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Intel PXA27X manual Power Management Integrated Circuit Requirements, nBATTFAULT, Application Note

Models: PXA27X

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Intel® PXA27x Processor Family Power Requirements

System designers can include a software-controlled threshold level detection for nVDD_FAULT to allow an optional SDRAM keep-alive capability.

7.2nBATT_FAULT

nBATT_FAULT indicates that the main battery is low or has been removed from the device, giving the PXA27x processor an indication that power will shortly cease. Until that time, the processor can operate for a limited period from a lithium/lithium manganese coin-cell backup battery, or from a super cap that can only supply the processor for a few cycles of full-run power.

In the event of nBATT_FAULT assertion, the PXA27x processor enters an emergency form of sleep, where the only handshaking is with external SDRAM memory (putting it into self-refresh mode) to ensure that memory contents are preserved if possible (obviously, the refresh current can eventually deplete the super cap or backup battery, but not as quickly as the PXA27x processor in run mode). Supporting these features must be understood at both the board-level design and by the PMIC.

Note: The PXA27x processor does not recognize a wakeup event while nBATT_FAULT is asserted.

If the system is powered from an AC main source (90 VAC to 240 VAC or equivalent) while nBATT_FAULT is asserted, that fact may be used to gate off nBATT_FAULT and its normal effects on the system. Recognition of this condition can be built into the PMIC, and a signal indicating an AC power source is active is provided from the PMIC to the PXA27x processor GPIO<0> or GPIO<1> signals.

8.0Power Management Integrated Circuit Requirements

This section provides guidelines for designing a power management integrated circuit (PMIC) for the PXA27x processor.

8.1General PMIC Characteristics

Table 9 shows the overall characteristics for a PXA27x processor PMIC.

32	Application Note

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Intel PXA27X Power Management Integrated Circuit Requirements, nBATTFAULT, General PMIC Characteristics, Application Note

Contents

Intel PXA27x Processor Family Power Requirements Application NoteApplication Note Contents Intel PXA27x Processor Family Power RequirementsContents IntroductionIntel PXA27x Processor Family Power Requirements ContentsFigures Tables1.0 Introduction 1.1 Naming ConventionsIntel PXA27x Processor Family Power Requirements Application Note2.0 Intel PXA27x Processor Power Supply Domains Table 1. External Power Supply DescriptionsIntel PXA27x Processor Family Power Requirements Application NoteApplication Note Figure 1. Intel PXA27x Processor Internal and External Power DomainsIntel PXA27x Processor Family Power Requirements 2.1 Power Domains and System Voltage/Current Requirements 2.1.1 Intel PXA27x Processor Power SuppliesIntel PXA27x Processor Family Power Requirements Application NoteTable 2. Intel PXA27x Processor Voltage Domains Sheet 1 of Intel PXA27x Processor Family Power RequirementsApplication Note Voltage2.1.2 Power Supply Configuration in a Minimal System Table 2. Intel PXA27x Processor Voltage Domains Sheet 2 ofIntel PXA27x Processor Family Power Requirements Application Note2.1.3 Modeling Intel PXA27x processor power consumption Table 3. Regulators Required to Power the Intel PXA27x Processor2.1.3.1 Intel PXA27x Processor VCCCORE Supply Current Intel PXA27x Processor Family Power Requirements2.1.3.2 Supply Current For Each Power Domain Table 4. Intel PXA27x Processor VCCCORE Supply CurrentIntel PXA27x Processor Family Power Requirements Application Note2.1.4 Default Reset Values Table 5. Intel PXA27x Processor Supply Current For Each Power DomainIntel PXA27x Processor Family Power Requirements Application Note2.2.1 Main Battery 2.2.2 Backup Battery2.2 Batteries Intel PXA27x Processor Family Power Requirements2.2.3 Battery Chargers and Main Power Table 6. Possible Backup Battery ConfigurationsIntel PXA27x Processor Family Power Requirements Application NoteFigure 2. Typical Battery and External Regulator Configuration Intel PXA27x Processor Family Power RequirementsApplication Note PXA27x Processor3.0 Intel PXA27x Processor Low Power Operating Modes Table 7. Intel PXA27x Processor Operating ModesIntel PXA27x Processor Family Power Requirements Application Note4.0 Power Controller Interface Signals Figure 3. Overview of Power Management Operating ModesIntel PXA27x Processor Family Power Requirements Application Note4.1 Power Enable PWREN 4.2 System Power Enable SYSEN / GPIO24.3 Power Manager I2C Clock PWRSCL / GPIO3 Table 8. Power Controller Interface Signals4.4 Power Manager I2C Data PWRSDA / GPIO4 4.6 On, Off, and RESET4.6.2 User-Initiated Hard Reset Input 4.5 System-Level Considerations for I2C4.8 Power Manager Capacitor Signals 4.6.3 nRESET Output from PMIC to the Intel PXA27x Processor4.7 Universal Subscriber Identity Module USIM Intel PXA27x Processor Family Power Requirements5.0 Power Mode Sequencing 5.1 Power-On5.1.1 Cold-Start Power-On and Hardware Reset Intel PXA27x Processor Family Power RequirementsApplication Note 5.1.2 Initial Power Up and Deep Sleep Exit SequenceIntel PXA27x Processor Family Power Requirements Application Note 5.1.3 Hardware Reset BehaviorIntel PXA27x Processor Family Power Requirements Application Note Intel PXA27x Processor Family Power Requirements1. The PMIC asserts nRESET Intel PXA27x Processor Family Power Requirements Power= power manager powered by VCCCORE = power manager powered by VCCBATT5.2 Sleep and Deep Sleep 5.2.1 Sleep Entry and ExitIntel PXA27x Processor Family Power Requirements Application NoteApplication Note 5.2.2 Deep Sleep Entry and ExitIntel PXA27x Processor Family Power Requirements 6.0 Dynamic Voltage Management DVM 6.1 VCCCORE Regulator and Dynamic Voltage ManagementIntel PXA27x Processor Family Power Requirements Application NoteApplication Note 6.2 Intel PXA27x Processor Voltage ManagerIntel PXA27x Processor Family Power Requirements 7.0 Fault Management 6.3 Power Manager I2C Interface7.1 nVDDFAULT 6.4 DVM Sequencing8.0 Power Management Integrated Circuit Requirements 7.2 nBATTFAULT8.1 General PMIC Characteristics Intel PXA27x Processor Family Power Requirements8.2 Features of a PMIC Table 9. General PMIC CharacteristicsIntel PXA27x Processor Family Power Requirements Application Note8.3 Programmable Voltage Control 8.3.1 DVM Control Register8.3.2 DVM Control Register Intel PXA27x Processor Family Power Requirements8.3.4 Other Aspects of an Integrated Power Controller 9.0 Summary8.3.3 DVM Control and Status Register Intel PXA27x Processor Family Power RequirementsIntel PXA27x Processor Family Power Requirements Application Note