry until
regulation is achieved or system is turned off
Alarm Processing – Retry Continuously
If Rail 1 is shut down by a parent rail, also turn off Enables for all other
active rails and GPO2
Rails/GPOs to shut down – Check Rails 1, 2, 3, 4, 5,
8, GPO2
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Example Sequencing Design
www.ti.com
Configure Rail 2 (1V):
Figure 24. Example – Configure Rail 2
Rail Configuration (2) – Monitor and Sequence 1V Supply
EN2 High turns on 1-V power supply
Active Low – Unchecked
Voltage Regulation between 0.950 V and 1.050 V
UV threshold – 0.950
OV threshold – 1.050
Maximum Glitch width = 2 ms
Out of Reg Time (ms) – 2.0
Supply must be within Regulation 200 ms after enable
Max Time for Regulation (ms) – 200
Power supply glitches are not logged to SRAM or FLASH
Ignore Glitch Alarms – Checked
Out of Regulation errors are logged to FLASH
Log Errors to Flash – Checked
Do not resequence the system after a commanded shutdown of Rail 2
Sequence after Shutdown – Unchecked
Measure rail voltage directly with ADC
Voltage Divider Pullup – 0.00
Voltage Divider Pulldown – 0.00
Enable rail 50 ms after Rail 3 achieves regulation by setting EN2 high
Sequencing Conditions – Parent (Reg) 50 ms, Rail 3
If Rail 2 voltage falls out of regulation, disable EN2 and then retry until
regulation is achieved or system is turned off
Alarm Processing – Retry Continuously
If Rail 2 is shut down, do not shut down any other rails or GPOs
Rails/GPOs to shut down – Check no boxes
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
29
Example Sequencing Design
www.ti.com
Configure Rail 3 (1.8V):
Figure 25. Example – Configure Rail 3
Rail Configuration (3) – Monitor and Sequence 1.8V Supply
30
EN3 High turns on 1.8-V power supply
Active Low – Unchecked
Voltage Regulation between 1.780 V and 1.820 V
UV threshold – 1.780
OV threshold – 1.820
Maximum Glitch width = 2 ms
Out of Reg Time (ms) – 2.0
Supply must be within regulation 500 ms after enable
Max Time for Regulation (ms) – 500
Power supply glitches are logged to SRAM
Ignore Glitch Alarms – Unchecked
Out of regulation errors are not logged to FLASH
Log Errors to Flash – Unchecked
Do not resequence the system after a commanded shutdown of Rail 3
Sequence after Shutdown – Unchecked
Measure rail voltage directly with ADC
Voltage Divider Pull-up – 0.00
Voltage Divider Pull-down – 0.00
Enable rail 10msec after Rail 4 achieves regulation by setting EN3 high
Sequencing Conditions – Parent (Reg) 10ms, Rail 4
If Rail 3 voltage falls out of regulation then RESET device – immediately
disable all outputs and then sequence rails based on configured
parameters
Alarm Processing – Sequence
If Rail 3 is shut down, do not shut down any other Rails or GPOs
Rails/GPOs to shut down – Check no boxes
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Example Sequencing Design
www.ti.com
Configure Rail 4 (2.5V):
Figure 26. Example – Configure Rail 4
Rail Configuration (4) – Monitor and Sequence 2.5V Supply
EN4 Low turns on 2.5-V power supply
Active Low – Checked
Voltage regulation between 2.400 V and 2.600 V
UV threshold – 2.400
OV threshold – 2.600
Maximum Glitch width = 2.0msec
Out of Reg Time (ms) – 2
Supply must be within Regulation 500 ms after enable
Max Time for Regulation (ms) – 500
Power supply glitches are not logged to SRAM or FLASH
Ignore Glitch Alarms – Checked
Out of regulation errors are logged to FLASH
Log Errors to Flash – Checked
Sequence the system after a commanded shutdown of Rail 4
Sequence after Shutdown – Checked
Measure rail voltage directly with ADC
Voltage Divider Pullup – 0.00
Voltage Divider Pulldown – 0.00
Enable rail 10 ms after Rail 1 achieves regulation by setting EN4 low
Sequencing Conditions – Parent (Reg) 10 ms, Rail 1
If Rail 4 voltage falls out of regulation, then attempt to restart Rail 4 two
times using EN4 as described in Retry n Times
Alarm Processing – Retry 2
If Rail 4 is disabled by a parent rail or after 2 Retry attempts, turn off
Enables for Rails 2, 3, 4, 5 and GPO2
Rails/GPOs to shut down – Check Rails 2, 3, 4, 5,
GPO2
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
31
Example Sequencing Design
www.ti.com
Configure Rail 5 (2.5V_I/O):
Figure 27. Example – Configure Rail 5
Rail Configuration (5) – Monitor and Sequence 2.5V_I/O Supply
32
EN5 High turns on 2.5-V power supply
Active Low – Unchecked
Voltage regulation between 2.400 V and 2.600 V
UV threshold – 2.400
OV threshold – 2.600
Maximum Glitch width = 10 ms
Out of Reg Time (ms) – 10
Supply must be within regulation 100msec after enable
Max Time for Regulation (ms) – 100
Power supply glitches are not logged to SRAM or FLASH
Ignore Glitch Alarms – Checked
Out of regulation errors are not logged to FLASH
Log Errors to Flash – Unchecked
Do not sequence the system after a commanded shutdown of Rail 5
Sequence after Shutdown – Unchecked
Measure rail voltage directly with ADC
Voltage Divider Pullup – 0.00
Voltage Divider Pulldown – 0.00
Enable rail 100 ms after Rail 4 achieves regulation by setting EN5 high
Sequencing Conditions – Parent (Reg) 100 ms, Rail
4
If Rail 5 voltage falls out of regulation disable EN5 and then Retry until
Regulation is achieved or system is turned off
Alarm Processing – Retry Continuously
If Rail 5 is shut down, do not shut down any other rails or GPOs
Rails/GPOs to shut down – Check no boxes
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Example Sequencing Design
www.ti.com
Configure GPO2 (LED_SEQ_DONE_1):
Figure 28. Example – Configure GPO2
GPO Configuration (2) – Sequence LED_SEQ_DONE_1
GPO2 High turns on indicator LED
Active Low – Unchecked
Do not sequence the system after a commanded shutdown of GPO2
Sequence after Shutdown – Unchecked
Turn on LED 10 ms after Rail 5 achieves regulation by setting GPO2 high
Sequencing Conditions – Parent (Reg) 100 ms, Rail
5
Sequence-off timing for all rails and GPOs are set in a single window. From the GUI main window menu
bar, select View → System Configuration. Figure 29 shows the settings for this example:
Figure 29. Example – Configure Shutdown Delays for All Rails
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
33
Enabling and Disabling Individual Rails and GPOs Over the I2C bus
5
www.ti.com
Enabling and Disabling Individual Rails and GPOs Over the I2C bus
The I2C bus can be used to toggle individual UCD9081 Enables and GPOs, a capability that allows a
single rail or GPO to be turned off or on without a failure present or without sequencing the device. An
ENx or GPO can be set to 0 or 1 over the I2C bus by writing to the 2-byte GPIOVAL register. Each byte of
GPIOVAL is accessible. The address of the low byte (GPIOVALL) is 0x1Ah and the high byte
(GPIOVALH) is at 0x1Bh (Table 2). By writing to the register, any individual or group of ENx or GPOx pins
can be set. Table 3 maps the GPIOVAL register to the UCD9081 ENx and GPOx pin names. To toggle a
single or group of rails or GPOs:
1. Read GPIOVALL or GPIOVALH (returned in HEX format)
2. Invert the bit(s) for the rails or GPOs to be toggled
3. Write the new value to GPIOVALL or GPIOVALH
To toggle EN4 from 0 to 1 starting with the values given in Table 3, reading GPIOVALH returns 0x55h.
Inverting bit 11 and writing 0x5Dh back to GPIOVALH toggles EN4.
Table 2. Rail Enable and GPO Register Information
REGISTER NAME
ADDRESS
ACCESS
ADJUSTMENT AFTER ACCESS
GPIOVALL
0x1Ah
rw
+0 (0x1Ah)
GPIOVALH
0x1Bh
rw
+0 (0x1Bh)
Table 3. GPIOVAL Control Bit Definition for ENx and GPOx
GPIOVALH (0x1Bh)
GPIOVALl (0x1Ah)
ENx/GPOx
EN8
EN7
EN6
EN5
EN4
EN3
EN2
EN1
BIT
15
14
13
12
11
10
9
8
7
6
VALUE
0=logic low
1=logic high
0
1
0
1
0
1
0
1
0
0
GPO4
GPO3
GPO2
EN8/G
PO1
5
4
3
2
1
0
0
0
0
0
Texas Instruments provides a generic GUI for sending and receiving I2C commands over the USB adapter
and is useful for testing of this feature. To download and install the USB-to-I2C GUI, go to
http://focus.ti.com/docs/toolsw/folders/print/usb-to-gpio.html, click on Support Software and download
sllc288.zip, titled Reference GUIs and Libraries for Eval and Usage of the USB Interface Adapter. Open
the *.zip file and extract USB Interface Adapter GUI-v1.10.zip. If a Texas Instruments USB Interface
Adapter is being used, also extract USB Interface Adapter Driver.zip to install the required drivers.
Texas Instruments also includes an SMBus & SAA Debug Tool with the Fusion Digital Power GUI
installation (Figure 30). Using the Fusion SMBus and SAA Debug Tool
(http://focus.ti.com/docs/toolsw/folders/print/fusion_digital_power_designer.html), registers in the UCD9081
can be read or written to by entering the Device Address in decimal or hex format. For example, if the
EVM jumpers are set to “F” then the device address is “6Fh” or "111d". The device address can be found
at the bottom of the UCD9081 GUI when it is connected to an EVM or other active device. The device
address is entered into the "Target" field at the top of the GUI. Before reading or writing with the GUI, click
on the SAA Settings button and make sure that the "100kHz" button under "Bus Speed" is checked and
that "Disabled" button under "PEC (Packet Error Checking)" is checked.
34
To
•
•
•
•
•
write to the device use the "Write Data" box:
Check the "Write Byte" button
Enter the register address (1B, for example) in hexadecimal format in the Cmd box
Enter the value to be written in hexadecimal format in the Data box
Click the "Send" button
If successful "ACK" will appear under Status
To
•
•
•
read from the device use the "Read Data" box:
Check the "Read Byte" button
Enter the register address (1B, for example) in hexadecimal format in the Cmd box
Click the "Send" button
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
Enabling and Disabling Individual Rails and GPOs Over the I2C bus
www.ti.com
•
•
The value stored in the register will be reported in hexadecimal format in the Data box
If successful "ACK" will appear under Status
Figure 30 shows the value “BAh” being written to device address “111d” or “6Fh” and register address
0x1Bh. Referring to Table 2 and Table 3, EN8, EN6, EN5, EN4, and EN2 are being set to “1” and EN7,
EN3 and EN1 are being set to “0”. Writing to register address 0x1Ah allows manipulation of the GPOs.
EN8 is shown as two different bits within GPIOVAL. If EN8/GPO1 is configured as EN8, then it is
controlled by bit 8 of GPIOVALH. If EN8/GPO1 is configured as GPO1, then it is controlled by bit 1 of
GPIOVALL.
User-selected dependencies and alarm processing still apply when manipulating a single rail using I2C.
Manually disabling a rail forces a failure on that rail if the rail voltage falls below the UV threshold for that
rail. If the rail is configured to respond to a failure, then that response will be carried out.
For example, if Rail 1 is set for Retry Continuously or Retry n Times and n is not equal to 0, then if EN1 is
disabled causing Rail 1 to fall out of regulation, EN1 will be reasserted by the UCD9081. To control a
single rail without affecting the rest of the system, that rail must be configured so that no other rails or
GPOs are shut down or Alarm Processing is set to Ignore, Log Only or Retry 0. If Retry 0 is selected, then
Sequence After Shutdown cannot be selected because after the rail is disabled with no retries, then the
UCD9081 will restart. Another way to prevent Alarm Processing or disabling dependent rails or GPOs is to
set the UV threshold to 0V so that when the rail is disabled, no fault or error is flagged.
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
35
Enabling and Disabling Individual Rails and GPOs Over the I2C bus
www.ti.com
Figure 30. USB to I2C Adapter GUI for Manual Register Reads and Writes
36
Advanced Sequencing and Monitoring Using the UCD9081
SLVU272A – December 2008 – Revised May 2010
Copyright © 2008–2010, Texas Instruments Incorporated
System Design Considerations
www.ti.com
6
System Design Considerations
The UCD9081 is a stand-alone device but it does require some supporting components, such as pullup
resistors and decoupling capacitors. Also, some RESET timing and standard layout issues must be
considered. Most of this information can be found in the UCD9081 data sheet (SLVS813).
The UCD9081 operates at a relatively low frequency (8 MHz maximum) and very low power. Although
layout, routing, and decoupling requirements are not stringent, typical best practices are recommended. A
1-mF or larger decoupling capacitor must be provided as close to VCC (pin 30) and VSS (pin 1) as possible
to minimize the loop area for high-frequency supply current into the device. Each ENx output must have a
pullup or pulldown resistor that disables the power supply being controlled. When choosing the ENx
resistors, see the UCD9081 data sheet for information relating to high- and low-level output voltage and
current.
No-connect (NC) pins 4, 17, 20, and 31 and TEST pin 29 must all be tied to VSS. NC pin 2 must be left
open. All unused ENx and GPOx pins must be terminated with a pullup or pulldown resistor to force the
outputs to a known state during operation. I2C address inputs (ADDR) are read during RESET and must
have weak pullup or pulldown resistors (1 kΩ to 10 kΩ) added so that a communication address can be
established. Then, those four multiplexed pins can be used as GPOs during normal operation. I2C inputs
SCL and SDA must each have 10-kΩ pullups to VCC.
The UCD9081 package has a 3.45-mm × 3.45-mm exposed thermal pad on the board side. It is
recommended that the thermal pad be tied to Vss to improve thermal performance and to potentially
reduce EMI/EMC created by the device.
A digitally controlled oscillator (DCO) establishes the clock frequency for the device. Adding a 100-kΩ
resistor from VCC to ROSC (pin 32) reduces the DCO frequency temperature coefficient from about
–5%/°C to about –0.1%/°C.
Power-on-Reset (POR), Brownout and Reset voltage and timing requirements are given in the UCD9081
data sheet. The duration of the RESET sequence is the same whether at power up or in response to the
RST pin. During RESET, a checksum function runs to validate the user configuration memory contents. If
the configuration parameters are invalid, the last known good parameters are loaded into the device. A
checksum error extends RESET time to about 120 ms. To establish a copy of a valid configuration,
RESET takes up to 120 ms when a new configuration is first loaded. During power up, the UCD9081
begins its RESET sequence within 2 ms after VCC reaches between 1.78 V and 1.89 V. If the parameter
configuration file has not been updated since the last RESET, then RESET lasts about 35 ms. If the
parameter file is new, then RESET takes up to 120 ms to complete. Once VCC is established, if the user
wishes to generate a RESET after the UCD9081 is operational the RST pin must be held low for at least 2
ms. The UCD9081 does not respond to I2C host requests during RESET. The RESET sequence is also
described in the UCD9081 datasheet.
7
Links to Other Useful Documents
1.
2.
3.
4.
5.
6.
UCD9081, 8-Channel Power Supply Sequencer and Monitor With Error Logging data sheet (SLVS813)
Programming the UCD9081 application report (SLUA441)
Expanded System Monitoring Functions With UCD9080 application report (SLUA426)
UCD9081 Power Supply Sequencer and Monitor EVM user's guide (SLVU249)
TI-Fusion-Digital-Power-Designer GUI (SLVC118)
USB Interface Adapter Evaluation Module User’s Guide (SLLU093)
SLVU272A – December 2008 – Revised May 2010
Advanced Sequencing and Monitoring Using the UCD9081
Copyright © 2008–2010, Texas Instruments Incorporated
37
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