Battery under-voltage locking and reversed polarity charger protection circuit

Abstract

The invention discloses a battery protection circuit for preventing overdischarge of a battery and a reverse polarity battery charger protection circuit. The battery protection circuit includes a battery input configured to receive a battery voltage; a reference voltage input configured to receive a low battery reference voltage; a comparator for comparing a first signal indicative of the battery voltage with a second signal indicative of the reference voltage and generating an output indicative of a low battery voltage; a feedback resistor that couples an output of the comparator to the reference voltage input to generate a hysteresis; and a battery disconnection circuit for disconnecting a battery voltage applied to the load. The reverse polarity battery charger protection circuit has a relay and a diode for detecting a reverse polarity connection of the charger to the battery.

Description

Technical Field

[0001] This disclosure generally relates to circuit protection for batteries and charging systems, and more specifically to protection against over-discharge of batteries and reverse polarity protection for battery chargers. Background Technology

[0002] Batteries, such as lead-acid batteries, are commonly used to power electrical loads. A battery can consist of one or more battery cells designed to operate within a specific voltage range. Efficient power dissipation circuitry may be required to prevent over-discharge and to provide reverse polarity protection for the battery charger. Summary of the Invention

[0003] According to one aspect of this disclosure, a battery protection circuit includes: a battery input configured to receive a battery voltage; a reference voltage input configured to receive a low battery reference voltage; a comparator configured to compare a first signal indicating the battery voltage with a second signal indicating the reference voltage and generate an output indicating a low battery voltage; a feedback resistor coupling the output of the comparator to the reference voltage input to generate hysteresis; and a battery disconnect circuit configured to disconnect the battery voltage applied to a load.

[0004] According to another aspect of this disclosure, a battery system includes: a battery having one or more battery cells and generating a battery voltage; an electrical load configured to receive the battery voltage for supplying power to the electrical load; and a battery protection circuit. The battery protection circuit includes: a battery input configured to receive the battery voltage; a reference voltage input configured to receive a low battery reference voltage; a comparator configured to compare a first signal indicating the battery voltage with a second signal indicating the reference voltage and generate an output indicating a low battery voltage; a feedback resistor coupling the output of the comparator to the reference voltage input to generate hysteresis; and a battery disconnect circuit configured to disconnect the battery voltage applied to the load.

[0005] According to another aspect of this disclosure, a reverse polarity battery charger protection circuit comprises: a battery charger input terminal configured to receive a power supply voltage; a battery connector configured to couple with a first polarity output terminal and a second polarity output terminal of a battery; a battery charger input terminal configured to receive a charging voltage from a battery charger; a relay coupled in series with the battery charger input terminal; a diode coupled in parallel with the battery charger; and a transistor coupled with the relay and the diode. The diode and the relay allow charging of the battery with the battery charger and prevent charging of the battery with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

[0006] According to another aspect of this disclosure, a battery charging system includes: a battery having one or more battery cells and generating a battery voltage; a battery charger generating a charging voltage to charge the battery; and a reverse polarity battery charging protection circuit coupling the battery charger to the battery. The reverse polarity battery charging protection circuit includes: a battery charger input configured to receive a power supply voltage; a battery connector configured to couple to a first polarity output and a second polarity output of the battery; a battery charger input configured to receive a charging voltage from the battery charger; a relay coupled in series with the battery charger input; a diode coupled in parallel with the battery charger; and a transistor coupled to the relay and the diode, wherein the diode and the relay allow charging of the battery with the battery charger and prevent charging of the battery with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

[0007] Those skilled in the art will further understand and appreciate these and other features, advantages and objectives of this disclosure by referring to the following description, claims and drawings. Attached Figure Description

[0008] In the attached diagram:

[0009] Figure 1 It is a side perspective view of a patient support device equipped with a battery and charging system in an example medical facility;

[0010] Figure 2 This is a block diagram of a battery and charging system having an undervoltage battery protection circuit and a reverse polarity battery charger protection circuit according to the present disclosure.

[0011] Figure 3 This is a circuit diagram illustrating an undervoltage battery protection circuit according to one aspect of this disclosure; and

[0012] Figure 4 This is a circuit diagram illustrating a reverse polarity battery charger protection circuit according to another aspect of this disclosure. Detailed Implementation

[0013] The embodiments shown here primarily relate to combinations of method steps, systems, devices, and apparatus components, which are associated with systems, methods, and procedures for visually reproducing patient-related medical events in a medical setting. Therefore, in the accompanying drawings, apparatus components and method steps have been indicated with conventional symbols where appropriate, and only specific details relevant to understanding embodiments of this disclosure are shown so as not to obscure this disclosure with details readily understood by one of ordinary skill in the art who will benefit from the description herein. Furthermore, the same numerals in the specification and drawings denote the same elements.

[0014] The specific structures and processes shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the inventive concept as defined in the appended claims. Therefore, unless expressly stated otherwise in the claims, the specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting.

[0015] The terms “comprising,” “including,” “containing,” or any other variation thereof are intended to cover non-exclusive inclusion, meaning that a process, method, article of manufacture, or apparatus that comprises a list of elements does not contain only those elements, but may also contain other elements not expressly listed or inherent to such process, method, article of manufacture, or apparatus. Unless otherwise specified, an element beginning with “comprising…” does not exclude the presence of additional identical elements in the process, method, article of manufacture, or apparatus that includes that element.

[0016] Reference Figures 1 to 4 Reference numeral 10 generally denotes a battery and charging system, which in one example is embodied in a patient support device 12 used in a medical facility 14. The battery and charging system 10 has a battery 16 configured to store electrical energy and supply backup power that can be used as a primary power supply. The battery and charging system 10 includes an undervoltage battery protection circuit for cutting off the power supply from the battery 16 to electrical loads in the event of over-discharge resulting in low or undervoltage. The battery and charging system 10 also includes a battery charger 18 configured to charge the battery 16. The battery and charging system 10 also includes a reverse polarity battery charger protection circuit for protecting the battery charger 18 in the event of reverse polarity connection between the battery terminals and the charging circuitry, thereby reducing leakage current through the battery and charger circuitry network.

[0017] Reference Figure 1In one example, patient support device 12 is shown as a transport stretcher located within a medical facility 14. It is conceivable that patient support device 12 may be configured as other types of stretchers, medical beds, other types of beds, mattresses, examination tables, operating tables, recliners, or any other suitable structures for supporting the patient and powered devices (also referred to as electrical loads) and having batteries and charging systems, without departing from the teachings herein. Furthermore, the medical facility 14 shown in this example may be located in any suitable location for providing treatment to the patient on patient support device 12.

[0018] In one example, the patient support device 12 is shown with its upper frame 22 supported on a base frame 20. The upper frame 22 is typically adjustable relative to the base frame 20, for example, to adjust height, tilt, etc. The upper frame 22 includes a support surface for supporting a mattress 24. Different portions of the mattress 24 can be adjusted relative to the upper frame 22. For example, portions of the mattress 24 located at the head end 26 or foot end 28 can extend upwards at an angle relative to the support surface of the upper frame 22.

[0019] The patient support device 12 is shown to have various features for transporting and treating patients. For example, the patient support device 12 includes a handle 32 located on the side rail assembly 30 and at the head end 26 and foot end 28 for transporting the patient support device 12 to different locations within the medical facility 14 and other locations.

[0020] The patient support device 12 may include various motors that can be mounted on and powered by electricity, thereby defining electrical loads 34. For example, the patient support device 12 may include various motors (such as electric motors) that can be used to drive and reconfigure the mattress 24, such as tilting or lowering a portion of the mattress 24, and raising or lowering the mattress 24. According to other examples, electronic devices may be powered by a plug-in main power supply or battery 16, such as user input and output devices in the form of touchscreen displays and switches. Furthermore, electronic devices in the form of user interfaces, such as tablets, laptops, and smartphones, may be powered on the patient support device 12 and connected to a power source via electrical connections (e.g., through power plugs, USB / A, USB / B, and USB / C connectors). It should be understood that any one of the multiple electrical loads 34 can be connected to the patient support device 12 and powered by a main power supply or battery 16.

[0021] The base frame 20 is also shown supported by wheels 36 that contact the subfloor surface of the medical facility 14. The wheels 36 are typically connected to the base frame 20 via axles. The wheels 36 may be in the form of casters configured to rotate in an electrically driven mode via one or more electric motors as an additional electrical load powered by the main power supply or battery 16, thereby propelling the patient support equipment 12 for transport by caregivers, medical personnel, or other users.

[0022] Still referencing Figure 1 The patient support device 12 is shown with a power cord having a power plug 38 configured to connect to a main alternating current (AC) power supply 39 in the wall or floor of a medical facility 14. Thus, the main AC power supplied by the power distribution network in the medical facility 14 can be distributed and used to power various electrical loads 34 on the patient support device 12. The AC main power can be converted to direct current (DC) power by an AC-DC converter to supply a DC voltage, such as approximately 28 volts. Battery 16 is a rechargeable battery that can be used to power electrical loads when the AC power plug 38 is disconnected from the AC main power supply 39 (e.g., during transport of the patient support device 12 or if the AC main power supply 39 is unavailable). Battery charger 18 is configured to charge the rechargeable battery 16 using power supplied from the AC power supply 39 and received via the power plug 38, which is converted from AC power to DC power and used to charge the rechargeable battery 16.

[0023] See Figure 2 The battery and charging system 10 is shown coupled to a main AC power supply 39, which may include a power distribution network provided within the medical facility 14 to supply main AC power. According to one example, the main AC power may be supplied at 120 volts AC, or it may be supplied at 240 volts AC or other acceptable voltage levels. The main AC power is supplied to the patient support device 12 via a power cord and plug 38. The main AC power may be converted to DC voltage, such as approximately 28 volts DC. It is understood that it is conceivable that the medical facility 14 may also supply a 28-volt DC main power supply, which may be converted via an AC-DC converter circuit provided within the medical facility 14.

[0024] The converted DC main power supplied by AC-DC converter 40 is used as the main power supply V. ps The main power supply V ps Used to power electrical loads and charge rechargeable battery 16. Main power supply V ps It is provided as an input to the electric steering controller 42. Additionally, the main power V...ps It also supplies power to the battery charger 18. The electric steering controller 42 also receives battery power V supplied by the battery 16. bat The electric steering controller 42 includes an electric control circuit 60 that controls the power supply (i.e., main power V) for supplying power to one or more electrical loads 34. ps or battery power V bat When AC power plug 38 supplies main power V. ps At this time, one or more electrical loads 34 are powered by power received from the AC-DC converter 40 and converted from the AC power supply. If the battery and charging system 10 is not connected to the AC main power supply 39, or the AC main power supply V ps If unavailable (e.g., when patient support equipment 12 is being transported or placed in a location inaccessible to AC power supply 39), DC battery power V is supplied to one or more electrical loads 34 using battery 16. bat At this point, the power steering controller 42 determines which power source to supply to one or more electrical loads 34.

[0025] A DC voltage supplied by the AC mains power supply and converted by the AC-DC converter 40 is also supplied to the battery charger 18, which in turn is used to charge the rechargeable battery 16. According to one example, 120 volts of AC mains power, converted to approximately 28 volts DC by the AC-DC converter 40, is used to charge the rechargeable battery 16 to a full charge voltage of approximately 28 volts DC. The battery charger 18 may include a known battery charging circuit 54.

[0026] According to one example, battery 16 is a rechargeable battery, which can be configured as a lead-acid battery. Lead-acid battery 16 may include multiple series-coupled electrochemical cell units, the number of which is sufficient to produce the desired battery output voltage. For example, the lead-acid battery may include 14 cell units, each of which outputs approximately 2.1 volts when fully charged, for a total battery output voltage of approximately 28 volts. According to another example, 12 cell units may be series-coupled to produce a 24-volt output system. It should be understood that, upon detecting a sufficiently low voltage, undervoltage battery protection circuit 100 can advantageously cut off power supply to electrical load 34 to prevent the output voltage of each cell from dropping below 1.75 volts, thereby preventing damage to the cell units and the battery.

[0027] The electric steering controller 42 is also shown to have an undervoltage battery protection circuit 100. The undervoltage battery protection circuit 100 detects the battery output voltage V. batThe low voltage level of the battery 16 is prevented, and the power supply from the battery 16 to the electrical load 34 is cut off to prevent one or more electrical loads 34 from drawing power from the battery 16 when the battery voltage is low, thereby preventing the battery 16 from being over-consumed. The undervoltage battery protection circuit 100 advantageously employs hysteresis to prevent the electrical loads 34 from repeatedly reapplying to the battery 16 in an undervoltage state, and in particular, to prevent the electrical loads 34 from repeatedly reapplying to the battery 16 when the voltage of the battery cell (and therefore the voltage of the battery 16) has slightly increased and stabilized at the open-circuit voltage. For example, when the battery 16, which normally supplies about 28 volts DC, drops to about 21 volts DC, the undervoltage battery protection circuit 100 advantageously lowers the battery voltage V. bat The electrical load 34 is disconnected and prevented from reconnecting to the battery 16 until the battery 16 reaches a sufficiently high voltage (e.g., approximately 24 volts DC). This prevents the electrical load 34 from periodically and fully draining the battery 16 in an undervoltage state, which would lead to battery damage or performance degradation. It should be understood that the undervoltage battery protection circuit 100 can be integrated on a circuit board with the power control circuit 60 associated with the power steering controller, or it can be disconnected from the power control circuit 60.

[0028] Battery charger 18 is shown with a reverse polarity battery charger protection circuit 200. The reverse polarity battery charger protection circuit 200 detects the reverse polarity electrical connection between the positive (+) and negative (-) terminals of battery 16 and battery charger 18, so as to protect battery charger 18 in the event of a reverse polarity connection, thereby eliminating back-feeding to the charging circuit and reducing battery current leakage through the charger network. It should be understood that the reverse polarity battery charger protection circuit 200 may be integrated on a circuit board with the battery charging circuit 54 associated with battery charger 18, or it may be separate from the battery charging circuit 54. Battery protection circuit

[0029] See Figure 3 An undervoltage battery protection circuit 100 is shown, which is operatively connected between battery 16 and electrical load 34. The undervoltage battery protection circuit 100 can be implemented as part of a power steering controller 42, which includes power control circuitry 60. Power control circuitry 60 includes features for controlling the selection of the primary power supply V. ps and battery power supply V bat Which of the circuits supplies power to electrical load 34? At battery voltage V... bat When the voltage drops below an acceptable first voltage level, the undervoltage battery protection circuit 100 detects a low battery output voltage V indicating an undervoltage state of battery 16.bat At that time, the battery voltage V will be... bat Disconnect from electrical load 34, thereby cutting off battery power to electrical load 34. When battery voltage V bat When the voltage is increased to a larger second acceptable voltage level, the battery voltage V bat Reconnect to electrical load 34.

[0030] The undervoltage battery protection circuit 100 includes a battery input terminal 17 for receiving the battery voltage V from the battery 16. bat In one example, the DC voltage of battery 16 is approximately 28 volts. The undervoltage battery protection circuit 100 also has a reference voltage input 19 configured to receive a low battery reference voltage V. ref The undervoltage battery protection circuit 100 also includes a comparator U15, which is used to convert the indicated battery voltage V applied to the first input terminal (-) into a signal. bat The first signal and the indication reference voltage V applied to the second input terminal (+) ref The first signal is compared with the second signal to generate an output indicating whether the battery voltage is high or low. The second signal is obtained by comparing the battery voltage V. bat The first voltage is generated by applying a first resistor divider network containing resistors R175 and R176. The first resistor divider network divides the battery voltage V. bat The voltage divider is a proportional voltage, for example, a voltage in the range of 0 volts to 5 volts. The second signal is a reference voltage V applied to the second resistor divider network (including resistors R173 and R174). ref A proportional second voltage. The second signal voltage is also proportional within, for example, a voltage range of 0 volts to 5 volts.

[0031] The first resistor divider network, consisting of resistors R175 and R176, preferably uses high-resistance resistors. For example, according to one example, resistor R175 has a resistance of approximately 750 kΩ, and resistor R176 has a resistance of approximately 113 kΩ. In this example, the second resistor divider network, consisting of resistors R173 and R174, can also have high resistance values. For example, resistor R173 has a resistance of approximately 100 kΩ, and resistor R174 has a resistance of approximately 150 kΩ. The resistors R175, R176, R173, and R174 forming the first and second resistor divider networks preferably each have sufficiently high resistance values, for example, greater than 50 kΩ. Because of the relatively high resistance values ​​of resistors R175, R176, R173, and R174, the first and second resistor voltage divider networks advantageously absorb very small amounts of current, resulting in less energy consumption, which is particularly advantageous when drawing power from battery 16.

[0032] Comparator U15 will indicate the battery voltage V bat The first voltage is compared with a second voltage indicating a reference voltage Vref. When the first voltage is greater than the second voltage, comparator U15 generates a low output voltage of zero volts. According to one example, for a 28-volt Vref... bat The first voltage can be approximately 5 volts, while the second voltage can be a smaller voltage, representing the battery's undervoltage cutoff voltage dropping to a cutoff voltage of approximately 21 volts. Therefore, comparator U15 detects a battery voltage V of 28 volts. bat When the voltage drops below the 21-volt cutoff, a high output voltage of 5 volts is generated.

[0033] The undervoltage battery protection circuit 100 includes a feedback resistor R172 connected in parallel with comparator U15. This feedback resistor R172 couples the output of comparator U15 to a proportional reference voltage input to create hysteresis. The resistance value of the feedback resistor R172 can be, for example, 168kΩ. The hysteresis provides a dead-time voltage range, such as a 3V dead-time, to prevent the output of comparator U15 from switching between a high and low output signal until the voltage difference at the input of comparator U15 is sufficiently close. For example, when an undervoltage condition is detected, the hysteresis effect requires the battery voltage V... bat The voltage is increased to a higher level (e.g., 24 volts) before comparator U15 can produce a zero-volt low-voltage output, allowing power to be restored to electrical load 34. The undervoltage battery protection circuit 100 includes a battery disconnection circuit, shown as having a battery connection relay K2, which is operable to disconnect the battery voltage applied to one or more electrical loads 34. When comparator U15 outputs a zero-volt low-voltage signal, the battery voltage V... bat This will be applied to one or more electrical loads. When the output of comparator U15 generates a 5-volt high voltage signal, battery disconnection relay K2 will release the battery voltage V. bat Disconnect from one or more electrical loads 34.

[0034] The first and second input terminals of comparator U15 are coupled to capacitors, respectively. For example, the first input terminal (-) is coupled to capacitor C99, and the second input terminal (+) is coupled to capacitor C98. Both capacitors C99 and C98 are grounded, which helps to reduce noise in the input signal to comparator U15, thereby achieving a more stable signal comparison.

[0035] The battery disconnection circuit shown includes a battery connection relay K2, which includes a relay switch S2 and a relay coil C2. When the relay coil C2 is energized, it switches the relay switch S2 from a normally open circuit state to a closed circuit state. The coil C2 of the battery connection relay K2 is connected in parallel with a pair of reverse-connected diodes D24 and D26 to eliminate signal interference from the battery connection relay K2.

[0036] Battery connection relay K2 is coupled to transistors Q4 and Q1, which can be configured as N-type MOSFETs. N-type MOSFET transistor Q4 is coupled to battery latch input 23 via resistor R35 to receive a battery latch signal that turns on transistor Q4 when battery 16 is available to supply power and transistor Q1 is off. Transistor Q1 is coupled to the output of a logic OR gate consisting of a pair of diodes D42. The logic OR gate with diodes D42 has a first input and a second input. The first input is coupled to the output of comparator U15, and the second input is coupled to the Power Supply Good (PS Good) input 31 to receive a Power Supply Good signal indicating the availability of main power supply. When comparator U15 detects battery voltage V... bat In an undervoltage condition where the voltage is below the cutoff voltage, or when the main power supply voltage V... ps Available (Main power supply voltage V) ps When the output (which turns on transistor Q1) is generated, OR gate D42 turns on transistor Q1 across resistors R37 and R22, shorting the signal at battery latch input 23 to ground, thus turning off transistor Q4. This prevents battery 16 from supplying power to electrical load 34.

[0037] When battery 16 is available and comparator U15 detects battery voltage V bat When the voltage is higher than the undervoltage cutoff voltage, and the hysteresis transistor Q1 turns on, which in turn turns on transistor Q4, causing current to flow from the load switching signal L at input terminal 27. s A current flows through relay coil C2 to ground, thus energizing relay coil C2. When relay coil C2 is energized, relay switch S2 forms a closed circuit. When relay switch S2 of relay K2 is closed, the voltage V from the battery... bat The power is supplied through one of the diodes D21 and the fuse F3, thereby supplying the battery voltage V. bat Supply to electrical load 34.

[0038] In addition, it has a voltage V ps The main power supply unit 39 supplies power to another diode D21 via fuse F2, so that the main power supply can supply power to the electrical load 34 when available. When the main power supply V psWhen available, the main power supply V ps This will be used as the power supply for electrical load 34. When the main power supply is unavailable, the Power Good (PS Good) input terminal 31 receives a low voltage signal. When the battery voltage V bat When the voltage drops below the cutoff voltage threshold under under-voltage conditions, transistors Q1 and Q4 turn off to prevent current from flowing through the relay coil C2 of relay K2, thus keeping relay switch S2 in the open position to control the battery voltage V. bat The electrical load 34 is disconnected to prevent further draining of battery 16. When the charge of battery 16 is sufficiently higher than a higher second threshold set by the hysteresis effect, transistors Q1 and Q4 are turned on again to apply current through the relay coil C2 of relay K2, thereby closing relay switch S2 and allowing the battery voltage V to return to normal. bat Reconnect to electrical load 34.

[0039] Therefore, it should be understood that the undervoltage battery protection circuit 100 advantageously provides hysteresis to prevent the battery voltage V from escalating. bat The periodic disconnection and reconnection further depletes battery 16 with minimal or no current draw. It should be understood that the undervoltage battery protection circuit 100 can be used in the patient support device 12 shown and described in this application. It should also be understood that the undervoltage battery protection circuit 100 can be used with rechargeable batteries in other devices to power other electrical loads. Battery charger protection circuit

[0040] Reference Figure 4 A reverse polarity battery charger protection circuit 200 is shown operatively coupled between the battery charger 18 and the battery 16. The reverse polarity battery charger protection circuit 200 may be implemented as part of the battery charger 18 and the battery charging circuit 54, or may be included in a separate module. The battery charger protection circuit 200 receives DC power from the battery charger 18 and supplies DC power to the rechargeable battery 16 connected to the battery connector 50. The battery connector 50 has a pair of terminals, including a first terminal 52A and a second terminal 52B, configured to connect to two terminals of different polarities on the battery 16. For example, the first terminal 52A may be configured to be electrically connected to the positive (+) battery terminal to receive a positive voltage, and the second terminal 52B may be configured to be electrically connected to the negative (-) battery terminal to receive a negative voltage; the second terminal is shown as grounded. Thus, the battery charger 18 can supply a specified voltage, such as 28 volts, at terminals 52A and 52B of the battery connector 50 to charge the battery 16 to a maximum full charge voltage of approximately 28 volts.

[0041] The battery charger protection circuit 200 includes a battery charger input terminal 70 configured to receive charger power supply voltage from the battery charger 18, and a battery connector 50 as an output terminal configured to couple with a first polarity output terminal 52A and a second polarity output terminal 52B, which are in turn connected to the battery 16. The battery charger protection circuit 200 includes a relay K3 coupled in series with the battery charger input terminal 70 and therefore with the battery charger 18. The battery charger protection circuit 200 also includes a diode D40 coupled in parallel with the battery charger 18. The relay K3 includes a relay coil C1 and a relay switch S1. The relay switch S1 is connected in series with the first terminal 52A of the charger 18 and the battery connector 50. The relay K3 coil C1 is coupled in parallel to a pair of reverse-connected diodes D39 and D41 to eliminate signal jitter in the relay K3.

[0042] Relay coil C1 is connected in series with transistor Q18 and diode D40. When the proper polarity connection of the battery is detected, diode D40 and relay K3 allow battery 16 to be charged with battery charger 18, while when the reverse polarity connection of battery 16 to battery connector 50 is detected, charging of battery 16 with battery charger 18 is prevented. It should be understood that diode D40, which is connected in parallel with battery charger 18, is also connected in parallel with relay switch S1 and relay coil C1.

[0043] The battery charger protection circuit 200 also includes resistors R177 and R178 coupled to the main power supply input 75 of the control transistor Q18. The availability of the main power supply Vps is required to turn on transistor Q18, allowing current to flow through diode D40 and relay K3 to ground, thereby charging the battery 16.

[0044] In operation, when battery 16 is connected to battery connector 50 via terminals 52A and 52B according to the appropriate voltage polarity, current flows through diode D40 and relay coil C1, causing relay switch S1 to close, forming a closed circuit between charger 18 and battery 16, thereby allowing battery charger 18 to power battery 16 and charge it to battery voltage Vbat. When battery 16 is connected with reverse polarity, the negative polarity of battery 16 connected to the first terminal 52A does not allow current to flow through diode D40 and relay coil C1, so no current flows into relay coil C1, and therefore relay switch S1 remains in the open position, thereby preventing battery 16 from being charged by battery charger 18.

[0045] By using relay K3 and diode D40 in the circuit configuration, the battery charger protection circuit 200 advantageously prevents the charging of the rechargeable battery 16 through the battery charger 18 when a reverse polarity battery connection is detected. This minimizes the power consumption transmitted through the relay coil C1, whose resistance is, for example, approximately 2.079 kΩ. When no power is available from the main power supply and a reverse polarity battery connection is detected, the battery charger protection circuit 200 disconnects the battery 16 from the charger 18. This protects the charger from reverse polarity connections, eliminates reverse feeds into the circuit, and reduces battery leakage through the charger network. The battery charger protection circuit 200 can be advantageously used on the patient support device 12 as shown and described herein. It should also be understood that the battery charger protection circuit 200 can be used in conjunction with the battery charger and rechargeable battery in other devices to power other electrical loads and charge rechargeable batteries.

[0046] The disclosure herein may be further summarized in the following paragraphs, and is also characterized by any combination of aspects and all aspects of the various aspects described herein.

[0047] According to one aspect of this disclosure, a battery protection circuit includes a battery input configured to receive a battery voltage, a reference voltage input configured to receive a low battery reference voltage, a comparator for comparing a first signal indicating the battery voltage with a second signal indicating the reference voltage and generating an output indicating a low battery voltage, a feedback resistor coupling the output of the comparator to the reference voltage input to generate a hysteresis, and a battery disconnect circuit configured to disconnect the battery voltage applied to an electrical load.

[0048] According to another aspect, the first signal includes a first voltage, and the second signal includes a second voltage.

[0049] According to another aspect, the battery protection circuit also has a first resistor divider network that is coupled to the battery voltage to generate a first voltage.

[0050] According to another aspect, the battery protection circuit also has a second resistor divider network, which is coupled to the reference voltage input to generate a second signal.

[0051] According to another aspect, each of the first and second resistor divider networks in the battery protection circuit has a first resistor and a second resistor. Both the first and second resistors have a resistance greater than 50kΩ.

[0052] According to another aspect, when the first signal exceeds the second signal by the amount of hysteresis, the battery disconnect circuit reconnects the battery voltage to the electrical load.

[0053] According to another aspect, the battery disconnection circuit includes a relay configured to disconnect the battery from the electrical load.

[0054] According to another aspect, the battery disconnection circuit has an OR logic circuit that receives the output of the comparator and the main power supply signal.

[0055] On the other hand, the battery is configured for use in the bed to power one or more electric devices.

[0056] According to another aspect, the battery is a lead-acid battery.

[0057] According to another aspect of this disclosure, a battery system includes a battery, an electrical load, and a battery protection circuit. The battery has one or more battery cells for generating a battery voltage. The electrical load is configured to receive the battery voltage for supplying power to the electrical load. The battery protection circuit includes a battery input configured to receive the battery voltage, a reference voltage input configured to receive a low battery reference voltage, a comparator for comparing a first signal indicating the battery voltage with a second signal indicating the reference voltage and generating a comparator signal indicating a low battery voltage at a comparator output, a feedback resistor coupling the comparator output of the comparator to the reference voltage input to generate hysteresis, and a battery disconnect circuit for disconnecting the battery voltage applied to the electrical load.

[0058] According to another aspect, the first signal includes a first voltage, and the second signal includes a second voltage.

[0059] According to another aspect, the battery system also has a first resistive voltage divider network, which is coupled to the battery voltage to generate a first voltage.

[0060] According to another aspect, the battery system also has a second resistor divider network, which is coupled to the reference voltage input to generate a second signal.

[0061] According to another aspect, each of the first and second resistor divider networks in the battery system has a first resistor and a second resistor. Both the first and second resistors have a resistance greater than 50kΩ.

[0062] According to another aspect, when the first signal exceeds the second signal by the amount of hysteresis, the battery disconnection circuit reconnects the battery voltage to the load.

[0063] According to another aspect, the battery disconnection circuit includes a relay configured to disconnect the battery from the load.

[0064] On another note, the battery system has an OR logic circuit for receiving the comparator output and the override signal.

[0065] On the other hand, the battery is configured for use in the bed to power one or more electric devices.

[0066] According to another source, the battery is a lead-acid battery.

[0067] According to another aspect of the invention, a reverse polarity battery charger protection circuit has a battery charger input configured to receive a charging voltage from the battery charger. A battery connector is configured to be coupled to a first polarity output terminal and a second polarity output terminal of the battery. A relay is coupled in series with the battery charger input. A diode is configured to be coupled in parallel with the battery charger. A transistor is coupled to the relay and the diode, wherein the diode and the relay allow the battery to be charged with the battery charger and prevent the battery from being charged with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

[0068] According to another embodiment, the relay includes a relay coil and a relay switch, wherein current from the battery flows through a diode and the relay coil to close the relay switch, thereby coupling power from the battery charger to the battery.

[0069] On another note, the reverse polarity connection between the battery and the battery connector input prevents current from flowing through the diode and relay coil, causing the relay switch to disconnect the battery charger from the battery.

[0070] According to another aspect, the transistor has an input terminal coupled to the main power supply signal.

[0071] On the other hand, the main power supply unit supplies DC voltage signals.

[0072] According to another aspect, an AC-DC converter can be used to convert AC voltage to DC voltage.

[0073] According to another aspect, the battery is configured for use in the bed to power one or more electric devices.

[0074] According to another source, the battery is a lead-acid battery.

[0075] According to another aspect of this disclosure, a battery charging system includes a battery, a battery charger, and a reverse polarity battery charging protection circuit coupling the battery charger to the battery. The battery has one or more battery cells for generating a battery voltage, and the battery charger generates a charging voltage to charge the battery. The reverse polarity battery charging protection circuit has a battery charger input configured to receive the charging voltage from the battery charger. A battery connector is configured to be coupled to a first polarity output and a second polarity output of the battery. A relay is coupled in series with the battery charger input. A diode is coupled in parallel with the battery charger. A transistor is coupled to the relay and the diode, wherein the diode and the relay allow the battery to be charged with the battery charger and prevent the battery from being charged with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

[0076] According to another aspect, the relay includes a relay coil and a relay switch, wherein current from the battery flows through a diode and the relay coil to close the relay switch, thereby coupling power from the battery charger to the battery.

[0077] On another note, the reverse polarity connection between the battery and the battery connector input prevents current from flowing through the diode and relay coil, causing the relay switch to disconnect the battery charger from the battery.

[0078] On the other hand, the transistor has an input terminal coupled to the main power supply signal.

[0079] On the other hand, the main power supply unit supplies DC voltage.

[0080] According to another aspect, the battery charging system also has an AC-DC converter for converting AC voltage to DC voltage.

[0081] According to another aspect, the battery is configured for use in the bed to power one or more electric devices.

[0082] According to another source, the battery is a lead-acid battery.

[0083] Those skilled in the art will understand that the construction of the described disclosure and other components is not limited to any particular material. Unless otherwise stated herein, other exemplary embodiments of the disclosure herein can be formed from a variety of materials.

[0084] For the purposes of this disclosure, the term "coupled" (including all its forms, couple, coupling, coupled, etc.) generally refers to the direct or indirect connection between two components (electrical or mechanical components). This connection can be static or movable. Such a connection can be achieved by integrally molding the two components (electrical or mechanical) and any additional intermediate members together or integrally molding them together. Unless otherwise stated, such a connection can be permanent, detachable, or removable.

[0085] As used herein, the term "about" indicates that quantities, sizes, formulations, parameters, and other quantities and characteristics are not and need not be precise, but may be approximate and / or larger or smaller as needed. This reflects tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. When the term "about" is used to describe the endpoints of a numerical value or range, this disclosure should be understood to include the specific numerical value or endpoint referred to. Regardless of whether the endpoints of a numerical value or range in the specification use "about," the endpoints of that numerical value or range are intended to include two implementations: one modified by "about" and one not modified by "about." It should also be understood that each endpoint of a range is significant, both related to and independent of another endpoint.

[0086] As used herein, the terms “substantially,” “basically,” and variations thereof are intended to indicate that the feature is equal to or approximately equal to a certain value or description. For example, a “substantially flat” surface is intended to indicate a flat or approximately flat surface. Furthermore, “substantially” is intended to indicate that two values ​​are equal or approximately equal. In some embodiments, “substantially” may indicate that the difference between values ​​is within about 10%, for example, within about 5%, or within about 2%.

[0087] It should also be noted that, as shown in the exemplary embodiments, the construction and arrangement of the components in this disclosure are for reference only. Although this disclosure describes only a few embodiments of the present invention in detail, those skilled in the art will readily understand upon reading this disclosure that many modifications can be made (e.g., variations in the size, dimensions, structure, shape, and proportions of various components; variations in parameter values; variations in installation arrangements; variations in the materials used; variations in color; variations in orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter. For example, an component that appears as a single piece may be composed of multiple parts, or components that appear as multiple parts may be integrally formed; the docking operation may be reversed or otherwise changed; the structure and / or components, connectors, or other elements of the system may be changed; the nature or number of adjustment positions provided between components may be changed. It should be noted that the components and / or assemblies of the system may be made of any of a variety of materials that provide sufficient strength or durability and may have a variety of colors, textures, and combinations. Therefore, all such modifications are intended to be covered within the scope of the present invention. Other substitutions, modifications, alterations, and omissions may be made to the design, operating conditions, and arrangement of the desired embodiments and other exemplary embodiments without departing from the spirit of the present invention.

[0088] It should be understood that any of the described processes or steps within those processes may be combined with other disclosed processes or steps to form a structure within the scope of this disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes only and should not be considered as limiting.

Claims

1. A battery protection circuit, the battery protection circuit comprising: A battery input terminal, configured to receive battery voltage; A reference voltage input terminal, configured to receive a low battery reference voltage; A comparator is used to compare a first signal indicating the battery voltage with a second signal indicating the reference voltage and generate an output indicating a low battery voltage; A feedback resistor couples the output of the comparator to the reference voltage input to produce hysteresis; as well as A battery disconnect circuit configured to disconnect the battery voltage applied to an electrical load.

2. The battery protection circuit according to claim 1, wherein, The first signal includes a first voltage, and the second signal includes a second voltage.

3. The battery protection circuit according to claim 2, further comprising a first resistor divider network, the first resistor divider network being coupled to the battery voltage to generate a first voltage.

4. The battery protection circuit according to claim 3, further comprising a second resistor divider network coupled to the reference voltage input to generate the second signal.

5. The battery protection circuit according to claim 4, wherein, Each of the first resistor divider network and the second resistor divider network includes a first resistor and a second resistor, wherein both the first resistor and the second resistor have a resistance value greater than 50kΩ.

6. The battery protection circuit according to any one of claims 1 to 5, wherein, When the first signal exceeds the second signal by the amount of hysteresis, the battery disconnection circuit reconnects the battery voltage to the electrical load.

7. The battery protection circuit according to claim 6, wherein, The battery disconnection circuit includes a relay configured to disconnect the battery from the electrical load.

8. The battery protection circuit according to claim 1, further comprising an OR logic circuit, wherein the OR logic circuit receives the output of the comparator and the main power supply signal.

9. The battery protection circuit according to any one of claims 1 to 8, wherein, The battery is configured for use in the bed to power one or more electric devices.

10. The battery protection circuit according to any one of claims 1 to 9, wherein, The battery is a lead-acid battery.

11. A battery system, the battery system comprising: A battery having one or more battery cells for generating a battery voltage; An electrical load configured to receive a battery voltage for supplying power to the electrical load; as well as Battery protection circuit, the battery protection circuit includes: A battery input terminal, configured to receive battery voltage; A reference voltage input terminal, configured to receive a low battery reference voltage; A comparator is used to compare a first signal indicating the battery voltage with a second signal indicating the reference voltage and generate a comparator signal indicating a low battery voltage at the comparator output. A feedback resistor, which couples the comparator output of the comparator to the reference voltage input to produce a hysteresis; and A battery disconnect circuit is provided to disconnect the battery voltage applied to the electrical load.

12. The battery system according to claim 11, wherein, The first signal includes a first voltage, and the second signal includes a second voltage.

13. The battery system of claim 12, further comprising a first resistor divider network coupled to the battery voltage to generate the first voltage.

14. The battery system of claim 13, further comprising a second resistor divider network coupled to the reference voltage input to generate the second signal.

15. The battery system according to claim 14, wherein, Each of the first resistor divider network and the second resistor divider network includes a first resistor and a second resistor, wherein both the first resistor and the second resistor have a resistance greater than 50kΩ.

16. The battery system according to any one of claims 11 to 15, wherein, When the first signal exceeds the second signal by the amount of hysteresis, the battery disconnection circuit reconnects the battery voltage to the load.

17. The battery system according to claim 16, wherein, The battery disconnection circuit includes a relay configured to disconnect the battery from the load.

18. The battery system of claim 11, further comprising an OR logic circuit for receiving the output of the comparator and an override signal.

19. The battery system according to any one of claims 11 to 18, wherein, The battery is configured for use in the bed to power one or more electric devices.

20. The battery system according to any one of claims 11 to 19, wherein, The battery is a lead-acid battery.

21. A reverse polarity battery charger protection circuit, the reverse polarity battery charger protection circuit comprising: A battery charger input terminal, configured to receive a charging voltage from a battery charger; A battery connector configured to couple to a first polarity output terminal and a second polarity output terminal of a battery; A relay, wherein the relay is coupled in series with the input terminal of the battery charger; A diode, the diode being configured to be coupled in parallel with the battery charger; as well as A transistor coupled to the relay and the diode, wherein the diode and the relay allow the battery to be charged with the battery charger and prevent the battery from being charged with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

22. The reverse polarity battery charger protection circuit according to claim 21, wherein, The relay includes a relay coil and a relay switch, wherein current from the battery flows through the diode and the relay coil to close the relay switch, thereby coupling power from the battery charger to the battery.

23. The reverse polarity battery charger protection circuit according to claim 22, wherein, The reverse polarity connection between the battery and the input terminal of the battery connector prevents current from flowing through the diode and the relay coil, thereby causing the relay switch to disconnect the battery charger from the battery.

24. The reverse polarity battery charger protection circuit according to claim 21, wherein, The transistor has an input terminal coupled to the main power supply signal.

25. The reverse polarity battery charger protection circuit according to claim 24, wherein, The main power supply unit supplies DC voltage signals.

26. The reverse polarity battery charger protection circuit according to claim 25, wherein the reverse polarity battery charger protection circuit further comprises an AC-DC converter for converting AC voltage to DC voltage.

27. The reverse polarity battery charger protection circuit according to any one of claims 21 to 26, wherein, The battery is configured for use in the bed to power one or more electric devices.

28. The reverse polarity battery charger protection circuit according to any one of claims 21 to 27, wherein the battery is a lead-acid battery.

29. A battery charging system, the battery charging system comprising: A battery having one or more battery cells for generating a battery voltage; A battery charger, wherein the battery charger is used to generate a charging voltage to charge the battery; as well as A reverse polarity battery charging protection circuit, wherein the reverse polarity battery charging protection circuit is used to couple the battery charger to the battery, the reverse polarity battery charging protection circuit comprising: A battery charger input terminal, configured to receive a charging voltage from the battery charger; A battery connector configured to couple to a first polarity output terminal and a second polarity output terminal of the battery; A relay, wherein the relay is coupled in series with the input terminal of the battery charger; A diode, wherein the diode is coupled in parallel with the battery charger; and A transistor coupled to the relay and the diode, wherein the diode and the relay allow the battery to be charged with the battery charger and prevent the battery from being charged with the battery charger when a reverse polarity connection between the battery and the battery connector is detected.

30. The battery charging system according to claim 29, wherein, The relay includes a relay coil and a relay switch, wherein current from the battery flows through the diode and the relay coil to close the relay switch, thereby coupling power from the battery charger to the battery.

31. The battery charging system according to claim 30, wherein, The reverse polarity connection between the battery and the input terminal of the battery connector prevents current from flowing through the diode and the relay coil, thereby causing the relay switch to disconnect the battery charger from the battery.

32. The battery charging system according to claim 29, wherein, The transistor has an input terminal coupled to the main power supply signal.

33. The battery charging system according to claim 32, wherein, The main power supply unit supplies DC voltage.

34. The battery charging system of claim 33, further comprising an AC-DC converter for converting AC voltage to DC voltage.

35. The battery charging system according to any one of claims 29 to 34, wherein, The battery is configured for use in the bed to power one or more electric devices.

36. The battery charging system according to any one of claims 29 to 35, wherein, The battery is a lead-acid battery.

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