Electrical stimulus system

Abstract

An electrical stimulus system is disclosed in the field of electrical stimulus delivery to animals or humans, addressing the technical problem of determining the measure of success of stimulus application without direct current measurement, or measurements on the high voltage side. The system measures voltage decay during the electrical stimulus. By comparing the time it takes for the measured voltage to get to a reference voltage with a predefined time, operational characteristics can be inferred, such as the measure of success of the shock to the animal or human. The system may adjust operational parameters accordingly, making it suitable for applications like electric fence energisers and wearable animal devices for containment, shifting, or training purposes.

Description

[0001] ELECTRICAL STIMULUS SYSTEM

[0002]

[0001] The present invention relates to a system for determining a measure of success or load of an electrical stimulus across an electrode pair. More particularly but not exclusively, it relates to a system and method for counting the elapsed time for the voltage to decay over the primary side of a transformer to infer the load across the secondary side of the transformer.

[0003] BACKGROUND OF THE INVENTION

[0004]

[0002] Electric fence energisers and animal shock collars are commonly used in agricultural and security applications to control people and animal movement. These devices function by delivering high- voltage stimuli through a fence or directly to an animal, creating a deterrent effect. The safety and effectiveness of these systems depend on accurate measurement and control of the output energy, especially when the energy exceeds regulatory thresholds such as 1 millijoule.

[0005]

[0003] Traditionally, prior art devices monitor the voltage and / or current at the output terminals, which operate at high voltages often exceeding several kilovolts. This method presents several challenges. High-voltage measurements pose significant safety hazards to both users and the circuitry. The risk of electrical arcing and circuit burnout increases with high-voltage exposure, necessitating the use of specialised, high-voltage-rated components. Components capable of handling high voltages are typically larger and more expensive. This makes it difficult to design compact, cost-effective devices, which may be useful for applications like animal shock collars that require lightweight and portable designs.

[0006]

[0004] Prior art attempts to address these issues have included various methods. One approach involves incorporating additional windings on the transformer to facilitate measurements. This can complicate the transformer design. A further strategy is designing devices that operate below regulatory energy thresholds to avoid the need for high energy measurement systems. However, this limits the effectiveness of the device in applications requiring higher energy outputs.

[0007]

[0005] Having a high or low load across the outputs of a stimulus device significantly affects the voltage and current characteristics of an electrical stimulus device, such as an electric fence energiser or an animal shock collar. The load impedance determines how energy is transferred from the primary to the secondary side of the transformer, influencing both the performance of the device and its compliance with regulatory standards. When the load across an electrode pair connected to the secondary side has high impedance, it means there is minimal current flow through the secondary side. In this scenario, the voltage across the secondary side reaches its maximum because there is little voltage drop due to current flow. The transformer essentially operates under open-circuit conditions on the secondary side, leading to higher voltages at the output terminals. While this might seem advantageous for ensuring a strong deterrent effect in applications like electric fences, it poses significant safety risks. High voltages can lead to arcing, unintended shocks, or safety concerns for animals or people. This is a situation where regulations require the stimulus device to reduce the output voltage when a low-load condition is present.

[0008]

[0006] Conversely, when the load impedance is low indicating that a load is present across the electrode pair, such as an animal making contact with the fence or with a collar electrode pair, the current flow through the secondary side increases. This increased current causes a voltage drop across the transformer and any series resistances, resulting in a lower voltage across the secondary side delivered to the load.

[0009]

[0007] A need remains for a safe, cost-effective, and compact method to measure load impedance or contact conditions in high-energy electrical stimulus devices.

[0010] OBJECT OF THE INVENTION

[0011]

[0008] It is an object of the present invention to provide a system that overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice.

[0012] SUMMARY OF THE INVENTION

[0013]

[0009] In a first aspect, the invention broadly relates to an electrical stimulus system configured to apply an electrical stimulus to a being, the system comprising: a capacitor circuit; a power source; an output transformer having a primary' winding connected to the capacitor circuit by a trigger switch, and a secondary winding configured to output the electrical stimulus across an electrode pair once triggered by the trigger switch; and a control circuit configured to: control an electrical stimulus comprising discharging of the capacitor; during discharging, determine an elapsed time between a voltage of the capacitor falling between a first voltage and a reference voltage based on the first voltage; and determine an operational characteristic of the electrical stimulus based on the determined elapsed time.

[0014]

[0010] In a second aspect, the invention broadly relates to an electrical stimulus system configured to apply an electrical stimulus to a being, the system comprising: a capacitor circuit; a power source; an output transformer having a primary winding connected to the capacitor circuit by a trigger switch, and a secondary winding configured to output the electrical stimulus across an electrode pair once triggered by the trigger switch; and a control circuit configured to: control a first electrical stimulus comprising discharging of the capacitor; during discharging, determine an elapsed time between a voltage of the capacitor falling between a first voltage and a reference voltage based on the first voltage; determine an operational characteristic of the electrical stimulus based on the determined elapsed time; and control a second electrical stimulus based on the determined operational characteristic.

[0015]

[0011] In one embodiment, the embodiments of the second aspect also relate to the first aspect.

[0016]

[0012] In one embodiment, the control circuit is further configured to control stimulus output based on operation of the trigger switch.

[0017]

[0013] In one embodiment, the one or more operational characteristics are related to one or more selected from: voltage across the electrode pair; a measure of success of the electrical stimulus to the being; load across the electrode pair; resistance across the electrode pair; impedance across the electrode pair; a fault across the electrode pair; and arcing from the electrode pair to the being or another object.

[0018]

[0014] In one embodiment, the second electrical stimulus is directly subsequent to the first electrical stimulus with no intervening electrical stimulus,

[0019]

[0015] In one embodiment, the second electrical stimulus is subsequent to the first electrical stimulus with intervening electrical stimulus.

[0020]

[0016] In one embodiment, the first voltage is based on the peak voltage of the capacitor when discharging is initiated.

[0021] 9

[0017] In one embodiment, the peak voltage measurement is taken at the time of triggering of the trigger switch.

[0022]

[0018] In one embodiment, the control circuit is configured to control the voltage of a subsequent electrical stimulus dependent on the one or more operational characteristics.

[0023]

[0019] In one embodiment, the determination of the one or more operational characteristics is based on the elapsed time being above or below a predetermined reference time.

[0024]

[0020] In a further embodiment, an elapsed time below the predetermined reference time corresponds to a successful application of the electrical stimulus to a being present at the electrode pair to receive the electrical stimulus; and a time above the predetermined reference time corresponds to a failed application of the electrical stimulus to a being present or not present at the electrode pair.

[0025]

[0021] In one embodiment, the predetermined reference time for the successful application is between 3 and 4 microseconds.

[0026]

[0022] In one embodiment, the predetermined reference time for the failed application is one selected from: more than 4 microseconds; between 4 and 9 microseconds; or between 6 and 7 microseconds.

[0027]

[0023] In one embodiment, the control circuit is further configured to measure the voltage of the capacitor.

[0028]

[0024] In one embodiment, controlling the charging of the capacitor controls the voltage of the electrical stimulus.

[0029]

[0025] In one embodiment, the controller is configured to apply a second electrical stimulus if the first electrical stimulus was determined to be a failed application.

[0030]

[0026] In one embodiment, the controller is configured to not apply a second electrical stimulus if the first electric stimulus was determined to be a successful application.

[0031]

[0027] In one embodiment, the controller is configured to automatically and subsequently apply the second electrical stimulus if the first electrical stimulus is determined to be a failed application.

[0032]

[0028] In one embodiment, the controller is configured to apply the second electrical stimulus at a higher voltage than the first electrical stimulus if the current electrical stimulus was determined to be a failed application.

[0033]

[0029] In one embodiment, the controller is configured to apply the second electrical stimulus at a higher voltage if the current electrical stimulus was determined to be a failed application.

[0034]

[0030] In one embodiment, the controller is configured to adapt one or more operational parameters of the system based on the successful application or failed application, or elapsed time.

[0035]

[0031] In one embodiment, the controller is configured to adapt one or more operational parameters of the system relating to: the capacitance of the capacitor circuit, the length of the time between charging and discharging the capacitor, energy stored in the capacitor; the first voltage of the capacitor; and / or a change to one or more of the voltage amplitude, current amplitude, period, and frequency of the voltage pulse.

[0036]

[0032] In one embodiment, the one or more operational parameters of the system is the peak voltage the capacitor is charged to.

[0037]

[0033] In one embodiment, the control circuit comprises a controller.

[0038]

[0034] In one embodiment, the controller is configured to record when the successful application or failed application occurs.

[0035] In one embodiment, the controller is configured to associate and record the successful or failed application to a stimulus event relating to the electrical stimulus being applied based on the determined operational characteristic.

[0039]

[0036] In one embodiment, the controller is configured to derive an impedance value dependent on the elapsed time.

[0040]

[0037] In one embodiment, the system comprises a memory device.

[0041]

[0038] In one embodiment, the control circuit further comprises a switch operable to control connection of the capacitor with the power source, and the controller is further configured to operate the switch to control charging of the capacitor by connection to the power source.

[0042]

[0039] In one embodiment, the control circuit is configured to control the trigger switch to discharge the capacitor through the output transformer.

[0043]

[0040] In one embodiment, the reference voltage is a predetermined voltage based on the peak voltage.

[0044]

[0041] In one embodiment, the reference voltage is a predetermined percent of the peak voltage.

[0045]

[0042] In one embodiment, the reference voltage is 75% of the peak voltage.

[0046]

[0043] In one embodiment, the reference voltage is less than 90% and greater than 10% of the peak voltage.

[0047]

[0044] In one embodiment, the reference voltage is chosen to maximise the time difference between ideal open-load and loaded capacitor conditions to get to the same voltage.

[0048]

[0045] In one embodiment, the control circuit comprises an analogue-to-digital converter configured to provide voltage data representative of the voltage measurement.

[0049]

[0046] In one embodiment, the controller is configured to receive said voltage data relating to one or more of the peak voltage and reference voltage.

[0050]

[0047] In one embodiment, the control circuit comprises an analogue-to-digital converter and the controller is configured to send a signal relating to the reference voltage to the digital-to-analogue converter.

[0051]

[0048] In one embodiment, the digital-to-analogue converter is configured to output the reference voltage based on the signal relating to the reference voltage.

[0052]

[0049] In one embodiment, the digital-to-analogue converter is configured to receive a digital input signal relating to the reference voltage from the controller.

[0053]

[0050] In one embodiment, the digital-to-analogue converter is configured to output an analogue output signal relating to the reference voltage to the comparator.

[0054]

[0051] In one embodiment, the control circuit comprises a comparator configured to receive the reference voltage from the digital-to-analogue converter, and provide a comparison output indicating whether the voltage measurement is above or below the reference voltage,

[0055]

[0052] In one embodiment, the comparator is configured to receive an analogue input signal relating to voltage measurement of the capacitor, and an analogue input signal relating to the reference voltage.

[0056]

[0053] In one embodiment, the comparator is configured to output a digital signal to the timer relating to whether the analogue input signal relating to the voltage measurement is less than the analogue output signal relating to the reference voltage.

[0057]

[0054] In one embodiment, the control circuit comprises a timing unit configured to receive the comparison output and output the elapsed time it takes for the voltage measurement of the capacitor to decrease to the reference voltage from the time of the trigger switch being triggered.

[0055] In one embodiment, the control circuit comprises a timing unit configured to output the elapsed time.

[0058]

[0056] In one embodiment, the control circuit comprises a timer to measure the elapsed time.

[0059]

[0057] In one embodiment, the timer is configured to trigger the trigger switch when the timer starts.

[0060]

[0058] In one embodiment, the timer operates at 16 MHz.

[0061]

[0059] In one embodiment, the system comprises a first transformer configured to receive energy directly or indirectly from the power source and step up the voltage of the power source.

[0062]

[0060] In one embodiment, the capacitor comprises a capacitor circuit comprising one or more capacitors configured to store energy from the first transformer at the voltage supplied by the first transformer.

[0063]

[0061] In one embodiment, the capacitor outputs a voltage pulse.

[0064]

[0062] In one embodiment, the output transformer is configured to receive energy stored by the capacitor circuit.

[0065]

[0063] In one embodiment, the controller is configured to control a switch to charge the first transformer.

[0066]

[0064] In one embodiment, the first transformer increases the power source volts to a range between 400 volts and 800 volts.

[0067]

[0065] In one embodiment, the first transformer increases the power source volts to a range between 500 and 700 volts.

[0068]

[0066] In one embodiment, the power source supplies between 20 and 40 watts, and / or 3 and 5 volts, or about 4.2 volts.

[0069]

[0067] In one embodiment, the voltage output by the capacitor is between 100 and 1000 volts, preferably between 250 volts and 650 volts.

[0070]

[0068] In one embodiment, the output transformer is configured to step up the energy stored by the capacitor circuit to a range between 100V and 20kV.

[0071]

[0069] In one embodiment, the ratio of the output transformer is over 15.

[0072]

[0070] In one embodiment, the voltage measuring device provides a scaled -down voltage representative of the voltage drop across the capacitor.

[0073]

[0071] In one embodiment, the voltage measuring device comprises a voltage divider.

[0074]

[0072] In one embodiment, the voltage divider is a frequency compensated voltage divider.

[0075]

[0073] In one embodiment, the voltage divider reduces the voltage by at least 50, 100, 200, or 400.

[0076]

[0074] In one embodiment, the control circuit is configured to only measure the capacitor voltage.

[0077]

[0075] In one embodiment, the control circuit is not configured to measure current.

[0078]

[0076] In one embodiment, the system is integrated into an electric fence energiser for delivering high- voltage stimulus via the electrode pair to an electric fence.

[0079]

[0077] In one embodiment, the system is integrated into a wearable animal device for delivering high- voltage stimulus through the electrode pair positioned to contact or be proximal to an animal in operation,

[0080]

[0078] In one embodiment, the wearable animal device is a collar.

[0081]

[0079] In one embodiment, the electrode pair are or are connected to conductive strands affixed to the collar.

[0082]

[0080] In one embodiment, the being is an animal or person.

[0083]

[0081] In one embodiment, the animal is a large animal over 80kg.

[0082] In one embodiment, the animal is a cattle animal.

[0084]

[0083] In another aspect, a wearable device for a cattle animal comprises the system of any of the above embodiments,

[0085]

[0084] In a third aspect, the invention broadly relates to an electrical stimulus system for a device configured to apply an electrical stimulus, the system comprising: a power source supplying electrical energy: an energy storage component connected to the power source, configured to store the supplied electrical energy; an output transformer having a primary winding connected to the energy storage component, and a secondary winding configured to output high -voltage stimulus upon triggering to an electrode pair across which a load impedance is present; and a control circuit configured to: monitor the voltage decay characteristics of the energy storage component during the discharge of the energy storage component through the primary winding; and infer the load impedance across the secondary winding based on the monitored voltage decay characteristics, wherein: a faster voltage decay indicates a successful application of the electrical stimulus to across the electrode pair; and a slower voltage decay indicates a failed application of the electrical stimulus to across the electrode pair.

[0086]

[0085] In one embodiment, the energy storage component is a capacitor configured to discharge through the primary winding, generating high-voltage stimulus in the secondary winding.

[0087]

[0086] In one embodiment, the control circuit infers the load impedance by analysing the time duration of the voltage decay on the primary side during discharge.

[0088]

[0087] In one embodiment, the control circuit comprises a controller.

[0089]

[0088] In one embodiment, the controller is configured to adapt the energy stored in the energy storage component for a second electrical stimulus based on the inferred load impedance from a previously applied first electrical stimulus.

[0090]

[0089] In one embodiment, the controller is configured to record or send a signal related to the successful or failed applications.

[0091]

[0090] In one embodiment, the controller is configured to record the successful application or failed application to the respective previously applied electrical stimulus.

[0092]

[0091] In one embodiment, the controller measures the voltage decay characteristics via a frequency compensated voltage divider comprised by the control circuit.

[0093]

[0092] In one embodiment, the controller is configured to determine the voltage decay via analogue signals representing the voltages, and further configured to end or record the elapsed time of a digital timer based on a comparison of the analogue signals,

[0094]

[0093] In one embodiment, the controller is configured to start the digital timer based on the triggering of the output transformer.

[0095]

[0094] In a fourth aspect, the invention broadly relates to an electrical stimulus system configured to apply an electrical stimulus to a being, the system comprising: a power source; a capacitor circuit; an output transformer comprising a primary winding and a secondary winding configured to output the electrical stimulus to one or more electrodes; a switching element configured to connect the capacitor circuit to the primary winding; and a controi circuit configured to: (i) control a first electrical stimulus by initiating a discharge of the capacitor circuit through the primary winding via the switching element; (ii) during the discharge, determine a voltage decay characteristic of the capacitor circuit; (ill) determine an operational characteristic of the first electrical stimulus based on the determined voltage decay characteristic; and (iv) generate a control signal for controlling an operational parameter of the system based on the determined operational characteristic.

[0095] In one embodiment, the control circuit determines the voltage decay characteristic by determining an elapsed time for a voltage of the capacitor circuit to fall from a first voltage to a reference voltage.

[0096]

[0096] In one embodiment, the operational parameter of the system comprises a second electrical stimulus.

[0097]

[0097] In one embodiment, the control circuit is configured to apply the second electrical stimulus if the first electrical stimulus was determined to be a failed application.

[0098]

[0098] In one embodiment, the control circuit is configured to apply the second electrical stimulus at a higher voltage than the first electrical stimulus.

[0099]

[0099] In one embodiment, the operational parameter of the system comprises one or more of: the number of capacitors active in the capacitor circuit; a command to temporarily disable further electrical stimulus application; an event logging command; and a command for generating an alert or an alert communication.

[0100]

[0100] In one embodiment, the operational characteristic is related to one or more selected from the group consisting of: the voltage of the one or more electrodes, a measure of success of the electrical stimulus, the load of the one or more electrodes, the resistance of the one or more electrodes, the impedance of the one or more electrodes, a fault of the one or more electrodes, and arcing from the one or more electrodes.

[0101]

[0101] In one embodiment, the first voltage is based on a peak voltage of the capacitor circuit when the discharge is initiated.

[0102]

[0102] In one embodiment, a measurement of the peak voltage is taken at the time of triggering the switching element.

[0103]

[0103] In one embodiment, the control circuit determines the operational characteristic based on the elapsed time being above or below a predetermined reference time.

[0104]

[0104] In one embodiment, an elapsed time below the predetermined reference time corresponds to a successful application of the electrical stimulus, and an elapsed time above the predetermined reference time corresponds to a failed application of the electrical stimulus.

[0105]

[0105] In one embodiment, the predetermined reference time for the successful application is between 3 and 4 microseconds.

[0106]

[0106] In one embodiment, the predetermined reference time for the failed application is selected from the group consisting of: more than 4 microseconds, between 4 and 9 microseconds, and between 6 and 7 microseconds.

[0107]

[0107] In one embodiment, the reference voltage is a predefined proportion of the first voltage.

[0108]

[0108] In one embodiment, the control circuit comprises a voltage measuring device configured to provide a scaled-down voltage representative of the voltage of the capacitor circuit.

[0109]

[0109] In one embodiment, the voltage measuring device comprises a voltage divider.

[0110]

[0110] In one embodiment, the voltage divider is a frequency compensated voltage divider.

[0111]

[0111] In one embodiment, the control circuit comprises a comparator.

[0112]

[0112] In one embodiment, the control circuit comprises a timer module.

[0113]

[0113] In one embodiment, the control circuit comprises an analogue-to-digital converter configured to measure the voltage of the capacitor circuit.

[0114]

[0114] In one embodiment, the control circuit comprises a digital-to-analogue converter.

[0115]

[0115] In one embodiment, the comparator is configured to receive the voltage of the capacitor circuit and the reference voltage and to control a comparator output state.

[0116] In one embodiment, the timer module is configured to determine the elapsed time based, at least in part, on the comparator output state.

[0116]

[0117] In one embodiment, the digital-to-analogue converter is configured to provide the reference voitage to the comparator.

[0117]

[0118] In one embodiment, the control circuit is configured to receive the voltage measured by the analogue-to-digital converter and to control the digital-to-analogue converter based on the received voltage.

[0118]

[0119] In one embodiment, the control circuit is further configured to control stimulus output based on operation of the switching element.

[0119]

[0120] In one embodiment, the control circuit comprises a charge switch operable to control connection of the capacitor circuit with the power source.

[0120]

[0121] In one embodiment, the control circuit is configured to record when a successful application or a failed application occurs.

[0121]

[0122] In one embodiment, the control circuit is configured to adapt one or more operational parameters of the system based on the determined operational characteristic.

[0122]

[0123] In one embodiment, the one or more operational parameters relate to one or more selected from the group consisting of: a capacitance of the capacitor circuit, a length of time between charging and discharging the capacitor circuit, energy stored in the capacitor circuit, and a time until a second electrical stimulus is applied.

[0123]

[0124] In one embodiment, controlling the charging of the capacitor circuit controls the voltage of the electrical stimulus.

[0124]

[0125] In one embodiment, the system comprises a first transformer configured to receive energy from the power source and to step up the voltage of the power source to charge the capacitor circuit.

[0125]

[0126] In one embodiment, the output transformer is configured to step up the voltage to a range between 100V and 20kV.

[0126]

[0127] In one embodiment, the system is integrated into a wearable animal device for delivering the electrical stimulus through the one or more electrodes.

[0127]

[0128] In a fifth aspect, the invention relates to a ’wearable device for a cattie animal, comprising the electrical stimulus system according to any of the preceding embodiments.

[0128]

[0129] In a sixth aspect, the invention broadly relates to a method of inferring a load across an electrode pair on a high voltage side of an output transformer configured to provide an electrical stimulus to a being, the method comprising the steps of: providing an electrical stimulus circuit comprising; a power source; a capacitor circuit connected to the power source and configured to charge to a peak voltage: the output transformer having a primary winding connected to the capacitor and a trigger switch, and a secondary winding configured to output the high voltage electrical stimulus across an electrode pair once triggered by the trigger switch; a controller configured to measure a voltage measurement of the capacitor; and operating the controller to execute the steps of: controlling charging of the capacitor by connection to the power source, initiating discharging of the capacitor by operation of the trigger switch, determining an elapsed time between a voltage of the capacitor falling between a peak voltage and a reference voltage based on the peak voltage, during discharging, and determining a measure of stimulus delivery based on the determined elapsed time.

[0129]

[0130] In one embodiment, the method comprises the step of comparing the elapsed time to a predetermined time threshold to determine the measure of stimulus delivery.

[0131] In one embodiment, the reference voltage is a predetermined voltage based on the peak voltage.

[0130]

[0132] In one embodiment, the reference voltage is a predetermined percent of the peak voltage.

[0131]

[0133] In one embodiment, the reference voltage is determined by an equation based on the peak voltage.

[0132]

[0134] In one embodiment, the reference voltage is chosen to maximise the time difference between ideal open-load and loaded capacitor conditions to get to the same voltage.

[0133]

[0135] In one embodiment, the reference voltage is less than 90% and greater than 10% of the peak voltage.

[0134]

[0136] In one embodiment, the predetermined time threshold is based on experimental or historical data.

[0135]

[0137] In one embodiment, an elapsed time below the predetermined time threshold indicates a successful application of the electrical stimulus to a being, and an elapsed time above the predetermined time threshold indicates a failed application of the electrical stimulus to a being.

[0136]

[0138] In one embodiment, the method comprises the step of the controller controlling the charge of the capacitor.

[0137]

[0139] In one embodiment, the method comprises the step of the controller controlling the trigger switch.

[0138]

[0140] In one embodiment, the method comprises the step of the controller comprising a timer, and the timer controlling the trigger switch when timing starts.

[0139]

[0141] In one embodiment, the control circuit comprises a voltage divider for the controller to take the voltage measurement from.

[0140]

[0142] In one embodiment, the method comprises the step of the controller determining a reference voltage based on the peak voltage through the voltage divider.

[0141]

[0143] In one embodiment, the controller comprises a comparator, and the method includes the step of the comparator comparing an analogue voltage measurement from the voltage divider to an equivalent analogue reference voltage, and outputting a signal when the voltage measurement falls below the reference voltage.

[0142]

[0144] Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

[0143]

[0145] Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

[0144]

[0146] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, a reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0145]

[0147] It is also to be understood that the specific devices illustrated in the attached drawings and described in the following description are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

[0146]

[0148] It is acknowledged that the term “comprise” may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning, allowing for inclusion of not only the listed q components or elements, but also other non-specified components or elements. The terms ‘comprises’ or ’comprised’ or ‘comprising’ have a similar meaning when used in relation to the system or to one or more steps in a method or process.

[0147]

[0149] As used hereinbefore and hereinafter, the term “and / or” means “and” or “or”, or both.

[0148] [150 As used hereinbefore and hereinafter, “(s)” following a noun means the plural and / or singular forms of the noun.

[0149]

[0151] It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present.

[0150]

[0152] When used in the claims and unless stated otherwise, the word ‘for’ is to be interpreted to mean only ‘suitable for’, and not for example, specifically ‘adapted’ or ’configured’ for the purpose that is stated.

[0151]

[0153] For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be chronologically ordered in that sequence, unless there is no other logical manner of interpreting the sequence.

[0152] BRIEF DESCRIPTION OF THE DRAWINGS

[0153]

[0154] Preferred embodiments of the invention will be described by way of example only and with reference to the drawings, in which:

[0154]

[0155] Figure 1: shows a schematic of system 1 according to a first embodiment of the present invention.

[0155]

[0156] Figure 2: shows a schematic of system 2 according to a second embodiment of the present invention, system 1 comprising a first transformer.

[0156]

[0157] Figure 3: shows a schematic of system 2 according to a third embodiment of the present invention, system 1 comprising a first transformer and voltage divider.

[0157]

[0158] Figure 4: shows a schematic of the controller.

[0158]

[0159] Figure 5: shows a table of peak voltage across the capacitor, their respective divided voltages at the analogue-to-digital converter, the associated divided reference voltage at an example 75%, and the experimental results of the time to the reference voltage.

[0159]

[0160] Figure 6: shows a graph representing the times and voltages shown in the table of Figure 5.

[0160]

[0161] Figure 7: shows a representation of an example voltage decay curve for an open and loaded load at 350 volts, as per the data in Figure 5.

[0161]

[0162] Figure 8: shows an example of a collar that utilises the system 1 on an animal.

[0162]

[0163] Figure 9: shows an example voltage decay across the capacitor where an arcing event has occurred across the electrodes, a voltage dip can be seen crossing the reference voltage threshold twice.

[0163]

[0164] Figure 10: shows a circuit of a frequency compensated voltage divider.

[0164] DETAILED DESCRIPTION

[0165]

[0165] With reference to the above drawings, in which similar features are generally indicated by similar numerals, an electrical stimulus system according to a first preferred embodiment of the invention is generally indicated by the numeral (1),

[0166] In brief, the electrical stimulus system (1) is designed to deliver a controlled first electrical stimulus to a being, such as an animal (3) as shown in Figure 8, or person, using a power source (5) delivering electrical energy and connected to a capacitor (4) or capacitor circuit (4) and an output transformer (30) that applies the electrical stimulus across electrode pair (33) when triggered, A control circuit (2) as shown in Figures 1-3 manages the charging of the capacitor (4), measures voltage decay (optionally via a voltage divider (8) shown in Figure 10), and uses fast analogue comparisons to determine the elapsed time it takes for the voltage to drop to a reference level, in one embodiment, 75% of the peak voltage, from the capacitor (4), The elapsed time indicates the measure of success of the first electrical stimulus being applied to a being (10), ranging from a successful application to a being to failed application to a being. A controller (2) is configured to use the elapsed time to adjust operational parameters for future, or a second electrical stimulus accordingly, or to record data of the application of the electrical stimulus,

[0166]

[0167] Compared to the prior art the system (1) references the measurement of load impedance from the low-voltage (primary) side of the output transformer rather than the high-voltage (secondary) side of the transformer as is done in electrical stimulus devices such as electric fence energisers and animal shock collars (100) as shown in Figure 8. This approach addresses the safety, cost, and size challenges associated with traditional high-voltage measurements. Further, an output transformer (30), which provides the voltage to the electrode pair (33) which contact or are proximal to the being (animal or person), is not modified, unlike the prior art. Some prior art discloses adding additional winding on the primary side of the transformer to induce a current to measure. This complexity may add cost to the circuit, size to the circuit components, and may affect the performance of the output transformer. In particular, additional cost is required to add windings to a transformer, it also can be hard to achieve reliability in small transformers due to the isolation space being small. By using the primary side voltages for measurement, the system may utilise smaller, cost-effective components, making it efficient and suitable for applications like wearable animal devices,

[0167]

[0168] The electrical stimulus system (1 ) is configured to apply an electrical stimulus to a being (10). The being may be an animal or person. For example, the electrical stimulus system may be used in an electric fence system, or in a wearable device 100 attached to an animal 3 or person. Herein all operational characteristics will relate to small volume, lightweight, shock collar (100) to be used on a large cattle animal (3) as the particular numbers used herein, such as voltage, reference voltage, and elapsed time relate to the specific application of the electrical stimulus system (1) and the circuit design and configuration. However, a skilled person in the art will be able to adjust the operational parameters to suit their specific application.

[0168]

[0169] The electrical stimulus system (1 ) comprises a power source (5). The power source may be supplied power from mains lines or similar, solar, may be a battery 5, or any combination of sources. The circuits shown in the Figures are exemplary and would require changes based on the power source selected, such as for use with mains power as would be appreciated by those skilled in the art. In one embodiment, where the system is used for a lightweight wearable device, the battery (5) may supply 4 volts. Preferably the battery' (5) is charged by solar power. The battery (5) may be low weight, and preferably also low volume (e.g. good specific energy density) to be carried by the wearable device and hence the animal.

[0169]

[0170] The power source (5) is connected to an energy storage component (4). In one embodiment, the energy storage component is a capacitor (4). In other embodiments, the energy storage component is a capacitor circuit (4) comprising one or more capacitors. The capacitor stores energy / voltage from the power source (5) and is responsible for storing energy from the power source and supplying the energy required for a voltage pulse to be sent to the output transformer 30 as shown in Figures 1 -3.

[0170]

[0171] Capacitors can reduce the near instantaneous high current demands on power sources by storing and supplying energy that might otherwise cause the voltage from the power source (5) to sag and in some instances, the power source to be damaged. In a preferred embodiment, there is only one capacitor (4) in the circuit, as shown in Figures 1 -3. In embodiments not shown the capacitor (4) comprises a capacitor circuit with one or more capacitors configured to store energy from power source (5).

[0171]

[0172] The capacitor (4) stores energy supplied by the power source (5) and is linked to an output transformer (30). The output transformer (30) comprises a primary' winding (31) connected to both the capacitor (4) and a trigger switch (6), and a secondary winding (32) configured to output the electrical stimulus across an electrode pair (33) once the trigger switch (6) is activated in operation. The control circuit or controller may be configured to trigger the trigger switch (6), or the trigger switch may be triggered by an external source. Where an electric fence is concerned, the trigger switch may be connected to a timer module to periodically trigger the electrical stimulus.

[0172]

[0173] In one embodiment, the output transformer (30) for a wearable device has a turns ratio of 1:15. The voltage output by the output transformer is between 100 volts and 20 kilovolts, preferably to 18kV. Determining Reference Voltage

[0173]

[0174] The system (1) comprises a control circuit (2) to at least measure the voltage across the output transformer (30), and optionally to manage various operational aspects of the system (1).

[0174]

[0175] The term control circuit (2) is broadly used to describe the functions of one or more processing apparatus such as microprocessors and supporting electronics. A controller may be a single processor, or a combination of multipie processing devices as may be practical. A controller will typically feature output pins which are operably connected to switching devices to control the state of that switching device, and ADC pins which are configured for measuring voltages. For example, the pin of a microprocessor may be connected to operate the gate of a MOSFET switching device. In some embodiments, the control circuit is implemented by a microprocessor device and may optionally include supporting hardware to facilitate the desired functionality of the device such as gate drive electronics and voltage sampling electronics.

[0175]

[0176] In one embodiment the control circuit (2) is configured to measure the voltage of the capacitor (4), and output the elapsed time from the triggering of the output transformer (30) to the time it takes for the voltage measurement to drop to a predefined percent of the peak voltage of the capacitor (4) as the capacitor discharges through the output transformer. The peak voltage is subject to change based on the charge rate of the capacitor, which is subject to other factors related to the power source such as current supply rating, states of charge and the like, or may be controlled to a particular voltage level to thereby provide control over the strength of any output pulse. Reference to a ‘peak voltage’ is intended to describe the charge of the capacitor, however due to capacitor characteristics that charge may decrease over time, the peak voltage is the voltage at the time of triggering of the trigger switch (6).

[0176]

[0177] In some embodiments, the system (1) may be designed without a microprocessor-based control circuit (2), for example, a control circuit relying solely on components such as the analogue-to-digital converter (12), digital-to-analogue converter (11), and the timer module (10) to perform operations. Conversely, the system (1) may comprise a controller (2) that performs functions without the need for separate analogue-to-digital converter (12), digital-to-analogue converter (11), and timer module (10) components. In this setup, the controller (2) integrates these functionalities internally, handling voltage measurements, setting reference voltages, and recording elapsed times through its own processing capabilities. The controller (2) may include built-in analogue-to-digital conversion and timing functions, allowing it to directly process the voltage measurements and perform comparisons using software algorithms. This integration can streamline the system design and potentially enhance performance by centralising control within a single component. Herein, reference to controller and control circuit are exchangeable where applicable. The term controller is used primarily henceforth for ease of description.

[0177]

[0178] The timer module may be implemented by any combination of hardware and / or software and is referred to in this specification as a timer. The timer will typically have one or more triggers which are operable to control the start and stop of a time recording and thereby control the measurement of an elapsed time. In one example, the timer is integrated within a microprocessor as may be used for implementing functions of the controller.

[0178]

[0179] Described herein is an exemplary embodiment where the controller comprises components such as the analogue-to-digital converter (12), digital-to-analogue converter (11), and timer (10) to perform operations. The controller (2) in one embodiment is further configured to operate other parts of the system (1) such as the operation of the circuit via an on / off switch, charging of the capacitor, triggering the output transformer, etc.

[0179]

[0180] The controller comprises a memory component (16), which may be random-access memory, or a non-volatile memory such as flash memory or EEPROM, integrated within the controller (2). This memory component (16) stores data related to the operational characteristics of the system (1), such as the peak voltage (divided / and or actual), associated reference voltages (divided / and or actual), occurrence of successful or failed application, the association of successful or failed application with application of electrical stimulus, the time stamp and location of the electrical stimulus, the elapsed times recorded, and any adjustments made to the operational parameters. By recording this data, the controller (2) can perform diagnostics, adapt applied electrical stimulus, and maintain a history of events for analysis or similar.

[0180]

[0181] The controller (2) is configured to determine or receive a peak voltage - an example peak voltage and corresponding voltage decay curve is shown in Figure 6. The controller (2) is configured to receive a voltage measurement from the control circuit (2), or it may determine the peak voltage by determining how long the capacitor (4) was charged for, or by referencing previously stored data relating to the peak voltage. The peak voltage in some embodiments may not change, and thus the reference voltage is always the same. This may be the case for an electric fence energiser. However, in one embodiment, the peak voltage is adjustable. Upon determining the peak voltage, the control circuit (2) is configured to determine a reference voltage, which is a proportion, preferably 75% in one particular use case, of the peak voltage. The selection of 75% as the reference voltage is based on experimental data obtained by conducting tests across a range of voltages. These experiments involve determining the operational fastest and slowest voltage decays for both successful loads (e.g., when an animal is present across the electrode pair (33)) and failed application (e.g., an open load 'where no being is present across the electrode pair (33)). By analysing the time it takes for the voltage to decay to various percentages of the peak voltage, it was found that using 75% provides the greatest time difference between successful or failed applications, enhancing the system’s ability to accurately differentiate between them.

[0181] Equation Relationship

[0182]

[0182] In some embodiments, the reference voltage is calculated using an equation that depends on the peak voltage of the capacitor (4). This method allows for a more precise determination of the reference voltage, tailored to the specific characteristics of the system at different operating voltages. For example, experimental data may indicate that the optimal reference voltage, which maximises the time difference between loaded and open-load conditions, does not remain a constant proportion of the peak voltage across all levels. Instead, it may vary in a manner that can be represented by a mathematical equation derived from the experimental results.

[0183]

[0183] Figure 7 illustrates a graph where the average elapsed time between the open-load and loaded conditions is plotted against different peak voltages. Note that the voltage data at 400 volts is likely an error in reading. A linear equation can be fitted to this data, suggesting that the optimal reference voltage varies linearly with the peak voltage. This linear relationship can be expressed as: Vref=mxVpeak+b. Where Vref is the reference voltage, Vpeak is the peak voltage of the capacitor, and m and b are constants determined from the experimental data.

[0184]

[0184] By employing this equation, the controller (2) is configured to calculate the reference voltage for any given peak voltage, ensuring that the system operates optimally across a range of voltages. This approach enhances the system's ability to accurately differentiate between loaded and open-load conditions based on the elapsed time measurements.

[0185]

[0185] Alternatively, the relationship between the reference voltage and the peak voltage may be non¬ linear. For instance, the experimental data might fit better to a quadratic or exponential equation. By incorporating equations, whether linear or non-linear, or lookup tables based on experimental data, the system (1) ensures that the reference voltage is always set to a value that maximises the time difference between loaded and open-load conditions. This optimisation improves the accuracy of load detection and the overall effectiveness of the electrical stimulus delivery.

[0186] Reference Voltage

[0187]

[0186] In various embodiments of the system (1), the reference voltage used by the control circuit (2) to determine when to measure the voltage decay can vary across a range of percentages of the peak voltage of the capacitor (4). 75% of the peak voltage is a preferred reference point due in at least one specific use case determined in experimental findings indicating it provides a significant time difference between load-present and no-load conditions. As such, the reference voltage percentage is not limited to this value. The system (1) may utilise reference voltages ranging from as low as 10% to as high as 90% of the peak voltage, depending on specific operational requirements.

[0188]

[0187] As measurements of the voltage decay approach 10% of the peak voltage, the time required for the capacitor voltage to decay to this level increases, resulting in a longer measurement window. This extended duration allows for less stringent requirements on timing accuracy, as small inaccuracies in timing have a reduced impact over a longer time span. However, the prolonged decay period may introduce increased errors due to anomalies or irregularities in the voltage decay curve. Consequently, ‘while the timing accuracy requirements are relaxed, the potential for measurement errors increases as the reference voltage approaches 10% of the peak voltage. In one embodiment, due to the saturation of the transformer, the longer time periods are measuring longer amounts of time the transformer is in the unsaturated region, the unsaturated region tends to have similar voltages at similar times (i.e. the curves offer similar information to each other), regardless of the load, hence there is less benefit of a lower reference voltage, as the information captured is the same between the two conditions,

[0189]

[0188] Conversely, as the reference voltage approaches 90% of the peak voltage, the time for the voltage to decay to this level after discharge initiation is significantly shorter. This necessitates higher timing resolution and accuracy, as even minor timing inaccuracies can substantially affect the proportional error in the elapsed time measurement. The stringent timing requirements demand precise and fast-responding measurement equipment to capture the rapid voltage decay accurately. This can lead to reduced errors in measurement and a more accurate determination of the operational characteristics across the electrode pair. However, measuring at a higher reference voltage reduces the influence of the transformer in the unsaturated region. Therefore, while the requirements for accurate timing are increased as the reference voltage tends towards 90% of the peak voltage, the potential for errors due to recording voltage levels at unsaturated levels are decreased.

[0190]

[0189] Different output transformers may require the reference voltage to be optimised based on their specific characteristics. In one embodiment, setting the reference voltage at 75% of the peak voltage provides a good measurement when the output transformer operates within its non-saturated range. Selecting an appropriate reference voltage ensures that the elapsed time measured corresponds significantly to the period during which the output transformer remains unsaturated. By optimising the reference voltage to increase the elapsed time, the system can capture a greater portion of the voltage decay associated with the transformer's operation in the unsaturated zone, thereby enhancing measurement accuracy.

[0191]

[0190] In one embodiment, the reference voltage is chosen to maximise the time difference between ideal open-load and loaded electrode conditions to get to the same voltage. The voltage at which the time difference is greatest is a good option for the reference voltage. A greater time difference will allow for more accurate determination of the elapsed time. A skilled person in the art will be able to optimise the accuracy for different operating conditions and applications. In some embodiments, the reference voltage may be the 0% of the peak voltage ■■ where the timer measures the time until complete voltage decay is reached. If the correct conditions allow, accurate timing differentials are able to be achieved. As reference voltages tend towards 0 and 100 percent, it may be more difficult to determine timing differentials.

[0192]

[0191] A table and associated graph shown in Figures 5 and 6 show various times it takes to go from various peak voltages to 75% of the peak voltage for open load (no being present) and 400 ohm resistance (being present / successful application). 400 ohm in this particular use case was found to be a useful resistance which simulated a catle animal for the specific circuit. A skilled person in the art will be able to apply this experimental analysis to their specific circuit and application to find an appropriate reference voltage which yields the largest difference between successful or failed application across their range of voltages. Figure 7 shows an example voltage decay curve for a load and no load condition for the data referenced in figure 5, at 350 volts.

[0193]

[0192] In one embodiment, an analogue-to-digital converter (12) measures the voltage after the capacitor (4), and sends the output voltage to the controller (2) to determine the peak voltage.

[0194] Alternatively, the peak voltage is determined prior by a selection by the controller or user.

[0195]

[0193] Where the peak voltage is dynamic, the controller (2) may utilise a lookup table or similar mechanism to correlate an experimentally found ideal reference voltage for each specific peak voltage. During experimentation, various peak voltages are tested, and for each, the reference voltage that provides the largest time difference between successful or failed application is identified. By storing these ideal reference voltages corresponding to different peak voltages in the lookup table or similar, the controller (2) can select the optimal reference voltage for the current peak voltage. This enhances the systems ability to accurately differentiate between successful or failed stimulus application based on the elapsed time measurements derived from the different peak voltages since each has a respective unique reference voltage.

[0196]

[0194] In the present application described, 75% of the peak voltage was found to be useful across all peak voltage ranges with circuit components used. It may be necessary to characterise and calibrate the timing and voltage decay characteristics forth© specific application (e.g., an animal shock collar) and the particular printed circuit board (PCB) design. Variations in components and layout can affect the measurements, so device-specific calibration ensures accuracy.

[0197] Electrodes

[0198]

[0195] In the exemplary embodiments described in this specification, two electrodes are illustrated and are typically polarised as a positive and a negative terminal so as to establish an electrical potential difference between them during operation. In a standard configuration, the negative electrode is electrically coupled to the local system ground, while the positive electrode is driven by the output of the transformer (30).

[0199]

[0196] In the exemplary embodiments depicted in the figures, the system delivers the electrical stimulus via an electrode pair (33). In this configuration, a first electrode is connected to the high-voltage output of the secondary winding (32) of the output transformer (30), and a second electrode provides the return path, and is typically connected to the system local ground. A potential difference is thus established directly between these two electrodes, resulting in a controlled current path through the tissue located between the electrodes.

[0200]

[0197] Accordingly, the stimulus energy generated by the transformer is delivered across the potential formed between the electrode pair. It should be appreciated, however, that references in this specification to “an electrode pair” are not intended to be limiting and are made in reference to the example depicted. The invention is compatible with a wide variety of electrode numbers and configurations. For example, in certain embodiments a single active (i.e., non-grounded) electrode may be employed, with the return path for the delivered energy provided by any available local ground or earth reference, such as the animal’s body in contact with a grounded conductive element of the collar assembly.

[0201]

[0198] In other embodiments, multiple active electrodes may be provided and driven either simultaneously or in a time-multiplexed sequence. These may share a common ground electrode or may be arranged in multiple active-return groupings to create a plurality of selectable or adaptive current paths. Such arrangements can be used to shape the electric field distribution, alter the perceived stimulus, enhance fault tolerance, or reduce skin impedance effects by allowing the system to dynamically choose the most effective electrode pair based on sensed conditions.

[0202]

[0199] Further alternative configurations include multi-point arrays, in which several electrodes are arranged around the collar for directional control of stimulus delivery; asymmetrical electrode geometries, where electrode size or spacing is varied to influence current density; and floating or isolated electrodes, which are capacitively or inductively coupled to the output stage to reduce direct conduction while still delivering a stimulus waveform.

[0203]

[0200] Accordingly, references to two electrodes or a “pair” of electrodes in the examples should be interpreted as including any number of electrodes arranged so as to define at least one conductive or capacitive path suitable for delivering the output energy described herein. Further, the term "one or more electrodes" as used herein and in the claims refers to the physical terminals or conductive surfaces provided by the system for delivering the stimulus, wherein at least one such electrode is present and is configured to complete an electrical circuit through a target being via a corresponding return path, irrespective of whether said return path is another electrode integrated into the system or an external ground potential.

[0204] Peak and Divided Voltages

[0201] The peak voltage in the system (1) refers to the voltage to which the capacitor (4) is charged before it is discharged through the output transformer (30). This peak voltage is proportional to the energy of the electrical stimulus delivered to the being via the electrodes (33). The peak voltage may be set by the user, allowing customisation of the stimulus intensity according to specific needs or preferences. Alternatively, the controller (2) is configured to set or adjust the peak voltage based on previous inferred load conditions recorded by the controller (2). For instance, if the system detects that previous stimuli were less effective due to higher load impedance (longer elapsed times), the controller (2) may increase the peak voltage for subsequent stimuli to enhance the stimulus effectiveness.

[0205]

[0202] Note that the peak voltage of the capacitor (4) or the output from the first transformer (9) is less than the output voltage from the output transformer (30). The output transformer (30) has a high turns ratio, over 10, 15, or 20 in some embodiments, which steps up the voltage from the capacitor (4) to a much higher level suitable for delivering the electrical stimulus across the electrode pair (33). For instance, with a peak voltage of 500 volts and an output transformer turns ratio of 1:20, the voltage output by the output transformer (30) would be approximately 10,000 volts.

[0206]

[0203] The peak voltage is the highest voltage measured by the voltage measuring device (8) during the charging phase of the capacitor (4). In the embodiment where the voltage measuring device (8) includes a voltage divider (described later), the actual voltage measured is a scaled-down version of the true voltage across the capacitor (4). The controller (2) is configured to know the scaling factor applied by the voltage divider. For example, if the voltage divider reduces the voltage by a factor of 100, a measured voltage of 5 volts corresponds to an actual voltage of 500 volts across the capacitor (4). The controller (2) uses this information to accurately determine the peak voltage and, consequently, calculates the corresponding divided reference voltage for precise comparisons during discharge.

[0207] Current

[0208]

[0204] The voltage divider (8) is designed to divide down the high voltage across the capacitor (4) to a safe, low-voltage level suitable for the controller (2) and its associated components, such as the analogue-to-digital converter (12). In contrast, prior art systems that measure current directly face significant challenges due to the high currents involved. The prior art does not present a convenient way to reduce current without inaccuracies, or risk to the circuit.

[0209] Trigger

[0210]

[0205] In one embodiment, the controller is configured to switch the charge switch 7 to charge the capacitor 4, optionally via a first transformer (9). The charge switch 7 electrically connects and disconnects the power source to the capacitor to affect charging of the capacitor. An alternative to the capacitor (4) being connected and disconnected from the power source (5) to charge it is to have the capacitor consistently connected to the power source (5) such that it remains in a state of charge for most of the time. The charge rate may be controlled, for instance, by a constant current source or a resistor such that the current between the power source and capacitor is limited and the power source is somewhat isolated from operation of the output transformer, 'which may be detrimental to the longevity of the power source due to the high instantaneous current demands and impact that may have on some battery technologies. However, it is preferable in most instances for the connection of the capacitor to the power source to be operated by the control circuitry.

[0211]

[0206] The controller is further configured to trigger the trigger switch (6) to discharge the capacitor (4) through the output transformer (30) to apply an electrical stimulus across the electrode pair (33).

[0212]

[0207] The electrode pair (33) in the system (1) can be configured in various forms to suit different applications. In an electric fence energiser, the electrodes (33) may be integrated into the fence system, enabling the delivery of electrical stimuli along the fence line to deter animals or unauthorised intrusions. For wearable animal devices like collars, the electrodes (33) can be probes that protrude from the collar to make direct contact, or are proximal, with the animal's skin, or flat probes that lay against or are proximal to the animal’s coat, ensuring effective transmission of the electrical stimulus. Alternatively, the electrodes (33) may be made of woven conductive strands or threads embedded within the collar material, providing a less intrusive and more comfortable contact method.

[0213]

[0208] In some embodiments, the controi circuit (2) is configured to coordinate the triggering of the electrical stimulus delivery, and charge the capacitor (4). However in other embodiments a separate controi circuit may be used for charging the capacitor.

[0214]

[0209] The control circuit operates the trigger switch (6) to discharge the capacitor through the output transformer and thereby deliver the electrical stimuli. In some embodiments, the control circuit is configured to record an elapsed time beginning when the trigger switch is operated. For example, at the exact moment the trigger switch (6) is engaged, the controller (2) simultaneously starts the timer module (10). This precise synchronisation ensures that the timing measurement begins at the initiation of the electrical stimulus discharge. By starting the timer (10) as soon as it triggers the trigger switch (6), the controller (2) can accurately record the elapsed time it takes for the voltage across the capacitor (4) to decay to the reference voltage level. Timing accuracy is determinative of accuracy, and therefore for determining the measure of success of the electrical stimulus as the elapsed time is very small. The timing of the start of the discharge and the start of the timer should be as close together as practical.

[0215]

[0210] In one embodiment, the control circuit (2) includes a timer module (10) configured to measure the elapsed time for the voltage of the capacitor (4) to drop from a first voltage level to a predetermined reference voltage. To achieve this, the control circuit (2) further comprises a comparator module (13) that receives both the capacitor voltage and the reference voltage. As the capacitor voltage decays and crosses the reference level, the comparator module (13) changes its output state. The timer module (10) determines the elapsed time at least in part based on this change in the comparator’s output state. Additionally, the control circuit (2) comprises an analogue-to-digital converter (12) to measure the capacitor voltage and a digital-to-analogue converter (11) to provide the reference voltage to the comparator module (13). By utilising the analogue-to-digital converter (12) readings, the controller (2) can adjust the digital-to-analogue converter (11) output to set an appropriate reference voltage derived from the actual capacitor voltage.

[0216] Comparator

[0217]

[0211] The control circuit comprises a voltage measurement of the capacitor (4) The voltage measurement is received by the analogue-to-digital converter (12), and the scalar output of the analogue-to-digital converter (12) is sent to controller (2). The controller (2) is configured to determine the reference voltage, and send a signal representation of the reference voltage to the digital-to-analogue converter (11). The digital-to-analogue converter (11) in turns outputs a voltage representing said signal to the comparator (13).

[0218]

[0212] The comparator (13) is configured to receive the reference voltage from the digital-to-analogue converter (11) and provide a comparison output indicating whether the voltage measurement is above or below1the reference voltage. Specifically, the comparator (13) receives two analogue input signals: one from the voltage measurement device (8), which provides a scaled-down voltage representative of the voltage across the capacitor (4), and the other from the digital-to-analogue converter (11), which outputs the reference voltage related to the peak voltage based on a signal from the controller (2).

[0213] When the capacitor (4) begins to discharge after the trigger switch (6) is activated, the voltage across it starts to decrease. The comparator (13) continuously compares the real-time voltage measurement from the voltage measurement (8) to the reference voltage. If the voltage measurement is above the reference voltage, the comparator (13) outputs a specific logic level (e.g., high). As the voltage measurement decreases and reaches the reference voltage level, the comparator's output switches to the opposite logic level (e.g., low).

[0219]

[0214] Comparison by the comparator is performed using analogue signals, which may allow for faster operation than digital comparisons, or at least require less processing power, compared to digital methods. However, digital methods may be implemented, for example, by using interrupts for precise timing measurements where regular ADC sampling frequencies are not fast enough to capture the transient voltage with sufficient resolution.

[0220]

[0215] In one exemplary / embodiment, the comparator is a hardware block within the integrated circuit of a microprocessing device. For example, many STM Fx based processors have an integrated comparator which is internally configured to start or stop a timer when the comparator state changes. Embodiments discussed herein refer to such an implementation. In another exemplary embodiment, the comparator is a device external to the processor and has an output connected to a GPIO pin of a microprocessor, where the microprocessor is configured to stop a timer based on the pin state changing as controlled by the external comparator. In such instances, an interrupt is often the most accurate implementation of timing a change of pin state. Those skilled in the art will appreciate that there are many other circuit configurations which enable measurement of a timing event and the scope of this invention is not intended to be limited to the particular way a timing event is evaluated.

[0221] E / apsed Time

[0222]

[0216] The timer (10) or controller (2) is configured to receive the comparison output from the comparator (13) and record the elapsed time it takes for the voltage measurement to decrease to the reference voltage from the time the trigger switch (6) is triggered. The timer (10) starts counting when the controller (2) activates the trigger switch (6), ensuring accurate measurement of the elapsed time. The elapsed time may be stored in the memory component (16).

[0223]

[0217] The elapsed time is indicative of the measure of success of the applied electrical stimulus. In one embodiment, instead of a binary successful or failed application, the system can interpret the elapsed time as a continuum of successful application. Shorter elapsed times may indicate a more successful application of energy transfer to the being, suggesting good contact and appropriate impedance, while longer elapsed times may indicate less successful energy transfer to the being, possibly due to poor contact or higher impedance. The controller may also be configured to merely output a binary successful or failed application based on the elapsed time and a comparison with an experimentally found predetermined reference time.

[0224]

[0218] In one embodiment, if the elapsed time threshold is above four microseconds, it can generally be assumed that electrical stimulus application was a failed application.

[0225]

[0219] Based on the recorded elapsed time when the reference voltage is met, the controller is configured to derive or infer one or more operational characteristics across the electrode pair (33). These characteristics may relate to the impedance of the load or voltage of the electrical stimulus across the electrode pair (33) or the measure of success of the applied electrical stimulus to the being. The controller (2) is configured to control the voltage of the electrical stimulus dependent on these operational characteristics, adjusting parameters such as the peak voltage to which the capacitor (4) is charged.

[0220] !n one embodiment, the operational characteristics relate to factors selected from voltage, load, resistance, and impedance. The derivation of these characteristics may be based on the elapsed time, on some embodiments, whether the elapsed time is above or below a predetermined reference time. An elapsed time below the predetermined reference time corresponds to a successful application indicating a being is present at the electrode pair (33) to receive the electrical stimulus. Conversely, an elapsed time above the predetermined reference time indicates a failed application where no being is present. However, by considering the actual value of the elapsed time, the system can assess varying measures of success, enabling more nuanced control and feedback. The predetermined reference time value is determined from experimental evaluation of the circuit during delivery of an electrical stimulus, across successful or failed applications, as well as any other conditions that may be desired to be determined. I

[0221] Figure 9 illustrates an example of voltage decay across the capacitor (4) where an arcing event has occurred across the electrode pair (33). An arcing event refers to an unintended electrical discharge that occurs when electricity jumps across a gap between conductors, in this case, the electrodes, or in other cases, within the circuitry or components, or across to a being, or vegetation touching or proximal an electric fence. Arcing can impact the voltage decay characteristics observed during the discharge of the capacitor, as well as negatively affect the performance of the system or components.

[0226]

[0222] In a typical discharge without arcing, the voltage across the capacitor decays smoothly and predictably, crossing the reference voltage threshold only once. However, when an arcing event occurs, the voltage decay curve exhibits irregularities due to rapid fluctuations in the discharge path's impedance. Specifically, a voltage dip can be observed, causing the voltage to cross the reference voltage threshold multiple times in some embodiments. This results from the transient nature of the arcing, where the arc may ignite and extinguish rapidly, altering the effective load impedance seen by the system. There are often a plurality of voltage dips which occur at different voltages.

[0227]

[0223] When the control circuit (2) measures the voltage decay and detects that the voltage crosses the reference voltage threshold more than once, it can infer that an arcing event is occurring.

[0228]

[0224] In other embodiments, the controller (2) is configured to determine arcing events without utilising the reference voltage. Instead, the controller continuously measures the voltage across the capacitor (4) during the voltage decay phase and monitors for irregular voltage fluctuations. The controller is configured to detect when the voltage is measured multiple times at certain levels during the decay process. These repeated measurements or crossings of the same voltage levels indicate instability in the voltage decay curve, which is characteristic of arcing events. By analysing the occurrence of these multiple voltage measurements, the controller can identify potential arcing events at the electrode pair (33). This method allows the controller to determine arcing based on the overall behaviour of the voltage decay rather than relying on a specific reference voltage threshold. Upon detecting such irregularities, the controller can respond appropriately by adjusting operational parameters, recording the event for diagnostic purposes, or triggering safety mechanisms to mitigate the effects of the arcing.

[0229]

[0225] The controller is configured to detect an arcing event and adjust operational parameters accordingly. In one embodiment, the controller is configured to reduce the peak voltage of a second electrical stimulus to minimise the likelihood of arcing in subsequent stimuli or modify the timing or waveform of the electrical stimulus to mitigate arcing conditions. In further embodiments, the controller is configured to log arcing events in its memory component for diagnostic purposes. In one embodiment, the controller is configured to trigger safety mechanisms, such as temporarily disabling further electrical stimulus application until the issue is resolved, and can alert the user or operator through indicators or communication interfaces.

[0226] To accurately differentiate between time intervals that differ by as little as 4 microseconds, the system (1) may employ a timing mechanism with sufficient resolution and precision. In one embodiment, the timer (10) is a digital timer. In one embodiment, the timer (10) operates at 16 MHz offering a time resolution of 62.5 nanoseconds (1 / 16 MHz).

[0230]

[0227] The system (1) utilises voltage decay measurements to infer the load impedance across the secondary winding (32) of the output transformer (30). This inference is used for determining whether an electrical stimulus has been successfully delivered to a being, such as an animal in contact with the electrodes (33), or if there is a no-load condition indicating no contact,

[0231]

[0228] When the capacitor (4) discharges through the primary winding (31) of the output transformer (30), the voltage across the capacitor begins to decay. The rate of this voltage decay is influenced by the overall impedance in the discharge path, which includes the reflected impedance from the secondary side of the transformer. By analysing the characteristics of this voltage decay, the system can infer the load conditions on the secondary winding (32).

[0232]

[0229] When the electrodes (33) are in contact with a being, such as an animal, the load impedance on the secondary winding (32) decreases significantly. The presence of the being introduces a conductive path that allows current to flow more readily, effectively lowering the impedance. This reduced impedance is reflected back to the primary winding (31) as a lower impedance. As a result, the overall impedance in the discharge path of the capacitor (4) decreases, allowing the capacitor to discharge more quickly. The energy stored in the capacitor is released over a shorter period due to the higher current flow through the load. The timer (10), which starts simultaneously when the controller (2) triggers the trigger switch (6), records a shorter elapsed time for the voltage to decay to the reference voltage level because of the faster decay rate. By detecting this shorter time interval, the controller (2) infers that a significant load is present on the secondary side, indicating successful contact with the being and effective delivery of the electrical stimulus. Example times for an open load (being not present) and a 400 ohm load (being present) are shown in the table of figure 5. Wherein a 400 ohm resistance is used to simulate a cattle animal being present across the electrodes (33).

[0233]

[0230] In the absence of a being, for example, when the electrodes (33) are not in contact with an animal, the impedance seen by the secondary winding is very high, effectively an open circuit. This high impedance is reflected back to the primary winding (31) as a high impedance. With a higher overall impedance in the discharge path, the energy stored in the capacitor (4) is released more slowly, resulting in a slower voltage decay across the capacitor. The lack of a conductive path means less current flows, prolonging the discharge process. The timer (10) measures a longer elapsed time for the voltage to decay to the reference voltage due to the slower decay rate. By detecting this longer time interval, the controller (2) determines that there is little to no load present on the secondary side, indicating that the electrical stimulus was not delivered to a being, or the application of the electrical stimulus was less successful.

[0234] Outputs

[0235]

[0231] By measuring the elapsed time for the voltage to decay to the reference level, the system (1) can determine the measure of success of the electrical stimulus delivery.. Shorter times indicate lower impedance and better electrical stimulus application success, and longer times indicate higher impedance and worse electrical stimulus success.

[0236]

[0232] The measure of success in the context of the electrical stimulus system refers to how effectively the electrical pulse is delivered to the being, as inferred from the elapsed time recorded by the controller (2) when the voltage across the capacitor (4) decays to the reference voltage. The controller is configured to interpret this measure in various forms, providing valuable feedback for adjusting the system's operational parameters. It may use the actual elapsed time as a scalar output, where a shorter elapsed time indicates a successful pulse delivery due to lower impedance (load-present condition), and a longer elapsed time suggests a less successful delivery. The controller may map the elapsed time to a success score on a predefined scale or estimate the load impedance based on the elapsed time, serving as a scalar measure of success. It can categorise the success into levels such as 'Excellent,' 'Good,' 'Fair,' and 'Poor,' corresponding to specific ranges of elapsed times. The controller is configured to adjust operational parameters based on the measure of success, such as modifying the peak voltage, pulse duration, or frequency to optimise future pulse deliveries. It may also apply additional stimuli or increase the voltage incrementally until a successful measure is achieved. The controller can provide visual or audible feedback to the user, display real-time success measures, and record data for trend monitoring and statistical analysis.

[0237]

[0233] The controller (2) is configured to the elapse time to adjust operational parameters, such as modifying the peak voltage for subsequent electrical stimuli if a lower impedance is detected, to enhance the likelihood of effective stimulus. This is because an increased voltage may be more likely to jump across an air gap from the electrodes to the being, to therefore make a more successful application of stimulus. In one embodiment, the controller is configured to increase the voltage after one or more failed electrical stimulus applications. In one embodiment, the controller is configured to increase the voltage of a second electrical stimulus applied after one or more electrical stimulus applications that are less successful than a recorded first electrical stimulus application.

[0238] Dynamic voltage adjustment

[0239]

[0234] The system (1) incorporates safety mechanisms to ensure that high voltages and unsafe operating conditions are prevented, in compliance with regulatory standards. High shock voltages can occur in high-impedance circuits, such as when there is no load or when the electrodes (33) are not in contact with a being. In these situations, the absence of a conductive path causes the voltage across the output transformer (30) and the electrodes (33) to rise to higher levels, potentially exceeding safe limits prescribed by regulations.

[0240]

[0235] To mitigate this risk, the controller (2) is configured to monitor the number of consecutive failed or low success electrical stimulus applications, A failed application is identified when the elapsed time recorded by the timer (10) exceeds a predetermined reference time value, indicating a slower voltage decay due to the high impedance. If the controller (2) detects that the number of failed or low success for a first electrical stimulus surpasses a predefined threshold, set according to regulatory requirements or specified by the user, the system automatically reduces the peak voltage to which the capacitor (4) is charged for a subsequent second electrical stimulus.

[0241]

[0236] By lowering the peak voltage, the system decreases the maximum voltage output by the output transformer (30), thereby reducing the shock voltage delivered across the electrodes (33). This adjustment helps prevent the production of excessively high voltages that could pose safety hazards. The threshold number of allowable failed or low success electrical stimulus applications before voltage reduction is implemented can be defined based on safety regulations governing electrical stimulus devices or set by the user to adhere to specific safety protocols.

[0242]

[0237] In practice, if the controller (2) records a series of failed or low success electrical stimulus applications exceeding the threshold, for example, three consecutive instances, it interprets this as a persistent high-impedance situation. The controller (2) then reduces the peak voltage incrementally or to a predetermined safe level for a subsequent second electrical stimulus. This ensures that even if the high-impedance condition continues, the voltage levels remain within safe operating limits.

[0243]

[0238] By incorporating this dynamic voltage adjustment based on monitored conditions, the system (1) ensures compliance with safety regulations that limit the maximum allowable voltages and energy levels for electrical stimuli. It protects against the risks associated with high-voltage shocks in open-circuit scenarios, enhancing the safety and reliability of the device. This feature may be useful in applications like electric fence energisers and wearable animal devices, where varying environmental factors and user interactions can lead to changes in circuit impedance.

[0244] Adjusting Capacitor Charging

[0245]

[0239] Depending on the one or more operational characteristics, the controller (2) is configured to adjust operational parameters such as; the number of capacitors active in the capacitor circuit (4); the number of electrical stimuli delivered; the length of time between charging and discharging the capacitor (4); and the energy stored in the capacitor (4) and hence peak voltage. The controller (2) may also be configured to determine variables of the voltage pulse, allowing it to control changes to the voltage amplitude, current amplitude, period, frequency of the voltage pulse, and the number of electrical stimuli within a duration of an electrical stimulus. Wherein the voltage pulse is the pulse leaving the capacitor.

[0246]

[0240] In a further embodiment, the controller (2) is configured for controlling the charge of the capacitor (4) by regulating the energy flow from the power source (5). It receives a voltage measurement from between the capacitor (4) and the primary winding (31) through a voltage measurement device (8), which may include a voltage divider. This allows the system to determine the peak voltage of the capacitor (4) once it is fully charged.

[0247]

[0241] In one embodiment, to control and adapt the output energy (voltage and / or current), the controller is configured to adjust the voltage to which the capacitor is charged. This is achieved using the digital-to-analogue converter to set the desired charge voltage level. The comparator (13) monitors the voltage across the capacitor and compares it to the set voltage from the digital-to-analogue converter. Once the capacitor reaches the desired voltage, the comparator (13) is configured to signal the controller to stop charging by opening the charging switch, effectively breaking the charging circuit. Where a first transformer is used the charging switch operates very rapidly to accommodate the alternating current (AC) nature of the first transformer and to ensure precise control over the charging process. By using the same hardware for both measuring the voltage decay and controlling the charge voltage, the system maintains efficiency and reduces complexity.

[0248]

[0242] In embodiments where the system is integrated into a fence energiser, the controller is configured to adapt the peak voltage of the energy-storing device based on the elapsed time, inferred load or impedance across the electrodes. For example, if the fence is shortened, the overall impedance decreases, which can cause the voltage to rise to an unsafe level. In such cases, the controller, as it is configured to do, will reduce the peak voltage of a second electrical stimulus to lower the voltage across the electrodes once it determines the operational characteristics of a first electrical stimulus. This may ensure that the system operates within regulatory limits.

[0249] Storing to memory

[0250]

[0243] The memory component (16) can be an integral part of the controller's microprocessor or a separate memory module connected to it. The memory component (16) is used to store data such as the peak voltages, reference voltages, elapsed times, and the results of the comparisons. By recording when successful or failed applications occur, the controller (2) can associate and record these application statuses to specific electrical stimulus events relating to the electrical stimulus being applied. This data can be used for monitoring the system's performance over time, diagnosing issues, or adapting the system's operation based on historical data, in particular, in one embodiment, the controller records when an electrical stimulus is applied, and the associated result whether it be a successful or failed application. Stimulus events may comprise one or more of; a timestamp of when the stimulus occurred; a location of where the stimulus occurred; and whether the stimulus was a successful or failed application, or a measure of success of the application.

[0251] Measure of success and Failure / Success

[0252]

[0244] The operational characteristic derived from the elapsed time measurement directly relates to the measure of success of the electrical stimulus to the being. By measuring the time it takes for the voltage across the capacitor (4) to decay to the reference voltage, the system (1) can assess how effectively the electrical stimulus was delivered to the being through the electrodes (33). This assessment can be interpreted in two ways - a continuum of success, or binary success and failure.

[0253]

[0245] The elapsed time can represent a continuum on the measurement of success. Shorter elapsed times indicate a faster voltage decay, which suggests a significant load is present, meaning the being is in good contact with the electrodes (33), allowing for efficient energy transfer. Conversely, longer elapsed times indicate a slower voltage decay, suggesting less effective contact or higher impedance, which means the energy transfer was less successful. By analysing the exact value of the elapsed time, the controller is configured to determine varying degrees of successfulness, enabling adjustments to operational parameters for optimal performance.

[0254]

[0246] Alternatively, the controller is configured to interpret the elapsed time in a binary manner based on a predetermined reference time. If the elapsed time is below a predetermined reference time, it corresponds to a positive condition, indicating that a being is present at the electrode pair (33) to receive the electrical stimulus. If the elapsed time is above the predetermined reference time, it corresponds to a failed application, indicating that no being is present at the electrode pair (33). This binary approach simplifies the assessment, allowing the controller (2) to make quick decisions on whether to adjust operational parameters or record specific events in the memory component (16). The predetermined reference time may be determined experimentally as discussed herein. Figure 5 shows a table including a column of the average time between an Open load and 400R Load in microseconds. In this example, a successful application of the electrical stimulus is determined as an elapsed time below the average, and a failed application of the electrical stimulus is determined as an elapsed time above the average.

[0255]

[0247] In one embodiment where the system is integrated into an animal collar, the controller (2) is configured to apply a further electrical stimulus after a previously determined failed application. The controller (2) may be further configured to keep applying electrical stimuli, or to incrementally increase the voltage of the electrical stimulus, until a successful application is determined. This adaptive approach ensures that the electrical stimulus effectively reaches the animal, potentially enhancing the collar's effectiveness.

[0256]

[0248] In one embodiment, the controller (2) is configured to utilise LED indicators to display the measure of success for each electrical stimulus delivered. The system uses a colour-coded scheme where a green LED illuminates to indicate a successful application, suggesting effective contact and energy transfer to the being. A yellow LED signifies a moderate success level, indicating that the electrical stimulus was delivered but with less optimal conditions, possibly due to higher impedance or partial contact. A red LED indicates a failed application, suggesting that the electrical stimulus did not effectively reach the being, likely due to a no-load condition or poor contact at the electrodes (33). This visual feedback allows users to quickly assess the system's performance and make any necessary adjustments.

[0257]

[0249] In one embodiment, the controller is configured to provide audible alerts to convey the success measure. Beeps or tones are emitted with different patterns representing varying levels of success. For example, a single short beep may indicate a successful application, a double beep may signify moderate success, and a long continuous tone could represent a failed application. These audible signals enable users to receive immediate feedback without the need to visually monitor the system, which is particularly useful in scenarios where visual indicators may not be easily observed.

[0258]

[0250] In one embodiment, the controller (2) is configured to record the measures of success over time in its memory component to identify trends, such as decreasing effectiveness due to electrode wear or changes in the being's behaviour. By analysing this historical data, the system can detect patterns that may indicate the need for maintenance or adjustment. For instance, a gradual increase in failed applications could suggest that the electrodes are wearing out or that the being's skin resistance has changed. The controller is configured to adjust operational parameters based on these trends to maintain optimal performance.

[0259]

[0251] Furthermore, the controller may adjust the interpretation of the success measure based on environmental factors that affect electrical conductivity, such as temperature, humidity, or other external conditions. The system is configured to monitor these factors and compensate for their influence on impedance and voltage decay characteristics. For example, higher humidity levels can lower skin resistance, potentially altering the expected voltage decay rate. By accounting for these variables, the controller ensures that the assessment of electrical stimulus success remains accurate, and the system operates effectively under varying environmental conditions.

[0260] First and Second

[0261]

[0252] In various embodiments, the second electrical stimulus can occur at different times relative to the first, providing flexibility in how the system responds to detected conditions. The second electrical stimulus refers to any later stimulus applied after the first which is controlled relative to the first, regardless of whether there are intervening stimuli. In one embodiment, the second electrical stimulus is directly subsequent to the first with no intervening stimuli, allowing the controller to promptly apply another stimulus if the initial one was a failed application. In another embodiment, the second electrical stimulus follows the first electrical stimulus but includes intervening electrical stimuli, meaning the second electrical stimulus is applied after one or more additional stimuli have been delivered. This flexibility allows the controller to adapt its operation based on the outcomes of previous stimuli, adjusting operational parameters such as peak voltage.

[0262]

[0253] In one embodiment, the controller (2) is configured to vary the timing between first and second electrical stimuli based on the inferred load conditions or measure of success. If the first electrical stimulus is a failed application, the controller might wait for a specific period before applying the next stimulus, allowing time for conditions to change or for the being to come into contact with the electrodes (33).

[0263]

[0254] In some embodiments, the controller (2) is configured to allow the user to define the voltage and / or timing of stimuli. The controller is configured to follow a customised stimulus plan, applying the second electrical stimulus according to user preferences or specific application requirements.

[0264] Preferred Chronological Approach

[0265]

[0255] In a preferred embodiment, the controller (2) is configured to receive an instruction, or determine, to provide an electrical stimulus. Upon receiving this instruction, the controller (2) is configured to initiate the charging of the capacitor (4) to a predetermined peak voltage. During the charging process, the controller (2) is configured to continuously measure the voltage across the capacitor (4) using the voltage measuring device (8) and utilise the comparator (13) to determine when the measured voltage reaches the desired peak voltage. Once the measured voltage meets the predetermined peak voltage, the controller (2) is configured to stop the charging process.

[0266]

[0256] After the capacitor (4) is charged to the desired peak voltage, the controller (2) is configured to calculate the reference voitage by determining a predefined proportion of this peak voltage. In one embodiment, the controller (2) is configured to wait for the digital-to-analogue converter (11) to settle from the peak voltage to the reference voltage. This settling period takes a few milliseconds. This settling time ensures that the digital-to-analogue converter (11) accurately outputs the reference voltage for comparison.

[0267]

[0257] Once the digital-to-analogue converter (11) has settled and is outputting the reference voltage, the controller (2) is configured to instruct the timer (10) to start timing. On the timer's first tick, the timer (10) controls the trigger switch (6) to discharge the capacitor (4) through the output transformer (30). As the capacitor (4) discharges, the voltage across it begins to decay. The comparator (13) is configured to continuously compare the real-time voltage measurement from the voltage measuring device (8) to the reference voltage provided by the digital-to-analogue converter (11).

[0268]

[0258] When the measured voltage equals or falls below the reference voltage, as determined by the comparator (13), the timer (10) is configured to output the elapsed time since discharge began. The elapsed time is used by the controller (2) to derive one or more operational characteristics across the electrode pair (33).

[0269] Analogue / Digital

[0270]

[0259] The use of analogue comparisons via the comparator (13) is advantageous because analogue circuits can operate at higher speeds than their digital counterparts and do not require as much processing power from the controller (2). This efficiency allows the controller (2) to allocate more resources to other tasks, such as adjusting operational parameters, recording data, or communicating with other system components. By reducing the computational load, the system can achieve faster response times and improved overall performance. Digital and analogue signals, both input and output, are shown in Figure 4, with digital signals indicated by non-dashed arrows, and analogue signals indicated by dashed arrows.

[0271]

[0260] It is possible to perform the measurements using digital methods. A high-speed analogue-to-digital converter, such as one running at 2.5 MHz, can be integrated within the microprocessor of the controller (2) to sample the voltage decay directly. This digital sampling allows the processor to compute the elapsed time and infer the load based on the collected data. However, digital methods may face challenges due to processing limitations, especially if the microprocessor is handling multiple tasks simultaneously. High-speed data acquisition and processing can consume significant computational resources, potentially slowing down other critical functions of the controller (2). This could affect the responsiveness and efficiency of the system (1).

[0272] First Transformer

[0273]

[0261] In one embodiment, the system (1) comprises a first transformer (9) configured to receive energy directly or indirectly from the power source (5) and step up its voltage. In one embodiment, the voltage turn ratio of the first transformer (9) is 1:15. The input to the first transformer (9) is an alternating current (AC) of about 2 amperes (up to 8 amperes) at approximately 4 volts, matching the typical voltage range of the battery (5), which is between 3 and 5 volts, and preferably 4.2 volts. The first transformer (9) steps up this input to an output of around 50 milliamperes at 600 volts. In one embodiment, the input into the first transformer (9) is a sawtooth AC waveform derived from the battery (5). The capacitor (4) is charged to output voltages between 250 and 650 volts. The output transformer (30) then steps up this voltage to deliver the electrical stimulus across the electrode pair (33). In one embodiment, the first transformer increases the power source volts to a range between 400 volts and 800 volts, in another embodiment the first transformer increases the power source volts to a range between 500 and 700 volts.

[0274] Voltage Divider

[0275]

[0262] In one embodiment, the voltage measurement device (8) comprises a voltage divider, which in one embodiment, is a simple circuit consisting of two or more resistors connected in series across the voltage to be measured. The voltage divider works by distributing the voltage proportionally across the resistors based on their resistance values. By selecting appropriate resistor values, the high voltage across the capacitor (4) can be scaled down to a lower voltage that is safe and suitable for the analogue- to-digital converter (12) to measure. For example, if the capacitor (4) outputs voltages in the range of 250 to 650 volts, the voltage divider can reduce this voltage by a factor of 100 or more, allowing the use of smaller and cheaper components in the measurement circuitry.

[0276]

[0263] In one embodiment, the voltage divider is configured to handle the high voltages output by the capacitor (4), which are typically between 100 and 1000 volts, and preferably between 250 volts and 650 volts. The voltage divider reduces this high voltage by a factor of at least 50, 100, 200, or 400, depending on the specific embodiment, making it suitable for processing by lower-voltage components like the analogue-to-digital converter (12). Figure 5 shows examples of the voltage at the capacitor (4), and the associated voltages at the analogue-to-digital converter (12) which is the divided voltage received from the voltage divider (8).

[0277]

[0264] By measuring lower voltages, the system can utilise components that are less expensive, smaller in size, and more readily available. This not only reduces the overall cost of the system (1) but also enhances its reliability and safety, as components designed for lower voltages are often more robust in terms of manufacturing tolerances and thermal performance. Additionally, the use of low- voltage components simplifies the design and allows for a more compact and efficient system.

[0278]

[0265] In one embodiment, the voltage divider is a frequency compensated voltage divider. This means it includes capacitive elements in parallel with the resistive elements to ensure accurate voltage measurements across a range of frequencies, especially during the rapid voltage changes when the capacitor (4) discharges. The frequency compensation minimises errors caused by the parasitic capacitance and inductance in high-speed or high-frequency circuits.

[0279]

[0266] Figure 10 shows an exemplary frequency compensated voltage divider where six 820k resistors divide into a 1 k8 resistor, and each 820k resistor is frequency compensated by a paralleled 1 nF capacitor which collectively divide into a 6.8nF capacitor.

[0280] Broad Method

[0281]

[0267] The control circuit begins by initiating and managing the charging of the capacitor, ensuring it reaches the desired voltage level. During this process, it receives a voltage measurement from between the capacitor and the primary winding of the output transformer. Once the capacitor is fully charged, the control circuit determines the peak voltage based on this measurement. It then determines the reference voltage as a proportion, such as 75%, of the peak voltage. Once the trigger switch is triggered to discharge the capacitor through the output transformer, the control circuit is configured to concurrently start a timer to measure the elapsed time. As the capacitor discharges, the control circuit continuously compares the real-time voltage measurement to the reference voltage. If the measured voltage remains above the reference voltage, It continues monitoring. When the measured voltage reaches or falls below the reference voltage, the control circuit records the elapsed time from the timer. Based on this recorded elapsed time, it derives one or more operational characteristics across the electrode pair, which may include the measure of success of the electrical stimulus delivery, the load impedance, or the presence of a being at the electrodes, and / or any adjustments to operational parameters. If adjustments are determined, the system modifies settings such as the peak voltage for future electrical stimuli based on the derived characteristics. The process may then end or loop back to the initial steps for subsequent electrical stimuli.

[0282] System Control and Adaptive Operation

[0283]

[0268] In some embodiments, the system is configured to utilise the determined operational characteristic to control its subsequent operations. The control circuit (2) may be configured to process the inferred information about the stimulus delivery and generate one or more control signals to adjust a variety of operational parameters. This adaptive capability may enhance the system's effectiveness, safety, and diagnostic utility. The following exemplary functions describe various operational parameters that the system is configured to control based on the determined operational characteristic.

[0284]

[0269] In one embodiment, an operational parameter controlled by the system is a subsequent, or second, electrical stimulus. After a first electrical stimulus is delivered and its operational characteristic is determined, the control circuit (2) can modify the parameters of the next stimulus to optimise its performance. For example, if the determined characteristic indicates a failed application, e.g., a long voltage decay time suggesting high impedance, the control circuit (2) may be configured to increase the peak voltage of the capacitor (4) for the second electrical stimulus. This increase in energy can help overcome a higher-than-expected impedance, such as an air gap between an electrode and a being, thereby increasing the likelihood of a successful subsequent application. Conversely, if a successful application is determined, the system may maintain or even reduce the voltage for the next stimulus to conserve energy. In another embodiment, the operational parameter comprises the physical or electrical configuration of the circuit itself. For instance, the control circuit (2) may be configured to adjust the number of capacitors active in the capacitor circuit. In an embodiment where the capacitor circuit (4) comprises a bank of multiple capacitors, the control circuit can issue commands to switching elements connected to said capacitors. Based on a determined need for higher or lower stimulus energy, the controller can bring additional capacitors into the connected capacitor circuit to increase the total capacitance and stored energy, or take capacitors out of the connected capacitor circuit to reduce it. This provides a method for making adjustments to the energy output based on the operational characteristics.

[0285]

[0270] In one embodiment, the operational parameter is the decision to temporarily disable further electrical stimulus application. If the control circuit (2) determines an operational characteristic indicative of a persistent fault, such as a series of consecutive failed applications suggesting a continuous opencircuit condition, or the detection of arcing events, it can enter a safe mode. In this mode, the controller is configured to inhibit the trigger signal to the trigger switch (6), preventing the application of any further stimuli until the fault condition is resolved or a predetermined reset condition is met. This safety interlock may prevent the system from operating in potentially unsafe conditions. In another embodiment, the operational parameter comprises an event logging command. Upon determining the operational characteristic of a stimulus event, the control circuit (2) is configured to generate a command to store data related to that event in the memory component (16). This logged data may include the determined characteristic (e.g., success, failure, inferred impedance), the measured elapsed time, the peak voltage of the stimulus, and a timestamp. This function allows the system to build a historical record of its performance, which may be used for diagnostics, trend analysis (such as detecting stimulus weakening over time), and performance monitoring. In another embodiment, the operational parameter relates to user interaction. The operational parameter comprises generating an alert or an alert communication. Based on the determined operational characteristic, the control circuit (2) can activate various user feedback mechanisms. For example, it may drive an LED indicator, illuminating a light for a successful application and a visually distinct light for a failed one. Alternatively, it can generate a signal for an audible alert, such as a short beep for success and a long tone for failure. Furthermore, an "alert communication" may comprise sending a data packet via a wired or wireless communication interface to a remote monitoring system or a user mobile device, providing real-time status updates on the system operation.

[0286] Applications

[0287]

[0271] The system (1) can be integrated into an electric fence energiser for delivering high-voltage electrical stimuli via the electrode pair (33) to an electric fence. Alternatively, it can be incorporated into a wearable animal device, such as a collar, for delivering electrical stimuli through the electrode pair (33) positioned to contact or be proximal to an animal in operation. The being is typically an animal or person, and in one embodiment, the animal is a large animal over 100kg, such as a cattle animal.

[0288]

[0272] The control circuit (2) is configured to measure only the capacitor voltage or first transformer voltage and is not configured to measure current. This simplifies the system's design and reduces cost and complexity, as measuring high currents requires more expensive and bulky components. By focusing on voltage measurements and utilising the voltage decay characteristics, the system can infer information about the load and the effectiveness of the electrical stimulus without direct current measurement.

[0289]

[0273] The system may be used in other similar high voltage circuits that are configured to provide high voltage shocks over short periods of time, utilising a transformer which has a low voltage primary side.

[0290]

[0274] Other aspects of the load may also be inferred by the controller based on the elapsed time. Such aspects may relate to if the fence is broken or heavily loaded (e.g,, vegetation touching the fence). The system may detect a slower voltage decay, triggering an alert or adjusting the electrical stimulus parameters to maintain safety.

[0291]

[0275] Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth.

[0292]

[0276] Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and / or improvements may be made without departing from the scope or spirit of the invention.

[0293] Reference Numerals

[0294] System 1; Animal 3; Wearable Device 100; Controller 2; Output Transformer 30; Primary-’ Winding 31; Secondary Winding 32; Output Terminals / Electrodes 33; Capacitor / Capacitor Circuit 4; Battery 5; Trigger Switch 6; Charge Switch 7; Voltage Measurement / Voltage Divider 8; First Transformer 9; Timer 10; digital-to-analogue converter 11; analogue-to-digital converter 12; Comparator 13; Charge Control 14; Boost Transformer 15; Memory component 16.

Claims

CLAIMS1. An electrical stimulus system configured to apply an electrical stimulus to a being, the system comprising:a power source;a capacitor circuit;an output transformer comprising a primary winding and a secondary winding configured to output the electrical stimulus to one or more electrodes;a switching element configured to connect the capacitor circuit to the primary winding; and a control circuit configured to:(i) control a first electrical stimulus by initiating a discharge of the capacitor circuit through the primary winding via the switching element;(ii) during the discharge, determine a voltage decay characteristic of the capacitor circuit;(iii) determine an operational characteristic of the first electrical stimulus based on the determined voltage decay characteristic; and(iv) generate a control signal for controlling an operational parameter of the system based on the determined operational characteristic,2. The system as claimed in claim 1, wherein the control circuit determines the voltage decay characteristic by determining an elapsed time for a voltage of the capacitor circuit to fall from a first voltage to a reference voltage.

3. The system as claimed in any one of the preceding claims, wherein the operational parameter of the system comprises a second electrical stimulus.

4. The system as claimed in claim 3, wherein the control circuit is configured to apply the second electrical stimulus if the first electrical stimulus was determined to be a failed application.

5. The system as claimed in claim 4, wherein the control circuit is configured to apply the second electrical stimulus at a higher voltage than the first electrical stimulus.

6. The system as claimed in any one of the preceding claims, wherein the operational parameter of the system comprises one or more of:the number of capacitors active in the capacitor circuit;a command to temporarily disable further electrical stimulus application; an event logging command; anda command for generating an alert or an alert communication.

7. The system as claimed in any one of the preceding claims, wherein the operational characteristic is related to one or more selected from the group consisting of:the voltage of the one or more electrodes,a measure of success of the electrical stimulus,the load of the one or more electrodes,the resistance of the one or more electrodes,the impedance of the one or more electrodes,a fault of the one or more electrodes, andarcing from the one or more electrodes.

8. The system as claimed in any one of claims 2 to 7, wherein the first voltage is based on a peak voltage of the capacitor circuit when the discharge is initiated.

9. The system as claimed in claim 8, wherein a measurement of the peak voltage is taken at the time of triggering the switching element.

10. The system as claimed in any one of claims 2 to 9, wherein the control circuit determines the operational characteristic based on the elapsed time being above or below a predetermined reference time.

11. The system as claimed in claim 10, wherein an elapsed time below the predetermined reference time corresponds to a successful application of the electrical stimulus, and an elapsed timeabove the predetermined reference time corresponds to a failed application of the electrical stimulus.

12. The system as claimed in claim 11, wherein the predetermined reference time for the successful application is between 3 and 4 microseconds.

13. The system as claimed in claim 11, wherein the predetermined reference time for the failed application is selected from the group consisting of: more than 4 microseconds, between 4 and 9 microseconds, and between 6 and 7 microseconds.

1. The system as claimed in any one of claims 2 to 13, wherein the reference voltage is a predefined proportion of the first voltage.

15. The system as claimed in any one of the preceding claims, wherein the control circuit comprises a voltage measuring device configured to provide a scaled-down voltage representative of the voltage of the capacitor circuit.

16. The system as claimed in claim 15, wherein the voltage measuring device comprises a voltage divider.

17. The system as claimed in claim 16, wherein the voltage divider is a frequency compensated voltage divider.

18. The system as claimed in any one of the preceding claims, wherein the control circuit comprises a comparator.

19. The system as claimed in any one of the preceding claims, wherein the control circuit comprises a timer module.

20. The system as claimed in any one of the preceding claims, wherein the control circuit comprises an analogue-to-digital converter configured to measure the voltage of the capacitor circuit.

21. The system as claimed in any one of the preceding claims, wherein the control circuit comprises a digital-to-analogue converter.

22. The system as claimed in any one of claims 18 to 21, when dependent on claim 2, wherein the comparator is configured to receive the voltage of the capacitor circuit and the reference voltage and to control a comparator output state.

23. The system as claimed in any one of claims 19 to 22, wherein the timer module is configured to determine the elapsed time based, at least in part, on the comparator output state.

24. The system as claimed in any one of claims 21 to 23, wherein the digital-to-analogue converter is configured to provide the reference voltage to the comparator.

25. The system as claimed in any one of claims 21 to 24, wherein the control circuit is configured to receive the voltage measured by the analogue-to-digital converter and to control the digital-to- analogue converter based on the received voltage.

26. The system as claimed in any one of the preceding claims, wherein the control circuit is further configured to control stimulus output based on operation of the switching element.

27. The system as claimed in any one of the preceding claims, wherein the control circuit comprises a charge switch operable to control connection of the capacitor circuit with the power source.

28. The system as claimed in any one of the preceding claims, wherein the control circuit is configured to record when a successful application or a failed application occurs.

29. The system as claimed in any one of the preceding claims, wherein the control circuit is configured to adapt one or more operational parameters of the system based on the determined operational characteristic.

30. The system as claimed in claim 29, wherein the one or more operational parameters relate to one or more selected from the group consisting of:a capacitance of the capacitor circuit,a length of time between charging and discharging the capacitor circuit,energy stored in the capacitor circuit, anda time until a second electrical stimulus is applied.

31. The system as claimed in any one of the preceding claims, wherein controlling the charging of the capacitor circuit controls the voltage of the electrical stimulus.

32. The system as claimed in any one of the preceding claims, wherein the system comprises a first transformer configured to receive energy from the power source and to step up the voltage of the power source to charge the capacitor circuit.

33. The system as claimed in any one of the preceding claims, wherein the output transformer is configured to step up the voltage to a range between 100V and 20kV.

34. The system as claimed in any one of the preceding claims, wherein the system is integrated into a wearable animal device for delivering the electrical stimulus through the one or more electrodes.

35. A wearable device for a cattie animal, comprising the electrical stimulus system as claimed in any one of claims 1 to 34.

36. A method of inferring a load across one or more electrodes of an electrical stimulus system, the system comprising a power source, a capacitor circuit, an output transformer having a primary winding and a secondary winding, a switching element, and a control circuit, the method comprising the steps of:(a) controlling, by the control circuit, the charging of the capacitor circuit via the power source;(b) initiating, by the control circuit, a discharge of the capacitor circuit through the primary winding by operating the switching element, thereby causing the secondary winding to output an electrical stimulus to the one or more electrodes;(c) determining, by the control circuit, a voltage decay characteristic of the capacitor circuit during the discharge; and(d) determining, by the control circuit, an operational characteristic of the electrical stimulus based on the determined voltage decay characteristic.

37. The method as claimed in claim 36, wherein the step of determining the voltage decay characteristic comprises determining an elapsed time for a voltage of the capacitor circuit to fall from a first voltage to a reference voltage.

38. The method as claimed in claim 37, further comprising the step of comparing the determined elapsed time to a predetermined time threshold to determine the operational characteristic.

39. The method as claimed in claim 38, wherein an elapsed time below the predetermined time threshold indicates a successful application of the electrical stimulus to a being, and an elapsed time above the predetermined time threshold indicates a failed application of the electrical stimulus.

40. The method as claimed in any one of claims 36 to 39, further comprising the step of: (e) generating, by the control circuit, a control signal for controlling an operational parameter of the system based on the determined operational characteristic.

41. The method as claimed in claim 40, wherein the operational parameter of the system comprises a second electrical stimulus.

42. The method as claimed in claim 40, wherein the operational parameter of the system comprises one or more of:the number of capacitors active in the capacitor circuit;a command to temporarily disable further electrical stimulus application;an event logging command; anda command for generating an alert or an alert communication.

43. The method as claimed in any one of claims 36 to 42, wherein the step of determining the voltage decay characteristic comprises measuring a voltage of the capacitor circuit via a voltage divider.

44. The method as claimed in claim 43, wherein the voltage divider is a frequency compensated voltage divider.

45. The method as claimed in any one of claims 37 to 44, wherein the control circuit determines the reference voltage based on a peak voltage measured through the voltage divider.

46. The method as claimed in any one of claims 37 to 45, wherein the step of determining the elapsed time comprises:comparing, via a comparator, an analogue voltage measurement from the voltage divider to the reference voltage; andoutputting a signal from the comparator when the analogue voltage measurement falls below the reference voltage,wherein the signal is used to determine the elapsed time.

47. The method as claimed in any one of claims 36 to 46, wherein the control circuit comprises a timer, and wherein the step of initiating the discharge comprises the timer controlling the switching element upon commencement of timing.

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