Battery backup circuit and techniques

Abstract

Various backup battery techniques are described that automatically take over and supply system voltage to electrical equipment associated with a workstation when all other voltage sources drop out. Using the techniques of this disclosure, a DC battery backup circuit, during independent and unsupervised operation allows a seamless transition to the voltage of the self-contained battery when the main (VSYS) source voltage begins to fail. The DC battery' backup circuit then transitions off and begins recharging its self-contained battery as normal host DC voltage returns.

Description

Attorney Docket No. 5983.516WO1BATTERY BACKUP CIRCUIT AND TECHNIQUESCLAIM OF PRIORITY

[0001] This application claims the benefit of priority to U.S. Provisional Application Serial No. 63 / 719,563 titled “BATTERY BACKUP CIRCUIT AND TECHNIQUES” to Ary Inthaluxay et al., filed November 12, 2024, which is incorporated by reference herein in its entirety.FIELD OF THE DISCLOSURE

[0002] This document pertains generally, but not by way of limitation, to power management systems including backup power systems.BACKGROUND

[0003] Power management systems play an important role in various electronic devices and equipment, particularly in applications where an uninterrupted power supply is desirable. In medical settings, such as hospitals and clinics, maintaining continuous power to essential equipment may be a matter of life and death. Traditional power backup systems often rely on uninterruptible power supplies (UPS) or standby generators, which may have limitations in terms of response time and seamless power transition.

[0004] The evolution of battery technology has led to the development of more sophisticated backup power solutions. These systems typically incorporate primary and secondary power sources to ensure continuous operation during power outages or when switching between power sources. As technology advances, there is a growing need for more efficient and reliable backup power systems that may meet the demands of critical applications.

[0005] In recent years, there has been a growing interest in developing more robust and responsive backup power systems. Engineers and researchers have been exploring ways to minimize transition times, reduce the risk of power interruptions, and create more reliable backup powerAttorney Docket No. 5983.516WO1solutions. This ongoing research and development in the field of power management continues to drive innovation and improvements in backup power technology.SUMMARY OF THE DISCLOSURE

[0006] This disclosure describes various backup battery techniques that automatically take over and supply system voltage to electrical equipment associated with a workstation when all other voltage sources drop out.Using the techniques of this disclosure, a DC battery backup circuit, during independent and unsupervised operation allows a seamless transition to the voltage of the self-contained battery when the main (VSYS) source voltage begins to fail. The DC batten' backup circuit then transitions off and begins recharging its self-contained battery as normal host DC voltage returns.

[0007] In some aspects, this disclosure is directed to a backup power circuit configured to couple with a backup battery, the backup power circuit comprising: a voltage comparator circuit configured to compare a system voltage to a backup battery voltage; a latching circuit coupled to an output of the voltage comparator circuit; and a switch circuit controlled by the latching circuit and configured to couple the backup battery to a system power bus when activated, wherein the voltage comparator circuit is configured to trigger the latching circuit when the system voltage drops below the backup battery voltage by a predetermined threshold.

[0008] In some aspects, this disclosure is directed to a power system comprising: a main power source configured to supply a system voltage; a backup battery; a bidirectional buck-boost converter coupled to a system power bus; and a backup power circuit configured to bypass the bidirectional buck-boost converter and couple the backup battery directly to the system power bus when the system voltage drops below a threshold, wherein the backup power circuit operates independently of software control.

[0009] In some aspects, this disclosure is directed to a power supply circuit coupled with an AC voltage source and a backup battery, wherein the backup battery has one or more battery cells, the power supply circuit comprising: an analog comparator circuit coupled with a system power bus and a backup battery node, the analog comparator circuit configured for: comparing aAttorney Docket No. 5983.516WO1system voltage at the system power bus and a voltage of the backup battery at the backup battery node; and generating, in response to the system voltage being less than the voltage of the backup battery, a comparator circuit output signal; an analog latching circuit configured for: receiving the comparator circuit output signal; and generating a latching circuit output signal; a gate driver circuit configured for: receiving the latching circuit output signal; and generating a gate driver output signal; and a transistor configured for: receiving the gate driver output signal; and changing state, in response to receiving the gate driver output signal, to couple the backup battery node with the system power bus to supply the voltage of the backup battery to an external load.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0011] FIG. 1 depicts an example of a workstation that may implement various techniques of this disclosure.

[0012] FIG. 2 is a block diagram of an example of an electrical system of the workstation of FIG. 1, where the AC voltage source is disconnected, the primary' backup battery is supplying operating power, and the secondary' backup battery is charging.

[0013] FIG. 3 is a schematic diagram of an example of a backup power circuit that may implement various techniques of this disclosure.

[0014] FIG. 4 is a block diagram of the electrical system of the workstation of FIG. 1 , where both the AC voltage source and the primary backup battery' are disconnected and the secondary' backup battery' is supplying operating power.

[0015] FIG. 5 is a block diagram of the electrical system of the workstation of FIG. 1, where the AC voltage source is supplying operating power and the primary backup battery' and the secondary backup battery are being charged.Attorney Docket No. 5983.516WO1

[0016] FIG. 6 is a block diagram of the electrical system of the workstation of FIG. 1, where the AC voltage source is supplying operating power, the primary main batten' is disconnected, and the secondary backup battery is being charged.

[0017] FIG. 7 is a block diagram of an example of an independent backup battery system for use with a workstation.

[0018] FIG. 8 depicts another example of a workstation that may implement various techniques of this disclosure.

[0019] FIG. 9 depicts another example of a workstation that may implement various techniques of this disclosure.

[0020] FIG. 10 depicts another example of a workstation that may implement various techniques of this disclosure.

[0021] FIG. 11 is a flow diagram of an example of a method for providing backup power using various techniques of this disclosure.DETAILED DESCRIPTION

[0022] Many workstations, such as tables, stationary carts, and mobile carts, include batten- management systems that maintain an uninterrupted power supply to electrical equipment associated with the workstation. Such battery management systems may be particularly important in hospitals, data centers, and financial institutions, for example.

[0023] Existing battery management systems typically incorporate primary and secondary power sources, along with control circuitry to manage the transition between them. However, these existing solutions rely heavily on digital control systems and software control to detect power loss and / or initiate backup power. The present inventors have recognized that the use of digital control systems and software control may introduce transients, which may be particularly undesirable in scenarios where rapid response times are essential. The present inventors have recognized a need for improved battery management systems.

[0024] This disclosure describes various backup battery techniques that automatically take over and supply system voltage to electrical equipmentAttorney Docket No. 5983.516WO1associated with a workstation when all other voltage sources drop out. Using the techniques of this disclosure, a DC battery backup circuit, during independent and unsupervised operation allows a seamless transition to the voltage of the self-contained battery when the main (VSYS) source voltage begins to fail. The DC battery' backup circuit then transitions off and begins recharging its self-contained battery as normal host DC voltage returns.

[0025] FIG. 1 depicts an example of a workstation that may implement various techniques of this disclosure. The workstation 100 is an example of a powered workstation, e.g., mobile cart, having a permanent / resident battery providing power to one or more electronic devices coupled to the workstation. The workstation 100 includes a permanently installed primary battery 102, e.g., a resident battery, to supply power to the electronic equipment and / or components of the cart. The workstation 100 further includes a backup battery 104 to supply power when the charge in the primary battery 102 has been sufficiently depleted, such as below a threshold. The workstation 100 includes a removable battery' 106 that may supply power when the charge in both the primary battery' 102 and the backup battery 104 has been sufficiently depleted.

[0026] A removable battery refers to a battery that is designed to be easily detached and reattached to the workstation, e.g., mobile cart. This ty pe of battery is intended for quick and convenient removal for recharging purposes, allowing users to swap out depleted batteries with fully charged ones without significant downtime. The removable battery typically features user-friendly mechanisms such as latches or connectors that facilitate its easy removal and replacement, ensuring minimal disruption to the operation of the workstation.

[0027] The workstation 100 includes an electrical system 110. The electrical system 110 is configured for supplying power to various user peripherals, including computers, monitors, locking mechanisms, and the like.

[0028] The workstation 100 is an example of a powered workstation due to the inclusion of its permanently installed primary battery 102, e.g., resident battery. The powered workstation needs to be plugged into an AC voltageAttorney Docket No. 5983.516WO1source 108, e.g., mains power, to charge the primary battery 102. When the primary battery’ 102 is fully charged, a powered workstation does not need to be plugged into the AC voltage source 108.

[0029] Described below are other examples of powered workstations and unpowered workstations. The techniques of this disclosure are applicable to both powered and unpowered workstations.

[0030] FIG. 2 is a block diagram of an example of the electrical system 110 of the workstation of FIG. 1, where the AC voltage source is disconnected, the primary' backup battery is supplying operating poyver, and the secondary backup battery is charging. The electrical system 110 is configured for coupling with an AC voltage source 202, such as mains poyver. The electrical system 110 is further configured for coupling with a backup battery, such as the mam battery 204, e.g.. the primary battery or the main battery having one or more battery cells, or backup battery 206, e g., a secondary battery' having one or more battery' cells, during a loss of AC power.

[0031] The electrical system 110 includes an AC-DC poyver supply circuit 208 configured for coupling yvith an AC voltage source 202 and generating, via the AC voltage source 108, a system voltage VSYS. e.g., 14.75 VDC. The system voltage VSYS is supplied via a short circuit protection circuit 212 to a DC-AC inverter supply circuit 214. The DC- AC inverter supply circuit 214 supplies AC poyver via a syvitch output 216 to one or more user peripherals 218.

[0032] The electrical system 110 further includes a bidirectional DC-DC converter circuit 210, e.g., a buck-boost converter. As described in more detail below, the bidirectional DC-DC converter circuit 210 is coupled between the main battery 204 and system power bus 220 and configured for generating the system voltage VSYS in the absence of sufficient AC power from the AC voltage source 202. In addition, the bidirectional DC-DC converter circuit 210 is configured for charging the main battery’ 204 when AC voltage source 202 is present.

[0033] In FIG. 2, the AC voltage source 202 is disconnected, the user peripherals 218 are poyvered from the main battery’ 204, e.g., the primary’Attorney Docket No. 5983.516WO1battery, via the bidirectional DC-DC converter circuit 210, and the backup battery 206, e.g.. the secondary battery, is charging.

[0034] FIG. 3 is a schematic diagram of an example of a backup power circuit 300 that may implement various techniques of this disclosure. The backup power circuit 300 is configured for coupling with a backup battery, such as the main battery 204 or the backup batten’ 206 of FIG. 2. The backup power circuit 300 includes various sections such as a turn on section 302, a turn off section 304, and a latch section 306.

[0035] The turn on section 302 includes a voltage comparator circuit 308 configured to compare a system voltage VSYS to a backup battery voltage PACK+ of a backup battery. The voltage comparator circuit 308 includes an analog comparator circuit 310. The latch section 306 includes an analog comparator circuit coupled to an output 314 of the voltage comparator circuit 308.

[0036] The backup power circuit 300 includes a switch circuit 316. such as including two transistors QI and Q2. controlled by the latching circuit 312 and configured to couple the backup battery, such as the main battery 204 or the backup battery 206 of FIG. 2, to a system power bus 220 when activated. The voltage comparator circuit 308 is configured for triggering the latching circuit 312 when the system voltage VSYS drops below the backup battery voltage PACK+ by a predetermined threshold, such as 0.5V. When the system voltage VSYS drops below the backup battery voltage PACK+ by the predetermined threshold, the following sequence occurs in the backup power circuit 300.

[0037] The analog comparator circuit 310 compares the system voltage VSYS at the system pow er bus 220 and a voltage of the backup batten,' at the backup battery node 322. If the analog comparator circuit 310 detects that the voltage VSYS has fallen below the voltage PACK.+ by a predetermined threshold, the voltage comparator circuit 308 then generates an output signal at its output 314. This output signal is applied to the latching circuit 312 in the latch section 306. Upon receiving the signal from the voltage comparator circuit 308, the latching circuit 312 generates a latching circuit output signal 324. The latching circuit output signal 324 is applied to a gateAttorney Docket No. 5983.516WO1driver circuit 318, which receives the latching circuit output signal 324 and generates a gate driver output signal 320.

[0038] The gate driver output signal 320 is then applied to the switch circuit 316, such as the gate terminals of transistors QI and Q2 of the switch circuit 316. The transistors QI and Q2 change state, e.g.. turn ON, in response to the gate driver output signal 320, activating and coupling the backup battery voltage node PACK+ 322 (such as from the main battery 204 or the backup battery 206 of FIG. 2) to the system power bus 220. This connection allows the backup battery to supply its voltage to the system power bus 220 and to an external load, such as the user peripherals 218 of FIG. 2. In this manner, the backup power circuit 300 maintains a system voltage VSYS at a backup battery' voltage level until the buck-boost bidirectional DC-DC converter circuit 210 of FIG. 2, e.g., the buck-boost converter, resumes normal operation.

[0039] The analog comparator circuit 310, the analog latching circuit 312, the gate driver circuit 318, and transistors QI and Q2 operate independent of software control. The entire process occurs rapidly through the analog circuitry of the backup power circuit 300 and is independent of software control, ensuring a seamless transition to backup power without introducing transients or relying on software control. The backup power circuit 300 operates independently of software control, meaning it does not rely on any programmed instructions, digital signals, or software-based decision-making processes to perform its core power switching functionality7. The analog components of the backup power circuit 300, including the voltage comparator circuit 308, the latching circuit 312, and the gate driver circuit 318, work together to detect voltage drops, make switching decisions, and activate the backup power source without any intervention from a microprocessor or software algorithm. This software-independent operation ensures rapid response times and eliminates potential delays or failures that could occur in software-controlled systems, thereby providing a more reliable and instantaneous transition to backup power when needed.

[0040] As mentioned above, the backup power circuit 300 further includes the turn off section 304. The turn off section 304 includes a current senseAttorney Docket No. 5983.516WO1circuit 326 configured to detect a direction of current 328 flowing between the backup battery, such as the main battery 204 or the backup battery 206 of FIG. 2, and the system power bus 220. The current sense circuit 326 is configured to deactivate the latching circuit 312 when the current sense circuit 326 detects from the direction of current 328 that current is flowing from the system power bus 220 to the backup battery. More particularly, the current sense circuit 326 includes a current sense resistor R1 and an analog comparator circuit 330 having inputs coupled with the two terminals of the current sense resistor Rl. The comparator analog comparator circuit 330 detects the direction of current 328 based on the polarity of the voltage drop across the current sense resistor Rl. When the current reverses direction, the voltage polarities on the comparator’s inputs reverse, causing the analog comparator circuit 330 to generate an output signal 332, thereby detecting the change in the direction of current flow.

[0041] The analog comparator circuit 330 determines that the system voltage VSYS is greater than the voltage of the backup battery, shown as the backup battery voltage PACK+ 322, when the direction of current 328 is flowing from VSYS to PACK+ (right to left in FIG. 3). When the analog comparator circuit 330 determines that the system voltage VSYS is greater than the voltage of the backup battery at the backup battery node, the analog comparator circuit 330 generates an output signal 332.

[0042] As seen in FIG. 3, the analog comparator circuit 330 is coupled with the latching circuit 312 via an analog comparator circuit 334. The analog latching circuit 312 is configured for receiving the comparator circuit output signal 332 generating a latching circuit output signal 336. The gate driver circuit 318 is configured for receiving the second latching circuit output signal 336 and generating another gate driver output signal 320 to turn OFF the transistors of the switch circuit 316. The gate terminals of the transistors QI and Q2 of the switch circuit 316 are configured for receiving the gate driver output signal 320 and changing state, e.g., turn OFF. to decouple the backup battery node PACK+ from the system power bus 220.

[0043] The backup power circuit 300 of FIG. 3 operates the same regardless of which backup battery of FIG. 2 is used. In the particularAttorney Docket No. 5983.516WO1example shown in FIG. 2, the primary' main battery 204 is supplying operating power while the secondary backup battery 206 is charging.However, as described below with respect to FIG. 4, both the AC voltage source and the primary' main battery 204 are disconnected and the secondary backup battery 206 is supplying operating power.

[0044] FIG. 4 is a block diagram of the electrical system 110 of the workstation of FIG. 1, where both the AC voltage source and the primary main battery' 204 are disconnected and the secondary' backup battery 206 is supplying operating power. Many of the components of FIG. 4 are the same as the components of FIG. 2 and. for conciseness, will not be described in detail again.

[0045] The electrical system 110 is an example of a power system having a main power source configured to supply a system voltage. In some examples, the main power source is the AC voltage source 202 and, in other examples, the main power source is the primary' main battery' 204. In addition, the power system further includes a backup battery, such as the secondary’ backup battery 206. As described above, the electrical system 110 includes the bidirectional DC-DC converter circuit 210, such as a buckboost converter, coupled to the system power bus 220.

[0046] In the configuration shown in FIG. 2, the primary main battery 204 is connected and supplies via the bidirectional DC-DC converter circuit 210 the system voltage VSYS to the system power bus 220. However, in the configuration shown in FIG. 4, both the AC voltage source 202 and the primary main battery’ 204 are disconnected and, using the backup power circuit 300 of FIG. 3, the secondary backup battery 206 is supplying the system voltage VSYS to the system power bus 220.

[0047] As seen in FIG. 4, unlike the primary main battery 204, the secondary' backup battery 206 does not use the buck-boost converter. Using the voltage comparator circuit 308 of FIG. 3, the backup power circuit 300 of FIG. 3 is configured to bypass the buck-boost converter and couple the secondary backup battery 206 directly to the system power bus 220 when the system voltage drops below a threshold. The backup power circuit 300 is configured to maintain the system voltage VSYS at a backup battery' voltageAttorney Docket No. 5983.516WO1level, e.g., the voltage of the secondary backup battery' 206, until the buckboost converter 210 resumes normal operation.

[0048] When the primary' main battery' 204 is reconnected, such as shown in FIG. 2. the buck-boost converter 210 resumes normal operation.

[0049] FIG. 5 is a block diagram of the electrical system 110 of the workstation of FIG. 1, where the AC voltage source is supplying operating power and the primary main battery' 204 and the secondary backup battery 206 are being charged. Many of the components of FIG. 4 are the same as the components of FIG. 2 and, for conciseness, will not be described in detail again.

[0050] The electrical system 110 of FIG. 5 is in a normal operation mode following the current sense circuit 326 of FIG. 3 deactivating the latching circuit 312 of FIG. 3. During normal operation, the AC voltage source 202 generates, via the AC-DC power supply circuit 208, the system voltage VSYS, e.g., 14.75VDC, on the system power bus 220, which supplies the user peripherals 218.

[0051] In the normal operation mode and in response to the current sense circuit deactivating the latching circuit, the system voltage VSYS directly charges the secondary backup battery 206. and the primary main battery 204 is charged via the bidirectional DC-DC converter circuit 210. More particularly, the bidirectional DC-DC converter circuit 210 generates a DC voltage VBAT that is supplied to the main battery 204 for charging.

[0052] FIG. 6 is a block diagram of the electrical system 110 of the workstation of FIG. 1, where the AC voltage source is supplying operating power, the primary main battery' 204 is disconnected, and the secondary backup battery 206 is being charged. While the main battery 204 is disconnected from the electrical system 110, the AC voltage source 202 generates, via the AC-DC power supply circuit 208, the system voltage VSYS, e.g., 14.75VDC, on the system power bus 220, which supplies the user peripherals 218.

[0053] The system voltage VSYS directly charges the secondary backup battery 206. The bidirectional DC-DC converter circuit 210 generates a DC voltage VBAT that is supplied to a terminal 600.Attorney Docket No. 5983.516WO1

[0054] FIG. 7 is a block diagram of an example of an independent backup batery system 700 for use with the workstation 100. As seen in FIG. 7. the backup battery system 700 includes the backup power circuit 300 of FIG. 3 and a separate buck-boost DC-DC converter circuit 210 of FIG. 2, configured for battery charging.

[0055] The backup battery system 700 is coupled with a backup battery 702, such as one or both of the primary main battery 204 and the secondary backup battery 206 of FIG. 2. The backup battery 702 is the backup power source that provides voltage to the system power bus 220 when the primary power source, e.g.. the AC voltage source 202 of FIG. 2, is insufficient.

[0056] The backup battery 702 is coupled with a battery management circuit 704 that continuously monitors the battery cell parameters and currents. The switch circuit 300 ensures that the system voltage VSYS remains within the acceptable range for the load, e g., the user peripherals 218 of FIG. 2. When the system voltage VSYS falls below the voltage of the backup battery 702, the switch circuit 300 connects Pack+ to VSYS and disengages the buck-boost batten’ charger circuit, ensuring that the load continues to receive power.

[0057] The control circuit 706 monitors the system power bus 220 and is in communication with the battery management circuit 704 and the DC-DC converter circuit 210 via an I2C communication 708 (Inter-Integrated Circuit).

[0058] FIG. 8 depicts another example of a workstation that may implement various techniques of this disclosure. The workstation 800 is another example of a powered workstation, e.g., mobile cart, having a permanent / resident battery providing power to one or more electronic devices coupled to the workstation. The workstation 800 includes a permanently installed primary batten' 102, e.g., a resident battery, to supply power to the electronic equipment and / or components of the cart. The workstation 800 further includes a backup battery’ 104 to supply power when the charge in the primary battery 102 has been sufficiently depleted, such as below a threshold. The workstation 800 does not include a removable battery, such as the removable battery 106 of FIG. 1.Attorney Docket No. 5983.516WO1

[0059] The workstation 800 includes an electrical system 110. The electrical system 110 is configured for supplying power to various user peripherals, including computers, monitors, locking mechanisms, and the like.

[0060] The workstation 800 is an example of a powered workstation due to the inclusion of its permanently installed primary battery 102, e.g., resident battery. The powered workstation needs to be plugged into an AC voltage source 108, e.g., mains power, to charge the primary battery 102. When the primary battery’ 102 is fully charged, a powered workstation does not need to be plugged into the AC voltage source 108. The techniques described above are applicable to the workstation 800.

[0061] FIG. 9 depicts another example of a workstation that may implement various techniques of this disclosure. The w orkstation 900 is an example of anon-powered workstation, e.g., mobile cart, having a removable battery providing power to one or more electronic devices coupled to the workstation. The workstation 900 includes a backup battery 902 and a removable battery’ 904. The backup battery 902 may supply power when the charge in the removable battery' 904 has been sufficiently depleted, such as below a threshold. Non-pow ered mobile carts do not include a resident battery' and need to be plugged into an AC voltage source, e.g., mains power, to provide power to a computer, for example, associated with the workstation 900.

[0062] FIG. 10 depicts another example of a workstation that may implement various techniques of this disclosure. The workstation 1000 is an example of anon-powered workstation, e.g., mobile cart, connected to a power supply providing power to one or more electronic device coupled to the workstation. The workstation 1000 includes a backup battery’ 1002 and a power strip 1004. The power strip 1004 may be plugged into an AC voltage source, e.g., mains power, via an extension cord 1006 to provide power to the components of the workstation 1000. The backup battery' 1002 may supply power to the components when the AC voltage source is not present.

[0063] FIG. 11 is a flow diagram of an example of a method 1100 for providing backup pow'er using various techniques of this disclosure.Attorney Docket No. 5983.516WO1

[0064] At block 1102, the method 1100 includes monitoring a system voltage and a backup battery voltage. For example, the voltage comparator circuit 308 of the backup power circuit 300 of FIG. 3 monitors the system voltage VSYS and the backup battery voltage PACK+.

[0065] At block 1104, the method 1100 includes activating, independent of software control, a switch to couple the backup battery to a system power bus when the system voltage drops below the backup battery voltage. For example, the latching circuit 312 activates the switch circuit 316, each of FIG. 3, when the system voltage VSYS drops below the backup battery voltage.

[0066] At block 1106, the method 1100 includes monitoring a current flow direction between a backup battery and the system power bus in hardware irrespective of software control. For example, the current sense circuit 326 monitors a direction of current 328 between a backup battery and the system power bus 220.

[0067] At block 1108, the method 1100 includes deactivating, independent of software control, the switch when current flow is detected from the system power bus to the backup battery. For example, the latching circuit 312 deactivates the switch circuit 316, each of FIG. 3, when current flow is detected from the system power bus 220 to the backup battery.Various Notes

[0068] Each of the non-limiting claims or examples described herein may stand on its own, or may be combined in various permutations or combinations w ith one or more of the other examples.

[0069] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The draw ings show, by w ay of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as ‘"examples.” Such examples may include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one orAttorney Docket No. 5983.516WO1more claims thereof), either with respect to a particular example (or one or more claims thereof), or with respect to other examples (or one or more claims thereof) shown or described herein.

[0070] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.

[0071] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0072] Method examples described herein may be machine or computer-implemented at least in part. Some examples may include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods may include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code may include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code may be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact discs and digital video discs), magnetic cassettes, memory cards or sticks.Attorney Docket No. 5983.516WO1random access memories (RAMs), read only memories (ROMs), and the like.

[0073] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more claims thereof) may be used in combination with each other. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments may be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

Attorney Docket No. 5983.516WO1CLAIMSWhat is claimed is:

1. A backup power circuit configured to couple with a backup battery, the backup power circuit comprising:a voltage comparator circuit configured to compare a system voltage to a backup battery voltage;a latching circuit coupled to an output of the voltage comparator circuit; anda switch circuit controlled by the latching circuit and configured to couple the backup battery to a system power bus when activated, wherein the voltage comparator circuit is configured to trigger the latching circuit when the system voltage drops below the backup battery voltage by a predetermined threshold.

2. The backup power circuit of claim 1, comprising:a current sense circuit configured to detect a direction of current flowing between the backup battery’ and the system power bus.wherein the current sense circuit is configured to deactivate the latching circuit when the current sense circuit detects current flowing from the system power bus to the backup battery'.

3. The backup power circuit of claim 2, comprising:a bidirectional DC-DC converter circuit configured to:charge, in response to the current sense circuit deactivating the latching circuit, the backup battery.

4. The backup power circuit of claim 1, comprising:an AC-DC power supply circuit configured for:coupling with an AC voltage source; andgenerating, via the AC voltage source, the system voltage.

5. The backup power circuit of claim 1, wherein the voltage comparator circuit, the latching circuit, and the switch circuit are configured to operate independently of software control.Attorney Docket No. 5983.516WO16. The backup power circuit of claim 1, comprising:a bidirectional DC-DC converter circuit configured for:coupling with a primary battery having one or more battery cells; andgenerating, via the primary battery', the system voltage.

7. The backup power circuit of claim 1, in combination with a workstation, wherein the backup battery is a permanent battery configured to provide power to one or more electronic components of the workstation.

8. The backup power circuit of claim 1, in combination with a workstation, wherein the backup battery is a removable backup battery configured to provide power to one or more electronic components of the workstation.

9. The backup power circuit of claim 1, in combination with a workstation, wherein the workstation does not include a removable backup battery.

10. A power system comprising:a main power source configured to supply a system voltage;a backup battery;a bidirectional buck-boost converter coupled to a system power bus; anda backup power circuit configured to bypass the bidirectional buckboost converter and couple the backup battery directly to the system power bus when the system voltage drops below a threshold,wherein the backup power circuit operates independently of software control.

11. The power system of claim 10, wherein the backup power circuit is configured to maintain system voltage at a backup battery voltage level until the buck-boost converter resumes normal operation.

12. The power system of claim 10, wherein the main power source is an AC voltage source.

13. The power system of claim 10, wherein the mam power source is a primary battery.Attorney Docket No. 5983.516WO114. A power supply circuit coupled with an AC voltage source and a backup battery, wherein the backup battery’ has one or more battery cells, the power supply circuit comprising:an analog comparator circuit coupled with a system power bus and a backup battery node, the analog comparator circuit configured for:comparing a system voltage at the system power bus and a voltage of the backup battery at the backup battery' node; and generating, in response to the system voltage being less than the voltage of the backup battery, a comparator circuit output signal; an analog latching circuit configured for:receiving the comparator circuit output signal; and generating a latching circuit output signal;a gate driver circuit configured for:receiving the latching circuit output signal; and generating a gate driver output signal; anda transistor configured for:receiving the gate driver output signal; andchanging state, in response to receiving the gate driver output signal, to couple the backup battery node with the system power bus to supply the voltage of the backup battery to an external load.

15. The pow er supply circuit of claim 14, comprising:an AC-DC power supply circuit configured for:coupling with the AC voltage source; andgenerating the system voltage.Attorney Docket No. 5983.516WO116. The power supply circuit of claim 14, comprising:a bidirectional DC-DC converter circuit configured for:coupling with a primary battery having one or more battery cells; andgenerating the system voltage.

17. The power supply circuit of claim 14, wherein the analog comparator circuit is a first analog comparator circuit, wherein the comparator circuit output signal is a first comparator circuit output signal, wherein the latching circuit output signal is a first latching circuit output signal, and wherein the gate driver output signal is a first gate driver output signal, the power supply circuit comprising:a second analog comparator circuit configured for:determining that the system voltage is greater than the voltage of the backup battery at the backup battery node; and generating a second comparator circuit output signal; wherein the analog latching circuit is configured for:receiving the second comparator circuit output signal; and generating a second latching circuit output signal; wherein the gate driver circuit is configured for:receiving the second latching circuit output signal; and generating a second gate driver output signal; and wherein the transistor is configured for:receiving the second gate driver output signal; and changing state, in response to receiving the second gate driver output signal, to decouple the backup battery' node from the system power bus.

18. The power supply circuit of claim 14, wherein the analog comparator circuit, analog latching circuit, gate driver circuit, and transistor are configured for operating independently of software control.Attorney Docket No. 5983.516WO119. The power supply circuit of claim 17, comprising:a bidirectional DC-DC converter circuit configured for:charging, in response to receiving the second latching circuit output signal, the backup battery.

20. A method for providing backup power, the method comprising:monitoring a system voltage and a backup battery voltage; activating, independent of software control, a switch to couple the backup battery7to a system power bus when the system voltage drops below the backup battery voltage;monitoring a current flow direction between a backup battery and the system power bus; anddeactivating, independently of software control, the switch when current flow is detected from the system power bus to the backup batten,'.

21. The method of claim 20, comprising:disabling a battery charger circuit when the switch is activated to connect the backup batten,' to the system power bus; andre-enabling the battery charger circuit when the switch is deactivated.

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