Systems and methods for implementing persistent battery shutdown for information handling systems

Systems and methods are provided for implementing a persistent battery system shutdown condition when a battery pack voltage level drops below a predetermined minimum acceptable operating voltage threshold that is above a pre-determined permanent failure operating voltage threshold at which the battery pack is permanently disabled. The disclosed systems and methods may be implemented such that shutdown portion of the power-consuming components of the information handling system are not allowed to be restarted until external power has been first provided and applied to at least partially recharge the battery cells of the battery pack to a battery voltage level that is above the minimum acceptable operating voltage threshold and/or when sufficient external power is applied to power the information handling system and at the same time charge the battery cells of the battery pack.

FIELD OF THE INVENTION

This invention relates generally to information handling systems, and more particularly to persistent battery shutdown for information handling systems.

BACKGROUND OF THE INVENTION

Examples of portable information handling systems include notebook computers, tablet computers and smart phones. These portable electronic devices are typically powered by rechargeable battery pack systems such as lithium ion (“Li-ion”) or nickel metal hydride (“NiMH”) battery packs. Such battery packs are typically equipped with a battery management unit (BMU) that monitors voltage or state of charge of the battery cells of the battery pack, and that controls flow of charge current to battery cells of the battery pack and flow of discharge current from the battery based on this monitored battery cell voltage. Such battery packs are also typically equipped with a fuse that is controlled by the BMU to permanently disable the battery pack from supplying current to the information handling system for a number of possible reasons, including if the monitored battery cell state of charge ever becomes low enough to damage the battery cells or if the monitored battery cell state of charge ever drops below a pre-determined permanent failure operating voltage or capacity threshold. In modern battery packs, when the battery cells reach such a critical low voltage or capacity threshold, a permanent failure (PF) flag is set, and the BMU will blow the fuse the next time external AC adapter power is present. This is done for safety reasons to prevent further operation of the information handling system at low battery charge levels which may be damaging to the battery cells and/or which may indicate a battery cell failure.

To avoid dropping below low cell voltage and/or to avoid overdischarge stress (and the resulting permanent disablement of the battery pack by the BMU) under normal battery pack operating conditions, the BMU and/or operating system (OS) of the typical information handling system shuts off or reduces current flow from the battery pack to the information handling system at a battery voltage level that is above the permanent failure operating voltage threshold. In the OS case, the OS monitors the current voltage of the battery pack battery cells that is reported to the OS by the BMU or receives an alert from the BMU when a pre-established threshold has been crossed. Either way, the BMU and/or OS react to the value of the monitored battery voltage level by individually shutting down power-consuming components (load) of the information handling system or by shutting down flow of current to the information handling system from the battery pack when the monitored battery voltage drops below a pre-determined minimum acceptable operating voltage threshold that is set above the pre-determined permanent failure operating voltage threshold. When current draw from the information handling system is shutdown in this manner, the charge level or voltage of the battery cells of the battery pack may recover under no load conditions to a voltage that is equal to or higher than the minimum acceptable operating voltage threshold. When this occurs, the OS and/or BMU will allow the power-consuming components of the information handling system to be restarted until the monitored battery voltage once again drops below the minimum acceptable operating voltage threshold, and further reducing the amount of voltage “cushion” above the absolute permanent failure operating voltage threshold at which the BMU permanently disables the battery pack.

SUMMARY OF THE INVENTION

Disclosed herein are systems and methods for implementing a persistent system shutdown condition at a battery pack voltage (e.g., predetermined minimum acceptable operating voltage threshold) that is above a pre-determined permanent failure operating voltage threshold at which the battery pack is permanently disabled. In contrast to the reactive manner in which power-consuming components of information handling systems are conventionally shut-off below a minimum acceptable operating voltage threshold, the disclosed systems and methods may be implemented to effect a persistent shutdown of at least a portion of the power consuming components of an information handling system when battery pack voltage drops below a predetermined minimum acceptable operating voltage threshold. Because the shutdown is persistent, the shutdown power-consuming components of the information handling system are not allowed to be restarted (turned on) in one embodiment until external power has been first provided and applied to at least partially recharge the battery cells of the battery pack to a battery voltage level that is above the minimum acceptable operating voltage threshold. Additionally, the shutdown power-consuming components of the information handling system may also be allowed to be turned on when sufficient external power (e.g., from AC adapter) is applied to power the information handling system and charge the battery cells of the battery pack.

The disclosed systems and methods may be implemented in one embodiment to avoid reaching a pre-determined permanent failure operating voltage threshold that results in permanent disablement of a battery pack. However, other advantages that may be additionally or alternatively realized using embodiments of the disclosed systems and methods include, but are not limited to, reducing time required to recharge from low cell voltage recovery mode (also called pre-charge mode) and/or minimizing any cell performance degradation associated with discharge below normal shutdown (and above permanent fail condition.)

In one exemplary embodiment, the disclosed systems and methods may be implemented by setting at least one shutdown flag in persistent memory that indicates a system state exists in which the battery pack voltage has dropped below a predetermined minimum acceptable operating voltage threshold value resulting in shutdown of one or more power consuming components (e.g., system load) of an information handling system, e.g., by an OS of the system. Presence of this shutdown flag in persistent memory prevents system restart (e.g., by the OS) until the shutdown flag is removed. In this regard, this shutdown flag will remain in persistent memory until external power has been first provided and applied to at least partially recharge the battery cells of the battery pack to a battery voltage level that is above the minimum acceptable operating voltage threshold and/or when sufficient external power (e.g., from AC adapter) is applied to power the information handling system and at the same time charge the battery cells of the battery pack.

In another exemplary embodiment, it is possible that an information handling system may be optionally configured such that the OS of the system shuts down power consuming components of the information handling system when the current (e.g., real time) monitored battery cell voltage drops below an OS minimum acceptable operating voltage threshold value, and that the BMU of the system separately shuts down power current flow from the battery pack when the current monitored battery cell voltage drops below a BMU minimum acceptable operating voltage threshold value that is lower than the OS minimum acceptable operating voltage threshold value but that is above the pre-determined permanent failure operating voltage threshold at which the BMU is configured to permanently disable the battery pack, e.g., by blowing a fuse in the current path between the battery pack and the power consuming components of the information handling system. In such an optional embodiment, different shutdown flags may be set in persistent memory, an OS shutdown flag upon occurrence of the OS shutdown and a BMC shutdown flag upon occurrence of a BMU shutdown. Where an embedded controller (EC) is also present, an additional separate EC shutdown flag may also be set in persistent memory when the current monitored battery cell voltage drops below an EC minimum acceptable operating voltage threshold value that is lower than the OS minimum acceptable operating voltage threshold value but that is above the BMU minimum acceptable operating voltage threshold value.

In one respect, disclosed herein is an information handling system, including: one or more battery cells configured to be coupled to receive current from an external power source for recharging the battery cells; a system load including power consuming circuitry coupled to selectably receive current from the external power source, the battery cells, or a combination thereof, the system load including one or more processing devices; persistent memory; and persistent shutdown management circuitry including at least one of the processing devices coupled to the persistent memory. At least one of the processing devices may be configured to monitor the current charge level of the battery cells, and at least one of the processing devices may be configured to execute an operating system thereon and to initiate shut down of the operating system and disconnection of at least a portion of the system load from the battery cells when the monitored battery charge level is below a predetermined minimum acceptable operating voltage threshold value. The persistent shutdown management circuitry may be configured to: store a persistent shutdown indication in the persistent memory upon the occurrence of a shutdown of the operating system and the disconnection of at least a portion of the system load from the battery cells due to a monitored battery charge level that is below the predetermined minimum acceptable operating voltage threshold value; determine the presence of available power from the external power source and determine whether the persistent shutdown indication is stored in the persistent memory; if the persistent shutdown indication is determined to be stored in the persistent memory then allow one or more of the processing devices to reconnect the system load to the battery cells and to restart the operating system only if available power from the external power source is determined to be present for providing current to recharge the battery cells; and if the persistent shutdown indication is determined to be stored in the persistent memory then only clear the persistent shutdown indication from persistent memory if available power from the external power source is determined to be present for providing current to recharge the battery cells.

In another respect, disclosed herein is a method for implementing persistent battery shutdown for an information handling system. The method may include providing an information handling system that itself includes: one or more battery cells configured to be coupled to receive current from an external power source for recharging the battery cells, system load including power consuming circuitry coupled to selectably receive current from the external power source, the battery cells, or a combination thereof, the system load including one or more processing devices, persistent memory, and persistent shutdown management circuitry including at least one of the processing devices coupled to the persistent memory. The method may further include: 1) using at least one of the processing devices to monitor the current charge level of the battery cells; using at least one of the processing devices to execute an operating system thereon and to initiate shut down of the operating system and disconnection of at least a portion of the system load from the battery cells when the monitored battery charge level is below a predetermined minimum acceptable operating voltage threshold value; and 2) using the persistent shutdown management circuitry to: store a persistent shutdown indication in the persistent memory upon the occurrence of a shutdown of the operating system and the disconnection of at least a portion of the system load from the battery cells due to a monitored battery charge level that is below the predetermined minimum acceptable operating voltage threshold value, determine the presence of available power from the external power source and determine whether the persistent shutdown indication is stored in the persistent memory, if the persistent shutdown indication is determined to be stored in the persistent memory then allow one or more of the processing devices to reconnect the system load to the battery cells and to restart the operating system only if available power from the external power source is determined to be present for providing current to recharge the battery cells, and if the persistent shutdown indication is determined to be stored in the persistent memory then only clear the persistent shutdown indication from persistent memory if available power from the external power source is determined to be present for providing current to recharge the battery cells.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1is a block diagram of an information handling system200(e.g., portable information handling system such as notebook computer, MP3 player, personal data assistant (PDA), cell phone, smart phone, cordless phone, tablet computer, etc.) as it may be configured according to one exemplary embodiment of the disclosed systems and methods. As shown inFIG. 1, information handling system200of this exemplary embodiment includes a processor205such as an Intel Pentium series processor, an Advanced Micro Devices (AMD) processor or one of many other processors currently available. Processor205may be configured to execute an operating system (OS) such as Windows-based operating system, Linux-based operating system, etc. A graphics/memory controller hub (GMCH) chip210is coupled to processor205to facilitate memory and display functions. System memory215and a display controller220are coupled to GMCH210. A display device225(e.g., video monitor) may be coupled to display controller220to provide visual images (e.g., via graphical user interface) to the user. An I/O controller hub (ICH) chip230is coupled to GMCH chip210to facilitate input/output functions for the information handling system. Media drives235are coupled to ICH chip230to provide permanent storage to the information handling system.

Still referring toFIG. 1, an expansion bus240is coupled to ICH chip230to provide the information handling system with additional plug-in functionality. Expansion bus240may be a PCI bus, PCI Express bus, SATA bus, USB or virtually any other expansion bus. Input devices245such as a keyboard and mouse are coupled to ICH chip230to enable the user to interact with the information handling system. An embedded controller (EC)280running system BIOS is also coupled to ICH chip230. Persistent storage211(e.g., embedded and partitioned flash memory, Electrically Erasable Programmable Read Only Memory—EEPROM, etc.) is coupled to EC280for storing persistent information such as shutdown flags described further herein.

In the particular embodiment ofFIG. 1, information handling system200is coupled to an external source of power, namely AC mains250through AC adapter255. It will be understood that external power may be alternatively provided from any other suitable external source (e.g., external DC power source) or that AC adapter255may alternatively be integrated within an information handling system200such that AC mains250supplies AC power directly to information handling system200. As shown AC adapter255is removably coupled to, and separable from, battery charger/power circuit260of information handling system200at mating interconnection terminals290and292in order to provide information handling system200with a source of DC power to supplement DC power provided by battery cells of a battery system in the form of smart battery pack265, e.g., lithium ion (“Li-ion”) or nickel metal hydride (“NiMH”) battery pack including one or more rechargeable batteries and a BMU that includes an analog front end (“AFE”) and microcontroller. Further, a battery system data bus (SMBus)281is coupled to smart battery pack265to provide battery state information, such as battery voltage and current information, from BMU266of smart battery pack265to EC280and to other components such as processor205. Battery charger/power circuit260of information handling system200may also provide DC power for recharging battery cells of the battery system265during charging operations.

When a battery system of a portable information handling system is optionally provided as a replaceable battery pack, it may be configured for insertion and removal from a corresponding battery pack compartment defined within the chassis of the information handling system (e.g., such as a notebook computer), and may be provided with external power and data connector terminals for contacting and making interconnection with mating power connector terminals and data connector terminals provided within the battery pack compartment to provide power to the system load (i.e., power-consuming components) of the information handling system and to exchange data with one or more processing devices of the information handling system.

For example, as shown for the exemplary embodiment ofFIG. 2, replaceable smart battery pack265may be removably coupled to, and is separable from, other system components267of information handling system200at a terminal node by engagement of system side electrical power terminals360,394with battery pack side electrical power terminals362,396(operational electrical contact). In this regard, smart battery pack265may include battery cell circuitry324coupled to electrical power terminals362that are configured to be removably coupled to system side electrical power terminals360so that terminals360contact terminals362to allow current to be interchanged between smart battery pack265and other system components267of information handling system200. Battery cell circuitry324may be any type of rechargeable battery cell/s or combination thereof that is suitable for recharging. Examples of such battery cells include, but are not limited to, Li-ion battery cells, NiMH battery cells, nickel cadmium (NiCd) battery cells, lithium-polymer (Li-polymer) battery cells, etc.

Battery pack265also includes SMBus terminals352that are configured to be removably coupled to system side SMBus terminals350to allow data to be interchanged between smart battery pack265and EC280. A logic control circuit398is also present to control and convey battery cell status information to BMU266from battery cell circuitry324, and to convey control signals from BMU266to switching circuitry that is coupled between battery cell circuitry324in a manner that will be described further herein. It will be understood that functions of EC280may alternatively be performed by a keyboard controller in other embodiments. Also shown inFIG. 2are switching elements310and312which are each controlled by EC280, and which may be present to regulate current flow from charger260and to regulate current flow to system load320, respectively. In this regard, system load320may comprise system components other than EC280and BMU266, such as display225, processor205, media drives235, etc. ofFIG. 1. In other embodiments, system load may include at least one processing device configured to execute an OS along with additional, fewer or alternative system components that draw current. It will be understood that any other number and/or type of switching elements suitable for controlling current flow between charger260, system load320and/or battery pack265may be present. Examples of types of suitable switching elements include, but are not limited to, bipolar junction transistors (BJTs) and field effect transistors (FETs).

Smart battery pack265is also shown provided with battery current control circuitry to control flow of charge current to battery cell circuitry324of battery pack265, and to also control flow of discharge current from battery cell circuitry324of battery pack265. In this exemplary embodiment, the charge and discharge circuitry includes two field effect transistors (“FETs”)380and382coupled in series between battery charge terminal362and battery cell circuitry324. FET380is a charge FET switching element that forms a part of a charge circuit that is controlled by components (e.g., microcontroller and/or AFE) of BMU266to allow or disallow charge current to the battery cell circuitry324, and FET382is a discharge FET switching element that forms a part of discharge circuit that is controlled by components (e.g., microcontroller and/or AFE) of BMU266to allow or disallow discharge current from the battery cell circuitry324. Body diodes may be present across the source and drain of each FET switching element, i.e., to conduct charge current to the battery cell/s when the discharge FET switching element382is open, and to conduct discharge current from the battery cell/s when the charge FET switching element380is open. It will be understood that battery current control circuitry of battery pack265may include any other number and/or type of charge and discharge switching elements suitable for performing the current control tasks described herein. Examples of types of suitable switching elements include, but are not limited to, bipolar junction transistors (BJTs) and field effect transistors (FETs).

During normal battery pack operations both charge and discharge FET switching elements380and382are placed in the closed state by BMU266, which also monitors voltage of battery cell circuitry324. If BMU266detects a battery over-voltage condition, BMU266opens the charge FET switching element380to prevent further charging of the battery cell/s until the over-voltage condition is no longer present. Similarly, if BMU266detects a battery under-voltage (or over-discharge) condition in which monitored battery voltage drops below a predetermined safe shut off voltage threshold for EC280, BMU266opens the discharge FET switching element382to prevent further discharging of the battery cell/s from battery pack265until the under-voltage condition is no longer present. As will be further described herein, BMU266may also shut itself down to prevent further battery cell drain if BMU266detects that monitored battery voltage has dropped below a predetermined safe shut off voltage BMU266that is lower than the predetermined safe shut off voltage threshold for EC280. BMU266may also open the charge FET switching element214when the battery pack is in sleep mode. A current sense resistor390is present in the battery pack circuitry to allow BMU266to monitor charge/discharge current to/from the battery cell/s.

A disable fuse212is coupled in the input/output path from with battery pack side electrical power terminal362such that when blown, the battery pack265is permanently disabled. A micro-controller within the BMU266is configured to provide a control signal to the disable fuse206that will cause the fuse to be blown, e.g., in the event of a battery system failure detection (such as over-voltage charging or overloading, under voltage below a pre-determined permanent failure operating voltage threshold) or a battery cell failure detection. Further information on other possible BMU, battery pack and battery charging operations may be found in U.S. Pat. Nos. 7,378,819 , 7,391,184 , 7,619,392, and 8,138,722, each of which is incorporated herein by reference in its entirety.

It will be understood that the particular configuration of components inFIGS. 1 and 2is exemplary only and that other configurations of fewer, additional and/or alternative components are possible as are appropriate for a given particular type of battery-powered portable information handling system. It will also be understood that, when present, processing devices (such as processor205, EC280and BMU266) may be communicatively coupled in signal communication with each other using any type of data communication bus or other type of signal communication technology suitable for transferring data therebetween. Moreover, the tasks of such processing devices may be implemented separately or together using any combination of one or more suitable processing devices, e.g., such as central processing unit (CPU), controller, microcontroller, processor, microprocessor, field programmable gate array (FPGA), application specific integrated circuit (ASIC), etc.

FIG. 3illustrates one exemplary embodiment of methodology300for implementing persistent battery shut-off for an information handling system as it may be implemented by persistent shutdown management (PM) circuitry for any type of battery powered information handling system having at least one processing device configured to execute an operating system (OS). Methodology300may be implemented with information handling systems having CPU, embedded controller (EC) and battery management unit (BMU) such as notebook computers or may be implemented with information handling systems having only a BMU and no EC, such as smart phones and tablet computers. It is also possible that methodology300may be implemented with a system having only a single processing device. In any case, any one or more processing devices (EC, BMU and/or CPU) of an information handling system may be configured alone or in combination as a persistent shutdown management circuitry that includes persistent memory such as persistent storage211.

Methodology300starts in step302with information handling system powered up in normal operating mode (e.g., S0 power state) and executing the operating system (OS). In step302, the persistent shutdown management circuitry (e.g., including EC, BMU and/or CPU) monitors current battery charge level to determine if the battery charge level has dropped below a predetermined minimum acceptable operating voltage threshold value, e.g., that is set at an operating voltage threshold value in which sufficient charge level remains in the battery to allow system restart. As long as the current battery charge level is not below the minimum acceptable operating voltage threshold, the information handling system remains powered up in normal operating mode and executing the operating system (OS). However, once the monitored battery charge level has dropped below a predetermined minimum acceptable operating voltage threshold value, then OS shuts down together with one or more other power-consuming components of the information handling system to conserve battery power in step304as shown. At this point the processing device/s implementing the persistent shutdown management circuitry remains active and stores a persistent shutdown flag in persistent memory in step306. Upon every attempted reboot of the system (e.g., initiated by a user or by one or more component/s of the information handling system), the persistent shutdown management circuitry checks for the presence of such a persistent shutdown flag in persistent memory and, if such a shutdown flag is present, will not allow the system to proceed to reboot until the flag is cleared.

In step308, the persistent shutdown management circuitry monitors for the presence of external power (e.g., from an AC adapter, car charger, airplane charger, etc.), and proceeds to step313if it is detected that power has been applied to the system. Then methodology300proceeds to step314where the persistent shutdown management circuitry determines if sufficient external power exists to power the information handling system in normal operating state (e.g., S0 power state) and at the same time charge the system battery. If so, then the persistent shutdown flag is cleared from persistent memory in step321and the system is allowed to reboot with the OS in step323. However, if insufficient external power exists to power the information handling system in normal operating state together with charging the system battery, methodology300proceeds to step316where the battery is charged with external power. While charging occurs, the persistent shutdown management circuitry monitors the state of charge of the battery in step318until it is determined that the current battery state of charge is not below the predetermined minimum acceptable operating voltage threshold value, at which time the persistent shutdown flag is cleared from persistent memory in step321and the system is allowed to reboot with the OS in step323as shown.

If no external power is provided in step308, then persistent shutdown management circuitry determines in step309if the current battery charge state is below a predetermined safe shut off voltage threshold for the processing device/s that implement the persistent shutdown management circuitry, and these processing device/s are shutdown in step311once the battery charge state is found to be below this threshold. The system then remains in shutdown state (e.g., G2 or G3 power state) until power is reapplied in step315and the processing device wakes up to implement the persistent shutdown management circuitry in the power applied state313previously described.

FIG. 4illustrates one particular exemplary embodiment of methodology400for implementing persistent battery shut-off for an information handling system that includes multiple processing devices, e.g., such as processor205, EC280and BMU266, of the information handling system200ofFIGS. 1-2. However, it will be understood that methodology400may be implemented with any other configuration of battery-powered information handling system to control current supplied from one or more battery cells to one or more power consuming components of the information handling system.

Methodology400starts in step402where the operating system (OS) executing on processor205initiates and forces a system shutdown (e.g., via EC280and switching element312) based on a monitored current battery voltage of battery pack265reported to processor205by BMU266that has dropped below a predetermined minimum acceptable operating voltage threshold value that is stored, e.g., in main memory215. Such a predetermined minimum acceptable operating voltage threshold value may be selected based on a given situation (e.g., in one exemplary embodiment a battery cell voltage that corresponds to about 5% remaining battery cell capacity), but is above the respective predetermined safe shut off voltage threshold values for EC280and BMU266. Prior to this shutdown, a user may be given warning by the OS that a system shutdown is imminent absent application of external power.

Upon OS-initiated system shutdown in step402, one or more processing devices configured to operate as persistent shutdown management circuitry determine or detect in step404that an OS-initiated system shutdown due to low battery state has occurred in step402. In the illustrated embodiment ofFIGS. 1-2, EC280and BMU266may each be configured to simultaneously operate to manage persistent shut-off methodology400for system200as further described herein, although any one or more processing devices may be alternatively or additionally configured to operate as persistent shutdown management circuitry, e.g., such as a power management integrated circuit (PMIC), etc. In the illustrated embodiment, an OS-initiated system shutdown event may be communicated from the OS executing on processor205to each of EC280and to BMU266. In response to the OS-initiated system shutdown event, EC280may disconnect power from system load320of system200, e.g., by opening D-FET312.

Upon determining that an OS-initiated system shutdown has occurred, each of the persistent shutdown management circuitry may store a persistent off state indication in persistent memory in step406. For example, in the exemplary embodiment ofFIGS. 1-2, EC280may store a persistent OS off shutdown flag in persistent storage211, and also send the persistent OS shutdown flag to BMU266for storage in BMU non-volatile memory that is coupled to BMU. Alternatively, a persistent OS off shutdown flag may be stored in a common location that is accessible by both EC280and BMU266, e.g., such as BMU non-volatile memory where BMU266may access the flag in memory even when EC280is shutdown. Similar flag storage operations may be employed for other optional persistent shutdown flags such as persistent EC shutdown flag and/or persistent BMU shutdown flag. It will be understood that a persistent shutdown flag/s may be alternatively or additionally stored in these or any other suitable type/s of persistent memory by other designated persistent shutdown management circuitry processing devices, e.g., such as a power management integrated circuit (PMIC), etc.

As will be described further herein, the persistent shutdown management circuitry (such as EC280and/or BMU266) will not allow the system200to attempt a re-boot to the OS until the persistent OS shutdown flag is removed (or cleared) from persistent memory. In this regard, a persistent OS shutdown flag will not be cleared until the persistent shutdown management circuitry detects that external power is provided to system200from an external source (e.g., AC adapter255) that is capable of both powering the system load320of system200and charging battery cells of battery pack265, or upon detecting that the battery cells of battery pack265have been recharged to a sufficient charge level for powering the system load of system200in combination with a connected external power source that is alone not capable of powering the system load320of system200but that is capable of power the system load320of system200in combination with power from the battery cells of battery pack265while at the current charge level.

In one exemplary embodiment, persistent shutdown management circuitry processing device/s such as EC280and BMU266may remain active in a low power mode (e.g., using aggressive power management if available to save power) after storing the persistent OS shutdown flag in persistent storage, for as long as the current monitored charge level of battery pack265does not drop below a respective predetermined safe shut off voltage threshold for either of EC280or BMU266(i.e., the respective threshold charge value below which EC280or BMU266completely powers down). In this regard, the predetermined safe shut off voltage threshold for EC280is typically set at a higher value of battery charge than the predetermined safe shut off voltage threshold for BMU266such that EC280shuts down before BMU266shuts down as the voltage level of battery pack265drops over time. Each of the safe shut off voltage thresholds for EC280and BMU266are in turn greater than a pre-determined permanent failure operating voltage threshold for battery pack265, at which BMU266permanently disables the battery pack265by blowing disable fuse212.

Still referring toFIG. 4, EC280acting as one of the persistent shutdown management circuitry processing devices (e.g., while operating in lower power mode) is configured to determine whether external power (e.g., from AC adapter255) is being provided to information handling system200. If not, then EC280checks in step410whether the current charge level of battery pack265is below the predetermined safe shut off voltage threshold for EC280. If not, then methodology400loops back to step408as shown and repeats. However, if the current charge level of battery pack265is found in step410to be below the predetermined safe shut off voltage threshold for EC280, then the BMU266may be configured to shut down and disconnect power from EC280and the motherboard in step412, leaving only BMU266of battery pack265powered and disconnected from the remainder of the system200. A persistent EC shutdown flag may be stored in persistent memory at this time by either of EC280and/or BMU266.

As shown, BMU266then monitors in step414whether the current charge level of battery pack265is below the predetermined safe shut off voltage threshold for BMU266. If not, then methodology400loops back to step408as shown and repeats. However, if the current charge level of battery pack265is found in step414to be below the predetermined safe shut off voltage threshold for BMU266, then BMU266shuts down in step416, leaving battery cells of battery pack265disconnected from external load and in self discharge until such time that external power is provided to system200(e.g., from AC adapter255or any other suitable power source) in step420as shown. A persistent BMU shutdown flag may be stored in persistent memory at this time by BMU266. Once a power applied condition of step420is detected, then methodology400proceeds as described further herein.

Returning now to step408, as long as EC280is operating, it continues to monitor for the presence of external power in step408in the manner previously described. Upon detecting that power is applied in step408(e.g., by AC adapter255), methodology400proceeds to step420and then on to step422where BMC266and EC280wake up (i.e., if not already awake) upon detection of the application of available external power, and BMU266determines battery cell health in step424by determining if current charge level (voltage) of battery cells of battery pack265is greater than a pre-determined permanent failure operating voltage threshold for battery pack265. If current voltage of battery pack265is not greater than the pre-determined permanent failure operating voltage threshold in step424, then BMU asserts a permanent failure indication in step440by setting a permanent failure (PF) flag in persistent memory that causes BMU266to permanently disable the battery pack265by blowing fuse212the next time that external power (e.g., AC adapter255) is provided to system200. Methodology400then ends in step442as shown.

However, if BMU266determines in step424that current charge level (voltage) of battery cells of battery pack265is greater than the pre-determined permanent failure operating voltage threshold for battery pack265, then methodology400proceeds to step426where EC280determines (e.g., by checking the AC adapter identifier) whether the connected external power source (e.g., AC adapter255) is capable of providing sufficient power to simultaneously run the system load320of system200while at the same time charging battery cells of battery pack265. If so, then BMU266allows battery charging to begin in step444, and any existing persistent BMU shutdown or persistent EC shutdown flags are cleared from persistent memory when current monitored charge level of battery pack365exceeds respective persistent BMU shutdown threshold and respective EC shutdown threshold during the charging operation.

After charging commences in step444, an optional system start-up delay may be implemented in step446during which charging of battery pack265continues while it is determined if sufficient battery charge level has met or exceeded the predetermined minimum acceptable operating voltage threshold value for startup of system200(i.e., startup of processor205and other power consuming components). If not, then system start up delay continues until current battery charge level reaches the predetermined minimum acceptable operating voltage threshold value and then proceeds as shown to step448where the persistent shutdown flag is cleared from persistent memory to allow EC280(e.g., using BIOS executing thereon) to again supply power to system load320(e.g., by closing D-FET312) and to allow system boot and OS operation to be initiated on processor205. Methodology400then terminates in step450as shown.

However, if in step426, EC280determines that the connected external power source is not capable of providing sufficient power to simultaneously run the system load320of system200while at the same time charging battery cells of battery pack265, then methodology400proceeds to step428where BMU266allows battery charging to begin.

During charging, it is determined in step430if the current monitored charge level of battery pack265meets or exceeds the persistent BMU shutdown threshold, and if so the persistent BMU shutdown flag is cleared from persistent memory in step432. Similarly, it is determined in step434if the current monitored charge level of battery pack265meets or exceeds the persistent EC shutdown threshold, and if so the persistent EC shutdown flag is cleared from persistent memory in step436. In step438, it is determined if the current monitored charge level of battery pack265meets or exceeds the persistent OS shutdown threshold. If not, then methodology400returns to step420as shown. However, if it is determined in step438that the current monitored charge level of battery pack265meets or exceeds the persistent OS shutdown threshold, then methodology400proceed to step448where the persistent shutdown flag is cleared from persistent memory to allow EC280(e.g., using BIOS executing thereon) to again supply power to system load320(e.g., by closing D-FET312) and to allow system boot and OS operation to be initiated on processor205. Methodology400then terminates in step450as shown.

It will be understood that the disclosed systems and methods may be implemented in one exemplary embodiment with an information handling system having multiple battery packs and corresponding respective multiple BMUs. In such an embodiment, a persistent shutdown management circuitry may be implemented by one or more system processing devices to individually disconnect discharged battery packs from the system load until external power is applied to recharge the respective disconnected discharged battery packs in combination or singularly until the disconnected battery packs are charged above the corresponding minimum acceptable operating voltage threshold, at which time the disconnected battery packs may be reconnected to the system load.

It will also be understood that one or more of the tasks, functions, or methodologies described herein (e.g., for BMU266, EC280, processor205or other suitable processing device) may be implemented, for example, as firmware or other computer program of instructions embodied in a non-transitory tangible computer readable medium that is executed by a CPU, controller, microcontroller, processor, microprocessor, FPGA, ASIC, or other suitable processing device. Further, although replaceable smart battery packs are described in relation to some of the embodiments herein, it will be understood that the disclosed systems and methods may be implemented with battery systems that are non-replaceable and/or with battery systems controlled by external processing device/s.