WO2022074019A1

WO2022074019A1 - Control circuitry for negative pressure wound treatment apparatuses

Info

Publication number: WO2022074019A1
Application number: PCT/EP2021/077476
Authority: WO
Inventors: Mark John ELLERINGTON; Benjamin James GARDNER; Natasha Rose MIDDLETON; Samuel John MORTIMER; Felix Clarence Quintanar; Fraser George WEEDON
Original assignee: T.J.Smith And Nephew,Limited
Priority date: 2020-10-06
Filing date: 2021-10-05
Publication date: 2022-04-14
Also published as: GB202015790D0

Abstract

A negative pressure wound therapy device can include a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing. Electronic control circuitry can include at least one voltage comparator. The electronic control circuitry configured to by the at least one voltage comparator, to generate at least one signal that controls operation of the negative pressure source and apply the at least one signal to control operation of the negative pressure source. The at least one signal can be generated based on an output from a sensor.

Description

CONTROL CIRCUITRY FOR NEGATIVE PRESSURE WOUND TREATMENT APPARATUSES

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Great Britain Patent Application No. 2015790.5, filed October 6, 2020, which is hereby incorporated by reference in its entirety and made part of this disclosure.

Technical Field

Embodiments described herein relate to apparatuses, systems, and methods for the treatment of wounds, for example using dressings in combination with negative pressure wound therapy.

Description of the Related Art

Many different types of wound dressings are known for aiding in the healing process of a human or animal. These different types of wound dressings include many different types of materials and layers, for example, gauze, pads, foam pads or multi-layer wound dressings. Topical negative pressure (TNP) therapy, sometimes referred to as vacuum assisted closure, negative pressure wound therapy, or reduced pressure wound therapy, is widely recognized as a beneficial mechanism for improving the healing rate of a wound. Such therapy is applicable to a broad range of wounds such as incisional wounds, open wounds, and abdominal wounds or the like. TNP therapy assists in the closure and healing of wounds by reducing tissue edema, encouraging blood flow, stimulating the formation of granulation tissue, removing excess exudates and may reduce bacterial load. Thus, reducing infection to the wound. Furthermore, TNP therapy permits less outside disturbance of the wound and promotes more rapid healing.

SUMMARY

A negative pressure wound therapy device can include a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing; and electronic control circuitry comprising at least one voltage comparator, the electronic control circuitry configured to, by the at least one voltage comparator, generate at least one signal that controls operation of the negative pressure source, the at least one signal generated based on an output from a sensor, and apply the at least one signal to control operation of the negative pressure source.

The negative pressure wound therapy device of any of the preceding paragraphs and/or any of the apparatuses, systems, or devices disclosed herein can include one or more of the following features. The output from the sensor can comprise a voltage value or the electronic control circuitry can be configured to convert the output from the sensor to the voltage value. The sensor can comprise a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator can be configured to generate the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of target pressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source. The sensor can comprise a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator can be configured to generate the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source. The sensor can comprise a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator can be configured to generate the at least one signal responsive to the output from the pressure sensor not satisfying a low and high pressure thresholds indicative of pressure in the fluid flow path being within a target pressure range, the at least one signal causing activation of the negative pressure source. The at least one voltage comparator can comprise first and second voltage comparators and the at least one signal can comprise first and second signals, the first voltage comparator configured to generate the first signal that controls operation of the negative pressure source, and the second voltage comparator configured to generate the second signal responsive to a power source capacity satisfying a threshold indicative of a low power source capacity. The electronic control circuitry can be further configured to provide an indication of an operating condition responsive to generation of the at least one signal. The electronic control circuitry does not include a programmable controller. The device can be configured to provide therapy to a single patient. A method of operating a negative pressure wound therapy device can include by electronic control circuitry of comprising at least one voltage comparator, by the at least one voltage comparator, generating at least one signal that controls operation of a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing, the at least one signal generated based on an output from a sensor; and applying the at least one signal to control operation of the negative pressure source.

The method of operating a negative pressure wound therapy device of any of the preceding paragraphs and/or any of the apparatuses, systems, or devices disclosed herein can include one or more of the following features. The output from the sensor can comprise a voltage value or the electronic control circuitry is configured to convert the output from the sensor to the voltage value. The sensor can comprise a pressure sensor measuring pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of target pressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source. The sensor can comprise a pressure sensor measuring pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source. The sensor can comprise a pressure sensor measuring a pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor not satisfying a low and high pressure thresholds indicative of pressure in the fluid flow path being within a target pressure range, the at least one signal causing activation of the negative pressure source. The at least one voltage comparator can comprise first and second voltage comparators and the at least one signal comprises first and second signals, the first voltage comparator generating the first signal that controls operation of the negative pressure source, and the second voltage comparator generating the second signal responsive to a power source capacity satisfying a threshold indicative of a low power source capacity. The method can further comprise, by electronic control circuitry, providing an indication of an operating condition responsive to generation of the at least one signal. The electronic control circuitry does not include a programmable controller.

Disclosed are methods of operating a negative pressure wound therapy device of any of the preceding paragraphs and/or any of the apparatuses, systems, or devices disclosed herein.

Any of the features, components, or details of any of the arrangements or embodiments disclosed in this application, including without limitation any of the apparatus embodiments and any of the negative pressure wound therapy embodiments disclosed herein, are interchangeably combinable with any other features, components, or details of any of the arrangements or embodiments disclosed herein to form new arrangements and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a negative pressure wound therapy system.

Figures 2A and 2B illustrate a negative pressure wound therapy device and canister.

Figure 3 illustrates a schematic of a negative pressure wound therapy device.

Figures 4A, 4B, and 4C illustrate a negative pressure wound therapy device.

Figure 5 illustrates the pressure over time of a negative pressure wound therapy device.

Figure 6A illustrates electronic control circuitry.

Figure 6B illustrates a voltage comparator.

Figure 7 illustrates electronic control circuitry that prevents overpressure.

Figure 8 illustrates electronic control circuitry that controls a negative pressure source to supply pressure in a range of pressures.

Figure 9 illustrates electronic control circuitry that controls a negative pressure source.

Figure 10 illustrates components of the electronic circuitry of Figure 9.

DETAILED DESCRIPTION

Embodiments disclosed herein relate to systems and methods of monitoring or treating a wound. Throughout this specification reference is made to a wound. The term wound is to be broadly construed and encompasses open and closed wounds in which skin is torn, cut or punctured or where trauma causes a contusion, or any other superficial or other conditions or imperfections on the skin of a patient or otherwise that benefit from pressure treatment. A wound is thus broadly defined as any damaged region of tissue where fluid may or may not be produced. Examples of such wounds include, but are not limited to, abdominal wounds or other large or incisional wounds, either as a result of surgery, trauma, sterniotomies, fasciotomies, or other conditions, dehisced wounds, acute wounds, chronic wounds, subacute and dehisced wounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions, contusions, bums, diabetic ulcers, pressure ulcers, stoma, surgical wounds, trauma and venous ulcers or the like.

Embodiments of systems and methods disclosed herein can be used with topical negative pressure (“TNP”) or reduced pressure therapy systems. Briefly, negative pressure wound therapy assists in the closure and healing of many forms of “hard to heal” wounds by reducing tissue oedema, encouraging blood flow and granular tissue formation, or removing excess exudate and can reduce bacterial load (and thus infection risk). In addition, the therapy allows for less disturbance of a wound leading to more rapid healing. TNP therapy systems can also assist in the healing of surgically closed wounds by removing fluid. TNP therapy can help to stabilize the tissue in the apposed position of closure. A further beneficial use of TNP therapy can be found in grafts and flaps where removal of excess fluid is important and close proximity of the graft to tissue is required in order to ensure tissue viability.

As used herein, reduced or negative pressure levels, such as -X mmHg, represent pressure levels relative to normal ambient atmospheric pressure, which can correspond to 760 mmHg (or I atm, 29.93 inHg, 101.325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure value of -X mmHg reflects pressure that is X mmHg below 760 mmHg or, in other words, a pressure of (760-X) mmHg. In addition, negative pressure that is “less” or “smaller” than X mmHg corresponds to pressure that is closer to atmospheric pressure (for example, -40 mmHg is less than -60 mmHg). Negative pressure that is “more” or “greater” than -X mmHg corresponds to pressure that is further from atmospheric pressure (for example, -80 mmHg is more than -60 mmHg). In some cases, local ambient atmospheric pressure is used as a reference point, and such local atmospheric pressure may not necessarily be, for example, 760 mmHg. Systems and methods disclosed herein can be used with other types of treatment in addition to or instead of reduced pressure therapy, such as irrigation, ultrasound, heat or cold, neuro stimulation, or the like. In some cases, disclosed systems and methods can be used for wound monitoring without application of additional therapy. Systems and methods disclosed herein can be used in conjunction with a dressing, including with compression dressing, reduced pressure dressing, or the like.

A healthcare provider, such as a clinician, nurse, or the like, can provide a TNP prescription specifying, for example, the pressure level or time of application. However, the healing process is different for each patient and the prescription may affect the healing process in a way the clinician or healthcare provider did not expect at the time of devising the prescription. A healthcare provider may try to adjust the prescription as the wound heals (or does not heal), but such process may require various appointments that can be time consuming and repetitive. Embodiments disclosed herein provide systems, devices, or methods of efficiently adjusting TNP prescriptions and delivering effective TNP therapy.

Wound Therapy System

Figure 1 illustrates a negative pressure wound treatment system 100 (sometimes referred to as a reduced pressure wound therapy system, a TNP system, or a wound treatment system) comprising a wound filler 130 placed inside a wound cavity 110, the wound cavity 110 sealed by a wound cover 120. The wound filler 130 in combination with the wound cover 120 can be referred to as a wound dressing. A conduit 140 (such as a single or multi lumen tube) is connected the wound cover 120 with a wound therapy device 150 (sometimes as a whole or partially referred to as a “pump assembly”) configured to supply reduced or negative pressure. The wound cover 120 can be in fluidic communication with the wound cavity 110.

With any of the systems disclosed herein, a wound therapy device can be canisterless (meaning that exudate is collected in the wound dressing or is transferred via the conduit 140 for collection to another location). However, any of the wound therapy devices disclosed herein can include or support a canister.

Additionally, with any of the wound therapy systems disclosed herein, any of the wound therapy devices can be mounted to or supported by the wound dressing, or adjacent to the wound dressing. The wound filler 130 can be any suitable type, such as hydrophilic or hydrophobic foam, gauze, inflatable bag, and so on. The wound filler 130 can be conformable to the wound cavity 110 such that it substantially fills the wound cavity 110. The wound cover 120 can provide a substantially fluid impermeable seal over the wound cavity 110. In some cases, the wound cover 120 has a top side and a bottom side, and the bottom side adhesively (or in any other suitable manner) seals with the wound cavity 110. The conduit 140 or any other conduit disclosed herein can be formed from polyurethane, PVC, nylon, polyethylene, silicone, or any other suitable material.

The wound cover 120 can have a port (not shown) configured to receive an end of the conduit 140. In some cases, the conduit 140 can otherwise pass through or under the wound cover 120 to supply reduced pressure to the wound cavity 110 so as to maintain a desired level of reduced pressure in the wound cavity 110. The conduit 140 can be any suitable article configured to provide at least a substantially sealed fluid flow pathway or path between the wound therapy device 150 and the wound cover 120, so as to supply the reduced pressure provided by the wound therapy device 150 to wound cavity 110.

The wound cover 120 and the wound filler 130 can be provided as a single article or an integrated single unit. In some cases, no wound filler is provided and the wound cover by itself may be considered the wound dressing. The wound dressing may then be connected, via the conduit 140, to a source of negative pressure of the wound therapy device 150. In some cases, though not required, the wound therapy device 150 can be miniaturized and portable, although larger conventional negative pressure sources (or pumps) can also be used.

The wound cover 120 can be located over a wound site to be treated. The wound cover 120 can form a substantially sealed cavity or enclosure over the wound site. The wound cover 120 can have a film having a high water vapour permeability to enable the evaporation of surplus fluid, and can have a superabsorbing material contained therein to safely absorb wound exudate. In some cases, the components of the TNP systems described herein can be particularly suited for incisional wounds that exude a small amount of wound exudate.

The wound therapy system can operate with or without the use of an exudate canister. The wound therapy system can support an exudate canister. In some cases, configuring the wound therapy device 150 and conduit 140 so that the conduit 140 can be quickly and easily removed from the wound therapy device 150 can facilitate or improve the process of wound dressing or pump changes, if necessary. Any of the pump assemblies disclosed herein can have any suitable connection between the conduit 140 and the pump.

The wound therapy device 150 can deliver negative pressure of approximately -80 mmHg, or between about -20 mmHg and -200 mmHg. Note that these pressures are relative to normal ambient atmospheric pressure thus, -200 mmHg would be about 560 mmHg in practical terms. In some cases, the pressure range can be between about -40 mmHg and -150 mmHg. Alternatively, a pressure range of up to -75 mmHg, up to -80 mmHg or over -80 mmHg can be used. Also in some cases a pressure range of below -75 mmHg can be used. Alternatively, a pressure range of over approximately -100 mmHg, or even -150 mmHg, can be supplied by the wound therapy device 150.

The wound therapy device 150 can provide continuous or intermittent negative pressure therapy. Continuous therapy can be delivered at above 0 mmHg, -25 mmHg, -40 mmHg, -50 mmHg, -60 mmHg, -70 mmHg, -80 mmHg, -90 mmHg, -100 mmHg, -120 mmHg, -140 mmHg, -160 mmHg, -180 mmHg, -200 mmHg, or below -200 mmHg. Intermittent therapy can be delivered between low and high negative pressure set points (sometimes referred to as setpoint). Low set point can be set at above 0 mmHg, -25 mmHg, - 40 mmHg, -50 mmHg, -60 mmHg, -70 mmHg, -80 mmHg, -90 mmHg, -100 mmHg, -120 mmHg, -140 mmHg, -160 mmHg, -180 mmHg, or below -180 mmHg. High set point can be set at above -25 mmHg, -40 mmHg, -50 mmHg, -60 mmHg, -70 mmHg, -80 mmHg, -90 mmHg, -100 mmHg, -120 mmHg, -140 mmHg, -160 mmHg, -180 mmHg, -200 mmHg, or below -200 mmHg. During intermittent therapy, negative pressure at low set point can be delivered for a first time duration, and upon expiration of the first time duration, negative pressure at high set point can be delivered for a second time duration. Upon expiration of the second time duration, negative pressure at low set point can be delivered. The first and second time durations can be same or different values.

In operation, the wound filler 130 can be inserted into the wound cavity 110, and wound cover 120 can be placed so as to seal the wound cavity 110. The wound therapy device 150 can provide negative pressure to the wound cover 120, which may be transmitted to the wound cavity 110 via the wound filler 130. Fluid (such as, wound exudate) can be drawn through the conduit 140 and stored in a canister. In some cases, fluid is absorbed by the wound filler 130 or one or more absorbent layers (not shown). Wound dressings that may be utilized with the pump assembly and systems of the present application include Renasys-F, Renasys-G, Renasys AB, and Pico Dressings available from Smith & Nephew. Further description of such wound dressings and other components of a negative pressure wound therapy system that may be used with the pump assembly and systems of the present application are found in U.S. Patent Publication Nos. 2012/0116334, 2011/0213287, 2011/0282309, 2012/0136325 and U.S. Patent No. 9,084,845, each of which is incorporated by reference in its entirety. In some cases, other suitable wound dressings can be utilized.

Figures 2 A and 2B illustrates a negative pressure wound therapy device 200 (sometimes referred to as a wound therapy device) including a pump assembly 230 and a canister 220. As illustrated, the pump assembly 230 and the canister 220 can be connected, thereby forming the wound therapy device 200. The pump assembly 230 can include one or more indicators, such as visual indicator 202 configured to indicate alarms and visual indicator 204 configured to indicate status of the pump assembly 230. The visual indicators 202 and 204 can alert a user (for example, patient, health care provider, or the like) to a variety of operating or failure conditions of the pump assembly 230, including alerting the user to normal or proper operating conditions, pump failure, power supplied to the pump or power failure, detection of a leak within the wound cover or flow pathway (sometimes referred to as fluid flow path), suction blockage in the flow pathway, canister full, overpressure, or any other similar or suitable conditions or combinations thereof. Any one or more suitable indicators can be additionally or alternatively used, such as visual, audio, tactile indicator, and so on.

The pump assembly 230 can include a display 206 (such as a screen) mounted in a recess formed in a case of the pump assembly 230. The display 206 can be a touch screen display. The display 206 can support playback of audiovisual (AV) content, such as instructional videos, and render a number of screens or graphical user interfaces (GUIs) for configuring, controlling, and monitoring the operation of the pump assembly 230. The pump assembly 230 can include one or more strap mounts 226 for connecting a carry strap to the pump assembly 230 or for attaching a cradle. The canister 220 may be replaced with another canister, such as when the canister 220 has been filled with fluid. The pump assembly 230 can include butons 212 (such as keys) that allow the user to operate and monitor the operation of the pump assembly 230. One of the butons 212 can operate as a power button to turn on/off the pump assembly 230. Another of the buttons 212 can operate as a play/pause buton for the delivery of therapy.

The canister 220 can hold fluid (such as, exudate) removed from the wound cavity 110. The canister 220 includes one or more latches for ataching the canister to the pump assembly 230. For example, the canister 220 as illustrated can have a capacity of 300 mL and include graduations. The canister 220 can include a tubing channel for connecting to the conduit 140.

Figure 2B illustrates a rear view 200B of the pump assembly 230 and the canister 220. The pump assembly 230 can include a speaker 232 for producing sound. The speaker 232 can generate an acoustic alarm in response to deviations in therapy delivery, non- compliance with therapy delivery, or any other similar or suitable conditions or combinations thereof.

The pump assembly 230 can include a filter access door 234 for accessing and replacing one or more filters, such as antibacterial filters. The pump assembly 230 can comprise a power jack 239 for charging and recharging an internal batery of the pump assembly. The pump assembly 230 can include a disposable power source, such as batteries, so that no power jack is needed.

Figure 3 illustrates a schematic of a control system 300 which can be employed in the wound monitoring or treatment systems described herein, such as in the wound therapy device 200 of Figures 2A and 2B. Electrical components can operate to accept user input, provide output to the user, operate the pressure source, provide network connectivity, and so on. A first processor can be responsible for user activity, and a second processor can be responsible for controlling another device, such as a pump 390.

Input and output to the other device, such as a pump 390, one or more sensors (for example, one or more pressure sensors 325 configured to monitor pressure in one or more locations of the fluid flow path), or the like, can be controlled by an input/output (I/O) module 320. For example, the I/O module can receive data from one or more sensors through one or more ports, such as serial (for example, I2C), parallel, hybrid ports, and the like. The processor 310 can receive data from and provide data to one or more expansion modules 360, such as one or more USB ports, SD ports, Compact Disc (CD) drives, DVD drives, FireWire ports, Thunderbolt ports, PCI Express ports, and the like. The processor 310, along with other controllers or processors, can store data in memory 350 (such as one or more memory modules), which can be internal or external to the processor 310. Any suitable type of memory can be used, including volatile or non-volatile memory, such as RAM, ROM, magnetic memory, solid-state memory, Magnetoresistive random-access memory (MRAM), and the like.

The processor 310 can be a general purpose controller, such as a low-power processor, or an application specific processor. The processor 310 can be configured as a “central” processor in the electronic architecture of the control system 300, and the processor 310 can coordinate the activity of other processors, such as a pump control processor 370, communications processor 330, and one or more additional processors 380. The processor 310 can run a suitable operating system, such as a Linux, Windows CE, VxWorks, etc.

The pump control processor 370 can control the operation of a pump 390, which can generate negative or reduced pressure. The pump 390 can be a suitable pump, such as a diaphragm pump, peristaltic pump, rotary pump, rotary vane pump, scroll pump, screw pump, liquid ring pump, diaphragm pump operated by a piezoelectric transducer, voice coil pump, and the like. The pump control processor 370 can measure pressure in a fluid flow path, using data received from one or more pressure sensors 325, calculate the rate of fluid flow, and control the pump. The pump control processor 370 can control the pump motor so that a desired level of negative pressure in achieved in the wound cavity 110. The desired level of negative pressure can be pressure set or selected by the user. The pump control processor 370 can control the pump (for example, pump motor or another transducer) using pulse-width modulation (PWM). A control signal for driving the pump can be a 0-100% duty cycle PWM signal. The pump control processor 370 can perform flow rate calculations and detect alarms. The pump control processor 370 can communicate information to the processor 310. The pump control processor 370 can be a low-power processor.

A communications processor 330 can provide wired or wireless connectivity. The communications processor 330 can utilize one or more transceivers 340 for sending and receiving data. The one or more transceivers 340 can include one or more antennas, optical sensors, optical transmitters, vibration motors or transducers, vibration sensors, acoustic sensors, ultrasound sensors, or the like. The communications processor 330 can provide one or more of the following types of connections: Global Positioning System (GPS), cellular connectivity (for example, 2G, 3G, LTE, 4G, 5G, or the like), near field communication (NFC), Bluetooth connectivity, radio frequency identification (RFID), wireless local area network (WLAN), wireless personal area network (WPAN), WiFi connectivity, Internet connectivity, optical connectivity (for example, using infrared light, barcodes, such as QR codes, etc.), acoustic connectivity, ultrasound connectivity, or the like. Connectivity can be used for various activities, such as pump assembly location tracking, asset tracking, compliance monitoring, remote selection, uploading of logs, alarms, and other operational data, and adjustment of therapy settings, upgrading of software or firmware, pairing, and the like.

The communications processor 330 can provide dual GPS/cellular functionality. Cellular functionality can, for example, be 3G, 4G, or 5G functionality. The communications processor 330 can communicate information to the processor 310. The communications processor 330 can include internal memory or can utilize memory 350. The communications processor 330 can be a low-power processor.

The control system 300 can store data, such as GPS data, therapy data, device data, and event data. This data can be stored, for example, in memory 350. This data can include patient data collected by one or more sensors. The control system 300 can track and log therapy and other operational data. Such data can be stored, for example, in the memory 350.

Using the connectivity provided by the communications processor 330, the control system 300 can upload any of the data stored, maintained, or tracked by the control system 300 to a remote computing device. The control system 300 can also download various operational data, such as therapy selection and parameters, firmware and software patches and upgrades, and the like. The one or more additional processors 380, such as processor for controlling one or more user interfaces (such as, one or more displays), can be utilized. In some cases, any of the illustrated or described components of the control system 300 can be omitted depending on an embodiment of a wound monitoring or treatment system in which the control system 300 is used. Any of the negative pressure wound therapy devices described herein can include one or more features disclosed in U.S. Patent No. 9,737,649 or U.S. Patent Publication No. 2017/0216501, each of which is incorporated by reference in its entirety.

Canisterless Pump Assembly

Figures 4 A, 4B, and 4C illustrate perspective, front, and rear views of a negative pressure wound therapy device 400 (sometimes referred to as a wound therapy device). The wound therapy device 400 can include a housing 402 and a mounting component 410 (such as an attachment). The mounting component 410 can be removably attached to the housing 402, such that the wound therapy device 400 can be used with or without the mounting component 410. For example, Figure 4C illustrates the wound therapy device 400 without the mounting component 410. The mounting component 410 can be designed to allow the wound therapy device 400 to be mounted on another object such as, but not limited to, a user’s person. The mounting component 410 can include a clip 404 designed to retain the mounting component 410 on a user’s outerwear, such as on a user’s pocket, a pouch, a belt, a flap, or otherwise.

The housing 402 (sometimes referred to as “outer housing”) can contain or support components of the wound therapy device 400. The housing 402 can be formed from one or more portions, such as a front portion 402A and a rear portion 402B, which can be removably attached to form the housing 402.

The housing 402 can include a user interface 412 which can be designed to provide a user with information (for example, information regarding an operational status of the wound therapy device 400). The user interface 412 can include one or more indicators, such as icons 414, which can alert the user to one or more operating or failure conditions of the reduced pressure wound therapy system.

The wound therapy device 400 can include one or more user input features, such as button 416, designed to receive an input from the user for controlling the operation of the wound therapy device 400. A single button can be present which can be used to activate and deactivate the reduced pressure wound therapy device or control other operating parameters of the wound therapy device 400. The wound therapy device 400 can include a connector 430 for connecting a tube or conduit to the wound therapy device 400. The connector 430 can be used to connect the wound therapy device 400 to a wound dressing.

The wound therapy device 400 can be a canisterless device. The wound dressing can retain fluid (such as, exudate) aspirated from the wound. Such a dressing can include a filter, such as a hydrophobic filter, that prevents passage of liquids downstream of the wound dressing (toward the wound therapy device 400).

The wound therapy device 400 can include a cover 418, as illustrated in Figure 4C and which can be removable. The cover 418 can cover a cavity (not shown) in which one or more power sources, such as batteries, for powering the wound therapy device 400 are positioned.

The wound therapy device 400 can include one or more controllers or other electronic components described herein. The wound therapy device 400 can be similar to the Pico negative pressure wound therapy device manufactured by Smith & Nephew.

Any of the negative pressure wound therapy devices described herein can include one or more features disclosed in U.S. Patent Publication No. 2019/0231939, U.S. Patent No. 8,734,425 titled, “PRESSURE CONTROL APPARATUS” and issued May 27, 2014, U.S. Patent No. 8,905,985 titled, “SYSTEMS AND METHODS FOR CONTROLLING OPERATION OF A REDUCED PRESSURE THERAPY SYSTEM’ and issued December 9, 2014, U.S. Patent No. 9,084,845 titled, “REDUCED PRESSURE THERAPY APPARATUSES AND METHODS OF USING SAME” and issued July 21, 2015, U.S. Patent No. 9,427,505 titled, “NEGATIVE PRESSURE WOUND THERAPY APPARATUSE” and issued August 30, 2016, U.S. Patent No. 10,737,002, titled “PRESSURE SAMPLING SYSTEMS AND METHODS FOR NEGATIVE PRESSURE WOUND THERAPY” and issued on August 11, 2020, which are incorporated by reference in their entireties.

Electronic Control Circuitry

As described previously, the negative pressure source and associated electronics can be controlled with controllers or processors that control the operation of the pump, provide feedback to the user through indicators (such as, visual indicators), monitor the system through a pressure sensor, respond to user interaction of a button, or log various device states to memory storage. Processors, microprocessors, controllers, or microcontrollers (sometimes collectively referred to as microcontrollers) can be programmable by instructions, such as software or firmware instructions. In some cases, a microcontroller can add cost to the manufacturing of the device and to the development process in the form of software development activities. Additionally or alternatively, the microcontroller could be prone to failure (and can cause the device to fail), for instance, as a result of vulnerability to electrostatic and mechanical effects. As an example, software or firmware code stored in memory could be corrupted (such as, from exposure to electromagnetic radiation). In some cases, to overcome these vulnerabilities and to lower the cost, electronic control circuitry that does not utilize a microcontroller can be used to control the operation of the negative pressure source and/or other electronic components.

The negative pressure source can be controlled to provide negative pressure wound therapy by alternating periods of activation and deactivation of the negative pressure source. Figure 5 illustrates the alternating periods of activation and deactivation of the negative pressure source. The wound therapy device 400 can be configured to operate in accordance with Figure 5. In some cases, the device can be configured to make a transition from a standby state (in which the negative pressure source is deactivated, as is illustrated by the segment 522 in Figure 5) to an initial pump down (“IPD”) state or mode (in which the negative pressure source is activated for delivery of therapy, as is illustrated by the segment 524 in Figure 5) in response to receiving a signal or automatically (such as, due to a timeout). For example, the signal can be provided as a result of the user pressing a button to start, suspend, and/or restart therapy. In some cases, the device can monitor the duration of time the device remains in the standby state. This can be accomplished, for example, by maintaining a timer (in firmware, software, hardware or any combination thereof), which can be reset and started when the device transitions into the standby state. The device can automatically make the transition from the standby state to the IPD state when the time duration exceeds a threshold (e.g., times out).

Responsive to achieving the negative pressure set point, the negative pressure source can be deactivated (shown as a valley 526 in the negative pressure graph in Figure 5). The device can transition from the IPD state to a maintenance state (sometimes referred to as a maintenance pump down or MPD state or mode) in response to a determination that a negative pressure set point has been achieved. In the MPD state, the negative pressure source can be periodically activated to reestablish the negative pressure set point (or another desired negative pressure target). This is illustrated in Figure 5 by the segment 530 and other similar segments. Operation in the MPD state is further explained below. As is illustrated in Figure 5, negative pressure can be maintained in the range between -90 mmHg (or less or more) and -70 mmHg (or less or more).

Electronic control circuitry can interpret and respond to various events and control the operation of the negative pressure source. For example, the loss of pressure (illustrated by the segment 528 in Figure 5) would result in the electronic control circuitry sensing (through a pressure sensor) and activating the negative pressure source to resume negative pressure wound therapy. In another case, the electronic circuitry can detect a low capacity of the power source (such as, voltage) and provide an indication (such as, by activating/signaling the "battery low" indicator). One or more pressure sensors can be used to provide information that can control the operation of the negative pressure source or other electronic components. For example, a first pressure sensor can be used to measure and/or monitor pressure at the wound (such as, underneath the wound dressing), which can be accomplished by measuring and/or monitoring pressure in a fluid flow path connecting the negative pressure source and the wound. A second pressure sensor can be used to measure and/or monitor pressure external to the wound dressing. The second pressure sensor can measure pressure external to the wound dressing, which can be relative atmospheric pressure since the atmospheric pressure varies depending on, for instance, an altitude relative to the sea level or pressurized environment in which device may be used. These measurements can be used to establish a desired negative pressure differential (or set point) at the wound relative to the external pressure. In some cases, a relative pressure sensor that measures pressure relative to the surrounding environment can be used.

Electronic control circuitry can control the supply of negative pressure by the negative pressure source according at least to a comparison between a pressure monitored by a first pressure sensor (or wound pressure) and the pressure monitored by a second pressure sensor (or external pressure) (or based on pressure from the relative pressure sensor). Electronic control circuity can operate the negative pressure source in a first mode (or IPD mode) in which the negative pressure source is activated to establish the negative pressure set point at the wound. The set point can be set to, for example, a value in the range between about -70 mmHg to about -90 mmHg, among others. Once the set point has been established, which can be verified based on the readings from one or more pressure sensors, electronic control circuitry can deactivate (or pause) operation of the negative pressure source. Electronic control circuitry can operate the negative pressure source in a second mode (or MPD mode) in which the negative pressure source is periodically activated to re-establish the negative pressure set point (or another negative pressure level) when the wound is depressurized as a result of one or more leaks. Electronic control circuitry can activate the negative pressure source in response to the pressure at the wound (as monitored by the one or more pressure sensors) becomes more positive than a negative pressure threshold, which can be set to the same negative pressure as the set point or lower negative pressure (or more positive pressure).

Electronic control circuitry can utilize one or more comparators, such as voltage comparators. When used in conjunction with a pressure sensor, a voltage comparator can generate an output signal responsive to a difference between input signals (or an input signal and a reference voltage) satisfying a threshold. The output signal can be used to turn the negative pressure source on or off. For example, this could drive the core functionality of the device by only deactivating the negative pressure source when the pressure level has been sensed to meet the negative pressure set point, such as -80mmHg (or more or less).

The negative pressure source can deliver negative pressure to a wound covered by a wound dressing as described herein. Electronic control circuitry can use one or more voltage comparators to generate signal(s) that control operation of the negative pressure source. The signal(s) can be based on an output from a sensor. For example, the sensor can be a pressure sensor (or a plurality of pressure sensors) measuring pressure in the fluid flow path. The electronic circuitry can utilize the signal to control the operation of the negative pressure source.

Figure 6A illustrates electronic control circuitry 500. The output of a sensor (or a plurality of sensors) can be connected to the track or line 512. In some cases, the sensor can be a pressure sensor used to measure pressure in the fluid flow path between the negative pressure source and the wound. In some cases, the output of the sensor can indicate remaining capacity of the power source (for example, voltage). The line 512 can serve as an input to a comparator, such as a voltage comparator 516. The voltage comparator 516 can be a single-input voltage comparator that compares the input voltage to a reference voltage. A voltage divider 514 with resistors R(A) and R(B) can be used to scale voltage on the line 512 to be suitable for comparing to the reference voltage. For example, assuming that the reference voltage is 0.2V and the negative pressure set point of -80 mmHg corresponds to a IV output by the pressure sensor. The two resistors R(A) and R(B) can be selected such that the output voltage of the pressure sensor of IV is scaled to at least a 0.2V voltage for inputting into the comparator 516 to trigger the comparator. Assuming that pressure sensor output voltage is V(s), the output of the voltage divider feeding the comparator is:

V(out) = R(A)/(R(A)+R(B)) x V(s)

From this equation and several values of V(s), values of R(A) and R(B) can be determined.

The voltage comparator 516 can compare the scaled sensor output voltage to the reference voltage. The voltage comparator 516 can generate an output signal based on the results of the comparison. For example, the output signal of the voltage comparator 516 can be logic high (or low) responsive to the scaled output from the sensor satisfying the reference voltage. For example, the voltage comparator 516 can generate an output signal responsive to the negative pressure set point being attained.

The output of the comparator 516 can drive an electronic switch 518 (such as, a transistor). The switch 518 can directly or via additional circuitry (such as, one or more logic gates) turn the negative pressure source on or off. For example, the switch 518 can cause the negative pressure source to turn off responsive to reaching the negative pressure set point in the IPD mode.

In some cases, multiple comparators could be used in tandem to provide multiple functions whilst looking for different conditions.

Figure 6B illustrates a comparator 600, which is illustrated as an op amp comparator. The comparator 600 can have two inputs Vi and V2. First input can correspond to the reference voltage and the second input can be the sensor voltage. V_out is the output of the comparator 600. The comparator 600 can be used in place of the compotator 516.

In some cases, the electronic control circuitry can detect and prevent overpressure. Figure 7 illustrates electronic control circuitry 700 that detects and prevents overpressure. The output of a sensor can be connected to track or line 712. In some cases, the output of the sensor can be a voltage value or the electronic control circuitry can convert the output from the sensor to the voltage value. The sensor can be a pressure sensor (or a plurality of pressure sensors) used to measure pressure, for instance, in the fluid flow path between the negative pressure source and the wound.

As in Figure 6A, the sensor output signal can pass through a voltage divider 714 and be input into a voltage comparator 716. The voltage comparator 716 can compare the scaled pressure sensor output signal to a reference voltage to detect overpressure. For example, overpressure can be detected when pressure in the fluid flow path reaches -150 mmHg (or less or more). The voltage comparator 716 can output a signal based on the results of the comparison. In this example, the output signal of the voltage comparator 716 can be responsive to the output from a pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path. The output of the voltage comparator 716 can drive an electronic switch 718 (such as, a transistor). The switch 718 can directly or via additional circuitry (such as, one or more logic gates) deactivate the negative pressure source, or other components, to promote patient safety. For example, responsive to the detection of overpressure, the switch 718 can be deactivated thereby blocking return path for the current (for instance, blocking path to ground). Therefore, detection of overpressure can cause deactivation of the negative pressure source.

During the MPD mode, the device can advantageously monitor and maintain the pressure, for instance, in a fluid flow path between the negative pressure source and a wound dressing, within a target pressure range (or operating range). For example, in some cases, during the MPD mode, pressure in the fluid flow path can be maintained between a high pressure threshold and a low pressure threshold as shown in Figure 5. For example, the high pressure threshold can be approximately -70 mmHg (or less or more). In some embodiments, the high pressure threshold can be between approximately -40 mmHg and approximately -200 mmHg, between approximately -60 mmHg and approximately -100 mmHg, between approximately -70 mmHg and -80 mmHg, approximately -71 mmHg, approximately -67 mmHg, any value or subrange within these ranges, or any other value as desired. The low pressure threshold can be approximately -90 mmHg (or less or more). In some embodiments, the low pressure threshold during the MPD mode can be the same as the negative pressure set point used in the IPD mode. In some embodiments, the low pressure threshold during the MPD mode can be different from the negative pressure set point used in the IPD mode.

In some case, one or more comparators can be used to implement the MPD mode. For example, two voltage comparators can be used. A first voltage comparator can be used for the low pressure threshold, and the second voltage comparator can be used for the high pressure threshold. The first voltage comparator can be used to deactivate the negative pressure source. The second voltage comparator can be used to activate the negative pressure source. A single window voltage comparator can be used in place of the first and second voltage comparators.

Figure 8 illustrates electronic control circuitry 800 that controls a negative pressure source to supply pressure in a range of pressures. Figure 8 illustrates a dual voltage comparator 816 that can be used to detect that the negative pressure in the fluid flow path is within a threshold. The dual voltage comparator 816 can be used to receive two input signals and compare the signals individually to two reference voltages and the comparator can output two signals (one from each individual comparison). For example, as described herein, in the MPD mode the negative pressure is maintained between high and low pressure thresholds. In some cases, the electronic control circuitry can detect that the negative pressure is within a threshold and prevent activation of the negative pressure source. With reference to Figure 8, the output of a sensor is illustrated as 812. In some cases, the output of the sensor can be a voltage value or the electronic control circuitry can convert the output from the sensor to the voltage value. The sensor can be a pressure sensor (or a plurality of pressure sensors) used to measure pressure, for instance, in the fluid flow path between the negative pressure source and the wound.

Similarly to Figure 6A, the sensor output 812 can pass through a voltage divider 814 to generate two inputs (INA+ and INB-) for the voltage comparator 816. The voltage comparator 816 can compare the scaled (by the voltage divider) pressure sensor output to a reference voltage to determine if the pressure is above (or more positive than) the high pressure threshold. The voltage comparator 816 can compare the scaled pressure sensor output to a reference voltage to determine if the pressure is below (or more negative than) the low pressure threshold. For example, negative pressure can be maintained in the range between -70 mmHg and -90 mmHg. In this example, the output two signals (OUTA and OUTB) of the voltage comparator 816 can be responsive to the output from a pressure sensor satisfying the high or low pressure thresholds. The output of the voltage comparator 816 can drive an electronic switch 818 (such as, a transistor). The switch 818 can directly or via additional circuitry (such as, one or more logic gates) activate or deactivate the negative pressure source. The voltage comparator can output a logic high signal (or similar signal) to activate the switch 818 (such as, turn on the transistor) responsive to detecting that the pressure sensor output is greater (or more positive) than the high pressure threshold (such as, between 0 mmHg and -70 mmHg). In turn, the negative pressure source can be activated to reestablish the low pressure threshold as illustrated in Figure 5 and described herein. Detection by the voltage comparator 816 that the pressure sensor output is less (or more negative) than the low pressure threshold (such as, less than -90 mmHg) can cause the voltage comparator 816 to output a logic low signal (or similar signal) to deactivate the switch 818 (for instance, turn off the transistor). In turn, the negative pressure source can be deactivated. When the pressure measured by the pressure sensor is between -70 mmHg to -90 mmHg, the voltage comparator 816 can continue to output a logic high signal such that the switch 818 remains active.

OUTA output signal can be indicative of the result of comparison with the high pressure threshold, and OUTB output signal can be indicative of the result of comparison with the low pressure threshold (or vice versa). As is illustrated in Figure 8, both OUTA and OUTB output signals can be connected to the switch via a common line. In such arrangement, if either OUTA or OUTB (or both) are a logic low signal (or similar signal), the switch 818 would be deactivated.

Alternatively or additionally, one or more voltage comparators similar to the voltage comparator 816 can be used to control (such as, activate or deactivate) other components within the device. For example, a voltage comparator and a switch (similar to the switch 818) can be used to control a user interface, for example, activate or deactivate a visual indicator (such as, an LED) or another indicator (such as, audible or tactile indicator). Therefore, any description herein for logic or circuits to drive a motor, pump motor, or negative pressure sources could also be used to drive any other components, such as one or more components of a user interface.

Although the voltage comparator 816 is illustrated as a dual voltage comparator, the voltage comparator 816 (or any of the dual voltage comparators disclosed herein) can be replaced with two single voltage comparators. In some cases, a window comparator can combine the other functions or applications described herein in a single component. Electronic control circuitry can control one or more of the negative pressure source or other functionality of the device without need for a microcontroller. In some cases, a microcontroller could be used and dedicated to other tasks, such as user interface, data management, or communication. In some instances, microcontroller can be used to provide redundant control. In some cases, the device would function without the use of memory. As noted previously, when a device uses memory, the memory could be corrupted causing failure of the device. Therefore, it could be helpful to provide a device that can control the operation of electronics without using memory.

A voltage comparator can additionally or alternatively be used to detect low (or depleted) capacity of the power source. As described herein, electronic control circuitry can control the negative pressure source and detect power source capacity. For example, a first voltage comparator can generate a first signal that controls operation of the negative pressure source. A second voltage comparator can generate a second signal responsive to a power source capacity satisfying a threshold indicative of a low (or depleted) power source capacity. In some cases, the electronic control circuitry can provide an indication of an operating condition. The indication can be an alarm or light (for example, LED) indicators to notify the user of a low battery condition.

Electronic control circuitry can include a plurality of comparators and other components (such as, switches) for controlling multiple functions or responding to various operating conditions. For example, electronic control circuitry can perform one or more of controlling the negative pressure source to establish and maintain negative pressure, detecting and reacting to overpressure, detecting and reacting to blockage, detecting and reacting to a leak, detecting and reacting to a low (or depleted) power source, or the like.

Figure 9 illustrates electronic control circuitry that controls a negative pressure source. The circuitry of Figure 9 incorporates one or more dual voltage comparators 916, 926 that can be used to detect that the negative pressure is within a desired range, as described in more detail with reference to Figure 8. The circuitry of Figure 9 can also incorporate electronic control circuitry with one or more voltage comparators 936 that detects and prevents overpressure as described in more detail with reference to Figure 7.

The electronic control circuitry of Figure 9 can include a pressure control system with a voltage comparator 916 that operates similar to the voltage comparator 816 in Figure 8. For example, if the voltage comparator detects a pressure greater than the high pressure threshold (such as, between 0 mmHg -70 mmHg), the voltage comparator 916 can activate the switch 918A in order to attempt to activate the negative pressure source 950. Detection of the pressure less than the low pressure threshold (such as, less than -90 mmHg) can cause the switch 918A to be deactivated to deactivate the negative pressure source. When the pressure measured by the pressure sensor is between -70 mmHg to -90 mmHg there is no change in state in the switch 918 A.

The pressure control system 902 (which can include the voltage comparator 916 and the switch 918A) can be used in parallel with a redundant pressure control system 904. The redundant pressure control system 904 can include a voltage comparator 926 that operates similar to the voltage comparator 916 and a switch 918B that operates similar to the switch 918A. The redundant pressure control system 904 can provide control of the negative pressure source even if the pressure control system 902 fails (or vice versa). For example, if the pressure control system 902 fails and the switch 918A cannot be activated to activate the negative pressure source, the redundant pressure control system 904 could take over and activate the switch 918B to activate the negative pressure source. Accordingly, pressure control systems 902 and 904 can independently control the negative pressure source.

The switches 918A and 918B of the pressure control system 902 and redundant pressure control system 904 can be in electrical communication with a switch 918C of the overpressure detection circuit 906. The overpressure detection circuit 906 can operate similar to the overpressure detection circuit described in Figure 7. The pressure signal can be compared a threshold pressure with use of the voltage comparator 936. In this example, as in the detection circuit described in Figure 7, the output signal of the voltage comparator 936 can be generated responsive to the output from a pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path. The output of the voltage comparator 936 can drive the electronic switch 918C (such as, a transistor). As shown in Figure 9, when the overpressure detection circuit is used in series with the pressure control system 902 and redundant pressure control system 904, detection of overpressure can cause deactivation of the negative pressure source regardless of the output of the pressure control system 902 and redundant pressure control system 904. This is because the switch 918C can provide return path for the current (or path to the ground). Accordingly, when the switch 918C is deactivated due to the voltage comparator 936 detecting overpressure, there is would be no return path for the current and current would not flow to the negative pressure source regardless of the state of the switches 918A and 918B. The switch 918C can be active by default, and become deactivated responsive to the voltage comparator 936 detecting overpressure.

Figure 10 illustrates components of the electronic circuitry of Figure 9 shown conceptually. The pressure sensor 1012 provides input to the pressure control system 902, redundant pressure control system 904, and overpressure detection circuit 906. As shown in Figure 10, the negative pressure source 950 is in electrical communication with the pressure control system 902, redundant pressure control system 904, and overpressure detection circuit 906 to activate or deactivate the negative pressure source (such as, the motor or transducer) as described in Figure 9. The pressure control system 902 and redundant pressure control system 904 can be electrically connected in parallel in order to provide independent control of the negative pressure source. The overpressure detection circuit 1004 can be connected to the pressure control systems 902 and 904 in series in order to deactivate the negative pressure source responsive to detection of overpressure.

In some cases, one of the pressure control systems 902 or 904 can be omitted. The overpressure detection circuit 906 can be connected in series to the remaining pressure control system.

Electronic control circuitry that uses one or more voltage comparators can be more efficient than a microcontroller because the electronic control circuitry can consume less power. As a result, operational life can be extended. For example, the system with the voltage comparator could work when the rest of the device has died or is underpowered. This could facilitate relaying this critical power information to the user with relatively low power in the system. In some cases, a voltage comparator can be used to sense an unwanted voltage state across another component that would signify a potential error or fault.

Electronic control circuitry can utilize one or more comparators without a microcontroller. In some cases, electronic control circuitry can be used alone or in combination with a microcontroller to control the device. Electronic control circuitry can be used with a microcontroller to provide a fail-safe or level of redundancy. For example, if the software or microcontroller fails, electronic control circuitry can step in and control the negative pressure wound therapy system. In some cases, electronic control circuitry can be used to drive the core function of the device and a microcontroller can be used to control the user interface (such as, one or more indicators). In certain cases, electronic control circuitry can be used to drive the core function of the system and the user interface and a microcontroller can log and monitor what the device is doing. For example, the microcontroller can act as a black box recorder and may not be vital for the device function.

The use of electrical control circuitry can reduce costs by eliminating or reducing the need for a microcontroller as well as providing reliability and safety by reducing or eliminating the concerns of malfunctioning as described herein.

Other Variations

Although some embodiments describe negative pressure wound therapy, the systems, devices, and/or methods disclosed herein can be applied to other types of therapies usable standalone or in addition to TNP therapy. Systems, devices, and/or methods disclosed herein can be extended to any medical device, and in particular any wound treatment device. For example, systems, devices, and/or methods disclosed herein can be used with devices that provide one or more of ultrasound therapy, oxygen therapy, neurostimulation, microwave therapy, active agents, antibiotics, antimicrobials, or the like. Such devices can in addition provide TNP therapy. The systems and methods disclosed herein are not limited to medical devices and can be utilized by any electronic device.

Any of transmission of data described herein can be performed securely. For example, one or more of encryption, https protocol, secure VPN connection, error checking, confirmation of delivery, or the like can be utilized.

Any value of a threshold, limit, duration, etc. provided herein is not intended to be absolute and, thereby, can be approximate. In addition, any threshold, limit, duration, etc. provided herein can be fixed or varied either automatically or by a user. Furthermore, as is used herein relative terminology such as exceeds, greater than, less than, etc. in relation to a reference value is intended to also encompass being equal to the reference value. For example, exceeding a reference value that is positive can encompass being equal to or greater than the reference value. In addition, as is used herein relative terminology such as exceeds, greater than, less than, etc. in relation to a reference value is intended to also encompass an inverse of the disclosed relationship, such as below, less than, greater than, etc. in relations to the reference value.

Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of protection. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. For example, the actual steps and/or order of steps taken in the disclosed processes may differ from those shown in the figure. Depending on the embodiment, certain of the steps described above may be removed, others may be added. For instance, the various components illustrated in the figures may be implemented as software and/or firmware on a processor, controller, ASIC, FPGA, and/or dedicated hardware. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure.

User interface screens illustrated and described herein can include additional and/or alternative components. These components can include menus, lists, buttons, text boxes, labels, radio buttons, scroll bars, sliders, checkboxes, combo boxes, status bars, dialog boxes, windows, and the like. User interface screens can include additional and/or alternative information. Components can be arranged, grouped, displayed in any suitable order.

Conditional language used herein, such as, among others, “can,” “could”, “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Further, the term “each,” as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term “each” is applied. Additionally, the words “herein,” “above,” "below," and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application.

Conjunctive language, such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is to be understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z, or a combination thereof. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z to each be present. Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

Unless otherwise explicitly stated, articles such as “a” or “an” should generally be interpreted to include one or more described items. Accordingly, phrases such as “a device configured to” are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations.

Although the present disclosure includes certain embodiments, examples and applications, it will be understood by those skilled in the art that the present disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof, including embodiments which do not provide all of the features and advantages set forth herein. Accordingly, the scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments herein, and may be defined by claims as presented herein or as presented in the future.

Claims

WHAT IS CLAIMED IS:

1. A negative pressure wound therapy device comprising: a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing; and an electronic control circuitry comprising at least one voltage comparator, the electronic control circuitry configured to: by the at least one voltage comparator, generate at least one signal that controls operation of the negative pressure source, the at least one signal generated based on an output from a sensor; and control operation of the negative pressure source using the at least one signal; wherein the sensor comprises a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator is configured to generate the at least one signal responsive to the output from the pressure sensor being within a target pressure range between low and high pressure thresholds, the at least one signal causing activation of the negative pressure source.

2. The negative pressure wound therapy device of claim 1, wherein the electronic control circuitry further comprises a switch connected to the at least one voltage comparator and the negative pressure source, the switch being activated by the at least one signal.

3. The negative pressure wound therapy device of any of the preceding claims, wherein the at least one voltage comparator comprises a dual voltage comparator configured to compare the output of the pressure sensor to the low and high pressure thresholds and output two signals responsive to the comparison.

4. The negative pressure wound therapy device of any of the preceding claims, wherein the at least one signal comprises first and second signals, and wherein the at least one voltage comparator comprises a first voltage comparator configured to generate the first signal and a second voltage comparator configured to generate the second signal, the first and second voltage comparators operating independently.

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5. The negative pressure wound therapy device of any of claim 4, wherein the electronic control circuitry further comprises a first switch connected to the first voltage comparator and the negative pressure source and a second switch connected to the second voltage comparator and the negative pressure source, wherein a first circuitry comprising the first voltage comparator and the first switch is connected in parallel to a second circuitry comprising the second voltage comparator and the second switch.

6. The negative pressure wound therapy device of any of the preceding claims, wherein the electronic control circuitry further comprises a third voltage comparator configured to generate at least one another signal responsive to the output from the pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path, the at least one another signal of the third voltage comparator causing deactivation of the negative pressure source.

7. The negative pressure wound therapy device of claim 6, wherein the electronic control circuitry further comprises another switch connected to the third voltage comparator and the negative pressure source, the another switch being controlled by the at least one another signal.

8. The negative pressure wound therapy device of claim 7, wherein the third voltage comparator and the another switch form a third circuitry, and wherein the third circuitry is connected in series to the first circuitry and the second circuitry.

9. The negative pressure wound therapy device of any of the preceding claims, wherein the electronic control circuitry is further configured to provide an indication of an operating condition responsive to generation of the at least one signal.

10. The negative pressure wound therapy device of any of the preceding claims, wherein the electronic control circuitry does not include a programmable controller.

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11. The negative pressure wound therapy device of any of the preceding claims, wherein the device is configured to provide therapy to a single patient.

12. A system comprising the negative pressure wound therapy device of any of the preceding claims and the wound dressing.

13. A negative pressure wound therapy device comprising: a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing; and electronic control circuitry comprising at least one voltage comparator, the electronic control circuitry configured to: by the at least one voltage comparator, generate at least one signal that controls operation of the negative pressure source, the at least one signal generated based on an output from a sensor; and apply the at least one signal to control operation of the negative pressure source.

14. The negative pressure wound therapy device of claim 13, wherein the output from the sensor comprises a voltage value or the electronic control circuitry is configured to convert the output from the sensor to the voltage value.

15. The negative pressure wound therapy device of any of claims 13-14, wherein the sensor comprises a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator is configured to generate the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of target pressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source.

16. The negative pressure wound therapy device of any of claims 13-15, wherein the sensor comprises a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator is configured to generate the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source.

17. The negative pressure wound therapy device of any of claims 13-16, wherein the sensor comprises a pressure sensor configured to measure pressure in the fluid flow path, and wherein the at least one voltage comparator is configured to generate the at least one signal responsive to the output from the pressure sensor not satisfying a low and high pressure thresholds indicative of pressure in the fluid flow path being within a target pressure range, the at least one signal causing activation of the negative pressure source.

18. The negative pressure wound therapy device of any of claims 13-17, wherein the at least one voltage comparator comprises first and second voltage comparators and the at least one signal comprises first and second signals, the first voltage comparator configured to generate the first signal that controls operation of the negative pressure source, and the second voltage comparator configured to generate the second signal responsive to a power source capacity satisfying a threshold indicative of a low power source capacity.

19. The negative pressure wound therapy device of any of claims 13-18, wherein the electronic control circuitry is further configured to provide an indication of an operating condition responsive to generation of the at least one signal.

20. The negative pressure wound therapy device of any of claims 13-19 wherein the electronic control circuitry does not include a programmable controller.

21. The negative pressure wound therapy device of any of claims 13-20, wherein the device is configured to provide therapy to a single patient.

22. A system comprising the negative pressure wound therapy device of any of claims 13-21 and the wound dressing.

23. A method of operating a negative pressure wound therapy device, the method comprising: by electronic control circuitry of comprising at least one voltage comparator: by the at least one voltage comparator, generating at least one signal that controls operation of a negative pressure source configured to deliver, via a fluid flow path, negative pressure to a wound covered by a wound dressing, the at least one signal generated based on an output from a sensor; and applying the at least one signal to control operation of the negative pressure source.

24. The method of any of claim 23, wherein the output from the sensor comprises a voltage value or the electronic control circuitry is configured to convert the output from the sensor to the voltage value.

25. The method of any of claims 23-24, wherein the sensor comprises a pressure sensor measuring pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of target pressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source.

26. The method of any of claims 23-25, wherein the sensor comprises a pressure sensor measuring pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor satisfying a threshold indicative of overpressure being attained in the fluid flow path, the at least one signal causing deactivation of the negative pressure source.

27. The method of any of claims 23-26, wherein the sensor comprises a pressure sensor measuring a pressure in the fluid flow path, and wherein the at least one voltage comparator generates the at least one signal responsive to the output from the pressure sensor not satisfying a low and high pressure thresholds indicative of pressure in the fluid flow path being within a target pressure range, the at least one signal causing activation of the negative pressure source.

28. The method of any of claims 23-27, wherein the at least one voltage comparator comprises first and second voltage comparators and the at least one signal comprises first and second signals, the first voltage comparator generating the first signal that controls operation of the negative pressure source, and the second voltage comparator

-33- generating the second signal responsive to a power source capacity satisfying a threshold indicative of a low power source capacity.

29. The method of any of claims 23-28, further comprising, by electronic control circuitry, providing an indication of an operating condition responsive to generation of the at least one signal.

30. The method of any of claims 23-29, wherein the electronic control circuitry does not include a programmable controller.

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