Enhanced non-linear motor control and operation of oral hygiene products

Abstract

Systems and methods for enhanced non-linear motor control and operation of oral hygiene products are discussed. A controller of a oral hygiene device calculates a revolutions per minute (RPM) of a motor of the oral hygiene device based on a current measurement signal for a current through the motor generated by a current sensing circuit of the oral hygiene device and adjusts a switch operation signal that controls a switching of a battery of the oral irrigator to the motor to drive the RPM of the motor to a desired RPM that corresponds to a desired pulse rate for pulses of fluid ejected from the oral hygiene device. The controller (additionally or alternatively) formulates, based on measurements of the battery, the switch operation signal to control the switching of the battery to the motor to target a target effective voltage at the motor.

Description

Docket No. P324043.W0.01ENHANCED NON-LINEAR MOTOR CONTROL AND OPERATION OF ORAL HYGIENE PRODUCTSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63,746 / 639, filed January 17th, 2025, entitled “ENHANCED NON-LINEAR MOTOR CONTROL AND OPERATION OF ORAL HYGIENE PRODUCTS,” which is hereby incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to health and personal hygiene equipment and more particularly, to oral irrigators.BACKGROUND

[0003] Oral irrigators allow people to remove food particles, plaque, and bacteria from difficult to reach areas in the mouth, such as between teeth and the area along the gumline. Generally, oral irrigators use a motor to pump a fluid into the user's mouth. The motor of the oral irrigator affects the quality of the overall user experience, including cleaning efficiency and user sensation.SUMMARY

[0004] Disclosed herein are devices and methods to improve motor control for motorized oral hygiene products.

[0005] In one embodiment, an oral hygiene device is disclosed. The oral hygiene device may include a handle fluidly coupled to a tip, a motor operably coupled to the handle, a controller in electronic communication with the motor and operably coupled to the handle. The controller may be configured to modify at least one fluid characteristic of fluid output by the tip by modifying an electrical current signal applied to the motor to change an operating characteristic of the motor.

[0006] In one embodiment, an oral hygiene device is disclosed. The oral hygiene device may include a handle in fluid communication with a reservoir and a tip, a motor in mechanical communication with a pump, a controller in electrical communication with a sensing module and the motor and operably coupled to the handle, and a memory module in communication 14906-4427-8396\2Docket No. P324043.W0.01with the controller. The pump may be in fluid communication with the reservoir and the tip. The controller and the sensing module may use a feedback control loop to control an operating characteristic of the motor.

[0007] Embodiments of the present disclosure include a method to control an oral hygiene device. The method may include determining a desired operating characteristic of a motor, setting a current signal to the motor based on the desired operating characteristic, detecting the current signal applied to the motor, adjusting the current signal, and modifying the current signal applied to the motor.

[0008] Embodiments of the present disclosure include an oral irrigator that includes a pump configured to eject pulses of fluid from the oral irrigator, a motor operably connected to the pump, wherein a pulse rate of the pulses of fluid ejected from the oral irrigator by the pump corresponds to a revolutions per minute (RPM) of the motor; a switch that switches a power source used by the oral irrigator to the motor; a current sensing circuit that generates a current measurement signal for a current through the motor; and a controller connected to the current sensing circuit and that generates a switch operation signal that operates the switch, wherein the controller: receives the current measurement signal from the current sensing circuit; and adjusts, based on the current measurement signal, the switch operation signal to drive the RPM of the motor to a desired RPM that corresponds to a desired pulse rate for the pulses of fluid such that the pulse rate of the pulses of fluid is driven to the desired pulse rate.

[0009] Embodiments of the present disclosure include an oral irrigator that includes a pump configured to eject pulses of fluid from the oral irrigator, a motor operably connected to the pump; a switch that switches a battery used by the oral irrigator to the motor; and a controller that generates a switch operation signal that operates the switch, wherein the controller: measures the battery during a first battery measurement period to determine one or more first battery characteristics of the battery during the first battery measurement period; and formulates, based on the one or more first battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, a target effective voltage at the motor.

[0010] Embodiments of the present disclosure include an oral irrigator that measures a battery used by the oral irrigator during a first battery measurement period to determine one or more first battery characteristics of the battery during the first battery measurement period; formulates, based on the one or more first battery characteristics, a switch operation signal to 24906-4427-8396\2Docket No. P324043.W0.01target, based on a switching of the battery to a motor of the oral irrigator by a switch of the oral irrigator that is controlled by the switch operation signal, a target effective voltage at the motor; and adjusts, based on a current measurement signal for a current through the motor generated by a current sensing circuit of the oral irrigator, the switch operation signal to drive an RPM of the motor to a desired RPM that corresponds to a desired pulse rate for pulses of fluid ejected from the oral irrigator such that a pulse rate of the pulses of fluid is driven to the desired pulse rate.

[0011] While multiple examples are disclosed herein, still other examples of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples of the invention. As will be realized, the invention is capable of modifications in various aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 depicts an example oral irrigator.

[0013] FIG. 2 depicts an example of a system of an oral hygiene device that includes a controller.

[0014] FIG. 3 depicts an example of a feedback control loop method as may be used in an oral hygiene device.

[0015] FIG. 4A illustrates an oral irrigator.

[0016] FIG. 4B illustrates a close-up view of a charging assembly of the oral irrigator.

[0017] FIG. 5 illustrates a circuit diagram for circuitry of an oral irrigator.

[0018] FIG. 6A illustrates an example waveform for an I SENSE signal that represents a current through a motor over time as detected by a controller.

[0019] FIG. 6B illustrates a portion of the waveform of FIG. 6A near a first local maxima.

[0020] FIG. 7 illustrates a method of an oral irrigator, according to embodiments discussed herein.

[0021] FIG. 8 illustrates a method of an oral irrigator, according to embodiments discussed herein.34906-4427-8396\2Docket No. P324043.W0.01

[0022] FIG. 9 illustrates a method of an oral irrigator, according to embodiments discussed herein.DETAILED DESCRIPTION

[0023] Use of a motorized oral hygiene device is an excellent method to maintain oral hygiene. For example, an oral irrigator typically uses a motor to drive a pump to pulse fluid into the user's mouth at a desired pressure and rate. Motor control is vital to the user experience and cleaning efficacy. However, the relationship between the motor and its power source may create undesirable changes to the user experience. For example, many oral irrigators, such as handheld versions, rely on a battery as the power source. The battery’s ability to produce electricity degrades as it ages, resulting in decreased motor output. The lower motor output could lead to a loss of fluid pressure or a lower pulsation rate, negatively affecting the user experience, both in cleaning efficiency and user sensation. In another example, an oral hygiene device using a battery may also experience a voltage spike upon start up, which also affects an operating characteristic of the motor. Oral hygiene devices may compensate for these fluctuations in power by controlling the motor. Typically, an oral hygiene device utilizes a voltage signal to control a motor. However, monitoring voltage and utilizing voltage signals can result in inconsistent changes in an operating characteristic of the motor. For example, a step change in voltage may not result in step change in motor performance as there is typically not a direct correlation to a particular voltage signal and a fluid characteristic output by the oral irrigator.

[0024] In various embodiments, a hygiene device and method with improved control over the motor is disclosed as compared to conventional solely voltage controlled device. Better control over the motor allows for better user experience, e.g., providing a more stable fluid pressure, pulsation rate, etc. In addition, improved motor control benefits corded motorized oral hygiene devices as well, such as wall powered devices or other alternating current (AC)-powered oral hygiene devices.

[0025] For example, embodiments include utilizing controlling the current applied to the motor to change the operating characteristic of the motor, e g., to modify the ultimate fluid flow characteristics of the oral irrigator. Current control may include utilizing current value signals and sensing current feedback from the motor (rather than utilizing voltage values), which has a more direct impact on the torque of the motor compared to voltage. This allows for44906-4427-8396\2Docket No. P324043.W0.01an easier understanding and more refined control of the fluid characteristics output by the oral irrigator than conventional devices.

[0026] More specifically, in some examples, the oral irrigator or other oral hygiene device may control the motor by employing a control module, e.g., a controller. A controller alters motor performance, to compensate for power fluctuations. In some cases, the controller can change the motor’s operation in response to a detected a signal from a sensing module. The change in operation allows a generally consistent operating characteristic of the motor. More sophisticated designs may use a feedback loop to maintain an operating characteristic of the motor over a period of time. For example, an oral hygiene device may set a desired output, such as a pressure output. The controller would then change the motor’s output based on the desired output. The sensing module may detect a signal directly correlated to the desired output. If the sensing module detects a signal that does not correlate to the desired output, the controller may modify the operating characteristic of the motor to match to the desired output. The sensing module would again detect a signal correlated to the desired output, and the process repeats to maintain the desired output. A controller that modifies electrical current to change the operating characteristic of the motor provides enhanced motor control. In the case of some motors, the relationship between motor performance and electrical current has been found to be directly proportional. Thus, a control mechanism that relies on modifying the current can more consistently and efficiently tune a motor's performance to match a desired operating characteristic of the motor of the oral hygiene device, e.g., pressure, pulse rate, etc.

[0027] Optionally, an oral hygiene device may further benefit when a controller modifies current values and includes a motor configured to maintain a constant rotational rate across a range of current values (e g., consistent RPM despite current value variation). Such consistent motor rotational output helps to ensure consistent pulse rates of fluid despite variations in fluid pressure (e.g., a constant fluid pulse rate but at different fluid pressures). In main instances, pulse rate for irrigators may be desirable for cleaning efficacy or comfort to be within a certain range but having flexibility to change the pressure of the fluid will allow more user customization and comfort as compared to conventional devices. Conventional devices may include motors that when experiencing a different voltage signal will also include a change in rotational rate as well, impacting both the fluid output pressure and the fluid pulse rate. In various embodiments, described herein, however, the motor may compensate for the torque produced at different current values, while maintaining the same rotational rate, which can be 54906-4427-8396\2Docket No. P324043.W0.01more efficiently and consistently managed with a controller that modifies electrical current to adjust an operating characteristic of the motor.

[0028] Turning to the figures, FIG. 2 depicts an example of a system 200 of the oral irrigator 100 that may be used to control an oral irrigator 100. System 200 includes a motor 202, a power source 204, and a controller 210. Optionally, System 200 may include a memory 206, a control button 208, and a sensing module 212.

[0029] A controller 210 modifies the current applied to the motor 202. By modifying current, rather than voltage, the controller 210 may effect changes to the output of motor 202 with more consistency and efficiency. For example, with certain motor designs, the relationship between voltage and motor output has been found to be represented by the following relationship as shown below by Eq. (1):Where V represents voltage, kerepresents the back electromotive force constant, co represents angular frequency, r represents torque, kt represents a torque coefficient, and R represents resistance. Torque effectively represents motor output since the two are directly correlated. Here, voltage has an additive relationship with torque. Thus, a step change in the voltage applied to a motor does not necessarily result in a corresponding step change in torque. In contrast, the relationship between current and torque with the same type of motors can be expressed by the following relationship as shown below by Eq. (2):T = I ■ ktEq. (2)where I represents current. Since the electrical current is directly proportional to torque, a step change made to the electrical current applied to the motor results in a step change to the torque produced by the motor.

[0030] System 200 may allow a user to use a control button 208 (or otherwise provide an input to the oral irrigator) to achieve a desired fluid output characteristic, such as fluid pressure. In various embodiments, the control button 208 may include a dial, a turn knob, a slide switch, or a push button. In some embodiments, the control button 208 is the same as the control actuator 113. By adjusting the control button 208, the controller 210 applies different amounts of currents to the motor. This allows a user to experience a step change in an operating64906-4427-8396\2Docket No. P324043.W0.01characteristic of the motor by making a step change adjustment with the control button 208. For example, actuating a push button of an oral irrigator may change the fluid pressure by applying different amounts of current to the motor 202. Due to the direct and linear relationship between current and motor performance, actuating the push button can more efficiently and consistently achieve the desired fluid pressure. Thus, the controller 210 can achieve a desired operating characteristic of the motor more efficiently and consistently than a controller that modifies voltages applied to a motor.

[0031] By modifying electrical current, controller 210 also compensates for instability with a power source 204. In some embodiments, power source 204 may include a battery. In other embodiments, power source 204 may include a wall socket, e.g., a 120-volt socket or 240-volt socket. Power source 204 may experience instability, e.g., a battery’s ability to produce electrical energy declines as it ages. As the power source 204 declines or fluctuates, controller 210 may modify the current to maintain a desired operating characteristic of the motor of motor 202. Again, due to the relationship between current and torque of motor 202, the controller 210 can more efficiently compensates for changes from the power source 204 than by modifying voltage.

[0032] In some embodiments, System 200 may include a sensing module 212. The sensing module 212 may be in communication with controller 210 and configured to receive, store and send data with controller 210. For example, sensing module 212 may communicate with controller 210 via an electrical wire, and / or a wireless network. Sensing module 212 may detect a signal corresponding to an operating characteristic of the motor. For example, signals sensing module 212 may detect an electrical signal, e.g., a current signal, corresponding to a fluid pressure ejected from tip 114, a rate of pulses of fluid ejected from tip 114, a rotational rate produced by motor 202, or a torque produced by motor 202. Controller 210 may then modify the current applied to motor 202 based on the signal detected by sensing module 212.

[0033] In some embodiments, the System 200 may include memory 206. Memory 206 may store data inputs or instructions to maintain a desired operating characteristic of the motor. In some embodiments, the data inputs may come from any of the motor 202, the control button 208, the controller 210, and / or the sensing module 212. For example, a user may set a desired fluid pressure by actuating control button 208. The sensing module 212 may detect rotational rate of motor 202 at the desired fluid pressure. The rotational rate data may then be stored on memory 206 so that the desired fluid pressure may be maintained by System 200.74906-4427-8396\2Docket No. P324043.W0.01

[0034] FIG. 1 depicts an example of the disclosed oral hygiene device, which in this example is an oral irrigator 100. However, other oral hygiene devices are envisioned, such as an electrical toothbrush, combination oral irrigator and toothbrush, or the like. In the FIG. 1 example, the oral irrigator includes a reservoir 104 coupled to a handle 106. The reservoir 104 is in fluid communication with tip 114. In some embodiments, the reservoir 104 is movable. For example, a user may uncouple reservoir 104 from the handle 106, fill the reservoir with a fluid, and recouple the reservoir 104 to the handle 106. It should be noted that although the oral irrigator 100 is shown as a handheld device, e.g., with a fluid reservoir directly coupled to the handle 106, in other embodiments, the oral irrigator may include a countertop portion and have a separate base that supports the reservoir and may include various electronic or drive components (e.g., pump and motor 202) of the oral irrigator. To that end, any discussion of a particular implementation for the oral irrigator is meant as illustrative only.

[0035] The handle 106 (or base if a countertop unit) may be used to house operating components of the device, such as, but not limited to, a motor 202, pump, and controller 210 (e.g., the drive assembly or pump assembly). The motor 202, pump, and / or controller 210 work in conjunction to pump fluid from reservoir 104 through tip 114 and out an outlet 122 (e.g., into a user’s oral cavity). In this manner, there may be a fluid path defined from the reservoir 104, through the handle (e.g., via the pump assembly or drive assembly), and to the tip 114.

[0036] The pump may include a piston and pump housing that is in fluid communication with the reservoir 104 and the tip 114. The pump is configured to cycle or include a stroke that alternatingly pulls fluid into a pump chamber of the pump housing from the reservoir 104 and then pushes the fluid from the pump chamber to the tip 114. The pump may include various configurations (e g., gearing or the like) to create a desired output fluid characteristic (e g., pulse length, pulse force, pulse rate) for the oral irrigator.

[0037] The motor 202 is configured to drive the pump, e.g., is coupled to the piston for a piston pump and drives the pump to define the pump cycle or pump stroke. The motor 202 is in electrical communication with the controller 210 and typically includes a drive shaft coupled (e.g., gearing, cams or the like) to the piston. In this manner, as the drive shaft is rotated or otherwise moved by the motor 202, the pump is actuated to push and pull fluid. In some embodiments, the motor 202 may be able to maintain a constant operating characteristic of the motor, e.g., RPM, while controller 210 applies different current signals to motor 202. For example, controller 210 may alter the current signal to motor 202 in response to a fluctuation 84906-4427-8396\2Docket No. P324043.W0.01from power source 204. The motor 202 can maintain constant RPM with a decrease in torque. As a result, the pulsation rate is held constant and the fluid pressure is reduced. In some embodiments, this feature may be used to extend the lifetime of motor 202 by applying less current over time.

[0038] The controller 210 is in electrical communication with the motor 202. The controller 210 is configured to modify the operation of the motor. For example, the controller 210 varies the current signal applied to the motor 202 (this may be done by directly changing a current signal or other power signal to the motor 202). In some examples, such as during a particular operational setting of the oral irrigator 100, which may be selected by the user, the controller 210 modifies the current signal to maintain a consistent fluid pressure ejected from tip 114. This may include increasing or decreasing the average applied current as there are changes within the oral irrigator 100 to ensure that the downstream output of the motor (e.g., the fluid output characteristics) are consistent.

[0039] In some embodiments, the controller 210 modifies the current to control the pulsation rate at which fluid is ejected from the tip 114. For example, the controller 210 may change the current signal to the motor 202. In response, the motor 202 may speed up or slow down depending on the current signal sent by controller 210. As a result, the speed of a pump driving the fluid flow out of tip 114, in fluid communication with a reservoir 104 and in mechanical communication with motor 202, will change correspondingly. This allows a user to control the pulsation rate of an oral hygiene device, such as the oral irrigator 100.

[0040] Oral irrigator 100 may also include an activation actuator 112 and a control actuator 113. In various embodiments, the control actuator 113 may include a dial, a turn knob, a slide switch, or a push button. In some embodiments, control actuator 113 is in mechanical communication with control button 208. In some embodiments, control actuator 113 is the same as control button 208. For example, control actuator 113 may be coupled to handle 106 and accessible to a user. The user may then actuate control actuator 113 to change a setting in the oral hygiene device, e.g., the fluid pressure of oral irrigator 100. The controller 210 then modifies the current signal to motor 202 based on control actuator 113, and the operating characteristic of the motor changes accordingly.

[0041] FIG. 3 depicts a flow chart of an example feedback control loop method. The method 300 may begin with operation 302. Operation 302 determines a desired pressure output. In other embodiments, other outputs may be used, including rotational rate of the motor or94906-4427-8396\2Docket No. P324043.W0.01pulsation rate. In some embodiments, the desired output may be set by actuating control button 208. For example, a user may actuate control button 208 to achieve a desired the fluid pressure of an oral irrigator 100. In other examples, a user may adjust control button 208, such as by a dial or knob, to adjust the fluid pressure of a countertop oral irrigator. Thus, operation 302 may be performed by a user actuating or adjusting control button 208 to determine a desired fluid pressure.

[0042] Once a desired pressure output is determined in operation 302, the method 300 may proceed to operation 304. Operation 304 sets a current signal to the motor based on the pressure output. In some embodiments, the current signal takes the form of a square wave. In some embodiments, the current signal takes the form of a substantially sinusoidal wave as a result of the signal alternating between on and off. In some embodiments, pulse width modulation (PMW) is used to control the motor. For example, after a user actuates control button 208, a controller 210 in electrical communication with motor 202 may cause the voltage applied to the motor 202 to pulse on and off, resulting in a substantially sinusoidal current signal, which the motor 202 will perform according to.

[0043] The method 300 may then proceed to operation 306. Operation 306 detects the current signal applied to the motor. For example, sensing module 212 may be in electrical communication with controller 210 and may detect the current signal applied by controller 210 to motor 202.

[0044] After a current signal is detected, the method 300 may proceed to decision 308.Decision 308 determines if there is a need to adjust the current. If there is a motivation to adjust the operating characteristic of the motor, then the method 300 may proceed to operation 310. In some embodiments, a duty cycle may be adjusted. Duty cycle refers to the proportion a signal is on versus off. Changing the duty cycle may change the current signal, resulting in a change in operating characteristic of the motor. For example, if a user would like to adjust the fluid pressure of oral irrigator 100, the user may actuate control button 208. Sensing module 212 may detect the current signal in operation 306. Since the user desires a new fluid pressure, decision 308 may determine there is a motivation to adjust and the controller 210 may modify the duty cycle of the current signal to applied to motor 202 to modify the operating characteristic of the motor. The change in duty cycle may affect the amplitude and / or angular frequency of the substantially sinusoidal current signal, resulting in a direct change to the operating characteristic of the motor due to the linear relationship between current and torque.104906-4427-8396\2Docket No. P324043.W0.01

[0045] If there is no motivation to adjust the operating characteristic of the motor, then the method 300 will proceed to operation 306 to detect the current signal applied to motor.

[0046] FIG. 4A illustrates an oral irrigator 400. The view of FIG. 4A illustrates various elements transparently to facilitate the demonstration of various internal components. The oral irrigator 400 is an example of an oral hygiene device.

[0047] The oral irrigator 400 includes a housing 402 that receives, among other things, a button 404, a reservoir 406 and a tip 408. When a user of the oral irrigator 400 presses the button 404, the oral irrigator 400 pumps pulses of fluid (e g., water, a water-and-mouthwash solution) from the reservoir 406 and out through the tip 408 of the oral irrigator 400. By gripping the housing 402 and thereby manipulating the position of the oral irrigator 400, the user can maneuver the tip 408 of the oral irrigator 400 relative to the user's oral cavity in order to clean various portions of the oral cavity (e.g., teeth, gums, etc.) with the pulses of fluid that are being pumped from the tip 408.

[0048] As shown here, the reservoir 406 includes a door 410 that can be used to access the inner cavity of the reservoir 406. Via this access, a user may replace / refill the liquid of the reservoir as needed.

[0049] The oral irrigator 400 further includes, within the housing 402, a motor 412 and a pump 414 that is operated by (that is operably connected to) the motor 412. The pump 414 is fluidly connected to the tip 408 and to a tube 416. From there, the tube 416 is fluidly connected to the reservoir 406.

[0050] The motor 412 is operably connected to the pump 414. A piston 418 of the pump 414 is linked to a connecting arm 420 of a driven gear 422 that couples to a pinion gear 424 on a drive shaft 426 of the motor 412. Accordingly, revolutions of the drive shaft 426 of the motor 412 ultimately drive the piston 418 of the pump 414 between alternating vacuum and push strokes. As the motor 412 operates / actuates the pump 414 via the action of the piston 418, fluid from the reservoir 406 is drawn up through the tube 416 and into the pump 414 (on a vacuum stroke of the piston 418 of the pump 414 toward the motor 412), and from there driven out the top of the pump 414 and through the tip 408 (on a subsequent push stroke of the piston 418 of the pump 414 toward the tip 408).

[0051] For the oral irrigator 400, the driven gear 422 and the pinion gear 424 are given a relative gearing such that one full revolution of the drive shaft 426 of the motor 412 translates114906-4427-8396\2Docket No. P324043.W0.01to one full pump cycle of the pump 414 (where one full pump cycle of the pump 414 is one full vacuum stroke of the piston 418 and one full push stroke of the piston 418)

[0052] It will correspondingly be understood that ejection of fluid from the tip 408 of the oral irrigator 400 occurs in the form of pulses of said fluid that correspond to push strokes of the piston 418 of the pump 414. It will also be understood that because the piston 418 is ultimately driven according to revolutions of the drive shaft 426 of the motor 412, a rate of these pulses of fluid corresponds to an RPM of the motor 412. As described, in the case of the oral irrigator 400, the rate of these pulses of fluid (per minute) matches to the RPM of the motor 412.

[0053] The oral irrigator 400 further includes a power assembly 428 which includes, among other things, a battery 430 and a printed circuit board (PCB) 432. The battery 430 acts as a power source for power used to operate the motor 412 and various components found on the PCB 432, as discussed herein. The battery 430 may be engaged for these (and potentially other) purposes once the button 404 is pressed.

[0054] FIG. 4B illustrates a close-up view of the power assembly 428 of the oral irrigator 400. The view of FIG. 4B illustrates various elements transparently to facilitate the demonstration of various internal components. The power assembly 428 includes an inner casing 434 that contains the battery 430 and the PCB 432. The PCB 432 is electrically connected to the battery 430 and has / includes various items, including a switch 436 (e.g., a metal-oxide-semiconductor field-effect transistor (MOSFET)) configured to switch power of the battery 430 to the motor 412, a current sensing circuit 438 that generates a current measurement signal for a current through the motor, and a controller 440 that is operationally connected to the current sensing circuit and the switch. The PCB 432 may also include portions of a charging circuit that is configured to charge the battery 430.

[0055] These (and other) components included on the PCB 432 can be provided as either through-hole components and / or surface mount devices (SMDs) of the PCB 432, as the case may be.

[0056] The charging circuit used by the oral irrigator 400 further includes the discoid ferrite 446 and the inductor wire 442 that is arranged within a spiral 444 thereon and that connects back to the PCB 432, as illustrated in FIG. 4B. This arrangement provides for the charging of the battery 430 in cases where the overall power assembly 428 is located within an appropriate fluctuating magnetic field.124906-4427-8396\2Docket No. P324043.W0.01

[0057] Note that the particular charging circuit used by the oral irrigator 400 to charge the battery 430 is given by way of example (and not by way of limitation). Other oral irrigators may charge a battery in other ways, such as with inductive charging circuitry of a different physical arrangement, or by a physical attachment of the oral irrigator to a wire connected to an external power source. Further, various embodiments for oral irrigators where a battery that is depleted is user-replaceable with another, already-charged battery are contemplated.

[0058] FIG. 5 illustrates a circuit diagram 502 for circuitry of the oral irrigator 400. Among other items, the circuit diagram 502 illustrates the motor 412, the battery 430, the switch 436, and the current sensing circuit 438 of FIG. 4A and FIG. 4B in circuit element form. It will be understood that various elements of the circuit diagram 502 (other than, for example, the motor 412 and the battery 430) may be found on the PCB 432 of the oral irrigator 400.

[0059] In the illustrated configuration, the battery 430 is arranged to act as a power source of power to the motor 412 as switched by the switch 436. In the example of FIG. 5, the switch 436 is aMOSFET.

[0060] The switch 436 is switched as controlled by an MTR_EN signal 506 that is operatively connected to the switch 436 (in this case, through the resistor 530) and accordingly acts as a switch operation signal. The MTR_EN signal 506 may be a pulse width modulation (PWM) signal. Accordingly, during a portion of the MTR_EN signal 506 that is in a on state, the switch 436 is switched on, while during a second portion of the MTR EN signal 506 that is in a off state, the switch 436 is switched off. The MTR_EN signal 506 may be generated by the controller 440 (e.g., at a PWM pin 528 of the controller 440).

[0061] When the switch 436 is switched on, there is a path for current through the motor 412 through the switch 436 down through the sense resistor 504 and from there to ground. With respect to the use of a switch 436 that is a MOSFET (as particularly illustrated in FIG. 5), this the MOSFET is on when the on state of the MTR_EN signal 506 through the resistor 530 is detected at the gate, thereby enabling current to travel between the source and the drain.Alternatively, when the switch 436 is switched off, this path is not available to the circuit.

[0062] Under the illustrated arrangement, the controller 440 can control an effective voltage for the motor 412 to some value between 0 volts (V) and a present voltage of the battery 430 (inclusive) by adjusting a duty cycle of the MTR_EN signal 506. Note that the MTR_EN signal 506 signal is configured to switch the switch 436 at a rate that is well above a frequency response of the motor 412, meaning that the motor 412 perceives this effective voltage134906-4427-839612Docket No. P324043.W0.01continuously, without explicit regard to the immediately existing on or off state of the switch 436.

[0063] The current sensing circuit 438 is used to generate an I_SENSE signal 508 that represents a current through the motor 412 over time. As illustrated, this I SENSE signal 508 is provided to the controller 440 (e.g., at an analog to digital converter (ADC) pin 526 of the controller 440). The current sensing circuit 438 includes, among other items, a sense resistor 504 and an operational amplifier (op-amp) 510.

[0064] The sense resistor 504 is provided in series with the motor 412 such that the current through the motor passes through the sense resistor 504 as well, as described. (Note that the first input terminal 512 of the op-amp 510, which is illustrated as operationally connected between the switch 436 and the sense resistor 504, draws a negligible amount of this current). The opposite terminal for the sense resistor 504 is connected to ground (GND).

[0065] The sense resistor 504 is of a very low resistance (A) value (in the illustrated case, the sense resistor 504 is a 0.01 Ohm (Q) resistor). The use of such a low value of resistance gives, according to Ohm's law V = IR, where / represents current), a very small voltage over the sense resistor 504. Accordingly, the voltage across the sense resistor 504 (" ense") is a voltage-keyed representation of the current through the sense resistor 504 (which, as explained, is also the current through motor 412) that has been scaled to a usefully-small level.

[0066] As illustrated, the first input terminal 512 of the op-amp 510 is operationally connected between the motor 412 and the sense resistor 504 and correspondingly reads Vsenseas input over time. (Note that the filtering resistor 514 and the filtering capacitor 516 are used to filter this input (e.g., for high frequency noise) and do not have any steady-state effects on Vsense). An output terminal 518 of the op-amp 510 presents the I_SENSE signal 508 and is in a feedback loop with a second input terminal 520 of the op-amp 510. This feedback loop causes I_SENSE signal 508 to represent an amplified Vsense. The feedback loop is tuned (according to a first amplification tuning resistor 522 and second amplification tuning resistor 524) such that the amount of amplification applied to Vsenseby the op-amp 510 causes the resulting I_SENSE signal 508 to fall within a useful range for capture at an ADC pin 526 of the controller 440. Values for the first amplification tuning resistor 522 and the second amplification tuning resistor 524 may be selected such that the useful range is achieved.

[0067] As discussed in additional detail herein, based on the I_SENSE signal 508, the controller 440 determines an RPM of the motor 412. The controller 440 can then compare the 144906-4427-8396\2Docket No. P324043.W0.01RPM of the motor to a desired RPM. This desired RPM may correspond to a desired pulse rate for pulses of fluid from the oral irrigator 400.

[0068] If the RPM of the motor is lower than the desired RPM, the controller 440 can adjust the duty cycle of the MTR EN signal 506 as generated at the PWM pin 528 of the controller 440 to use a relatively longer on state / a relatively shorter off state. This increases the effective voltage at the motor 412, causing its RPM to increase.

[0069] If the RPM of the motor is higher than the desired RPM, the controller 440 can adjust the duty cycle of the MTR_EN signal 506 as generated at the PWM pin 528 of the controller 440 to use a relatively shorter on state / a relatively longer off state. This decreases the effective voltage at the motor 412, causing its RPM to decrease.

[0070] This mechanism may be understood as a motor current monitoring-based mechanism.

[0071] Mechanisms for determining the RPM of the motor 412 using the I SENSE signal 508 (as may be implemented by / at the controller 440) are now discussed. FIG. 6A illustrates an example waveform 602 for an I_SENSE signal 508 that represents a current through the motor 412 over time (in terms of an amplification of a voltage Vsense) as detected by the controller 440.

[0072] As illustrated, the waveform 602 is quasi-sinusoidal in nature. The pump 414 of the oral irrigator 400 is a positive displacement pump, and therefore operates according to different amounts of torque from the motor 412 during different stages of its pump cycle. As has been discussed, torque is directly proportional to current in terms of T = I • kt. Accordingly, the current used by the motor 412 (as represented within the waveform 602 of the I_SENSE signal 508) rises and falls according to the torque used to drive the pump 414 through these sequential stages during one or more pump cycles.

[0073] Accordingly, local extrema within the waveform 602 map to certain parts of certain stages of a pump cycle of the pump 414. For the oral irrigator 400, because the pump 414 is a positive displacement pump, a local maxima of the waveform 602 of the I SENSE signal 508 (such as the first local maxima 604 or the second local maxima 608) corresponds to the end of a push stroke of the piston 418, while a local minima of the waveform 602 of the I_SENSE signal 508 (such as the first local minima 606 or the second local minima 610) corresponds to the end of a vacuum stroke of the piston 418.154906-4427-8396\2Docket No. P324043.W0.01

[0074] Under such an arrangement, a duration for one full pump cycle of the pump 414 is the time between two consecutive local extrema of the same type (two consecutive local maxima or two consecutive local minima). Accordingly, the controller 440 can determine this duration by identifying, for example, the first local maxima 604 and the second local maxima 608 and subsequently subtracting the time of the first local maxima 604 from the time of the second local maxima 608 (or, alternatively by, for example, identifying the first local minima 606 and the second local minima 610 and subsequently subtracting the time of the first local minima 606 from the second local minima 610).

[0075] As also described elsewhere herein, for the oral irrigator 400, one full revolution of the drive shaft 426 of the motor 412 physically translates to one full pump cycle of the pump 414. Thus, the controller 440 understands that the duration calculated using local extrema of the waveform 602 of the I_SENSE signal 508 as just described is the duration of one full revolution of the motor 412. The controller 440 can therefore proceed to determine the RPM of the motor 412 using this duration (according to 6Q / duration (in seconds)).

[0076] Once the RPM of the motor 412 is so calculated, the controller 440 can from there proceed to adjust the PWM characteristics of the MTR_EN signal 506 that controls the switch 436 in order to increase and / or decrease the effective voltage at the motor 412, thereby driving the RPM of the motor 412 towards a desired RPM (and, correspondingly, a desired pulse rate for pulses of fluid ejected from the tip 408 of the oral irrigator 400).

[0077] Mechanisms used by the controller 440 of the oral irrigator 400 to identify local extrema (local maxima or local minima) within the waveform 602 are now explained. FIG. 6B illustrates a portion 620 of the waveform 602 near the first local maxima 604.

[0078] The controller 440 calculates derivatives between points of the waveform 602 in order to identify local extrema. For example, assume that the controller 440 has values of the I_SENSE signal 508 corresponding to each of the first-in-time point 612, the second-in-time point 614, the third-in-time point 616, and the fourth-in-time point 618 of the waveform 602, as illustrated in FIG. 6B.

[0079] First, the controller 440 subtracts the value at the second-in-time point 614 from the value of the first-in-time point 612, and accordingly arrives at a positive value for a first derivative for the portion of the waveform 602 between the first-in-time point 612 and the second-in-time point 614.164906-4427-8396\2Docket No. P324043.W0.01

[0080] Then, the controller 440 subtracts the value at the fourth-in-time point 618 from the value at the third-in-time point 616 and arrives at a negative value for a first derivative for the portion of the waveform 602 between the third-in-time point 616 and the fourth-in-time point 618.

[0081] The controller 440 accordingly concludes that there was a first derivative sign change somewhere between the second-in-time point 614 and the third-in-time point 616. Accordingly, there is a local extrema within the portion of the waveform 602 between the second-in-time point 614 and the third-in-time point 616. Note that in this case, because the first derivative sign chance went from positive to negative, the controller 440 is aware that the local extrema in question is a local maxima.

[0082] The controller 440 proceeds to identify a point between the second-in-time point 614 and the third-in-time point 616 as the first local maxima 604. Tn some cases, a value that is temporally midway between the time of the second-in-time point 614 and the time of the third-in-time point 616 is taken as the first local maxima 604. In some cases, the point between the second-in-time point 614 and the third-in-time point 616 that is taken as the first local maxima 604 is selected based on a relative weighting of the value of the second-in-time point 614 and the third-in-time point 616, where the point of the first local maxima 604 is identified closer to the one of the second-in-time point 614 and the third-in-time point 616 having the greater / higher value.

[0083] Note that analogous processes may performed by the controller 440 to identify local minima within the waveform 602, based on identifying portions of the waveform 602 for which first derivative sign changes go from negative to positive.

[0084] It will be understood that a voltage of the battery 430 of the oral irrigator 400 drops over time as current is sourced from the battery 430 to operate the oral irrigator 400. This battery voltage drop has implications for the RPM of the motor 412 over time. As is also described elsewhere herein, the effective voltage of the motor 412 (which ultimately controls the RPM of the motor) is based on some value between 0 volts (V) and a present voltage of the battery 430 (inclusive) as controlled by a present duty cycle of the MTR_EN signal 506.Accordingly, assuming an unchanged MTR_EN signal 506, as the voltage of the battery 430 drops over time, the effective voltage of the motor 412 (and thus the RPM of the motor 412) drops correspondingly.174906-4427-8396\2Docket No. P324043.W0.01

[0085] Accordingly, battery voltage monitoring-based mechanisms have been developed to account for voltage drop on the battery 430 over time such that the effective voltage of the motor 412 (and thus the RPM of the motor 412) remains steady. The controller 440 periodically calculates an average battery voltage of the battery 430. During a battery measurement period, the controller 440 takes various measurements of the battery 430 in order to determine one or more battery characteristics that apply during the battery measurement period. Such battery characteristics may include, for example, a highest battery voltage of the battery during the battery measurement period, a lowest battery voltage of the battery during the battery measurement period, etc. Then, controller 440 adjusts its generation of the MTR_EN signal 506 (e.g., adjusts a duty cycle of the MTR_EN signal 506) to operate the switch 436 to target a target effective voltage at the motor 412 based on these battery characteristics.

[0086] In some embodiments, the battery characteristics are used to determine, on a periodic basis, an average battery voltage for the corresponding battery measurement period. In one example, the highest battery voltage and the lowest battery voltage as measured during a battery measurement period are then averaged to arrive at an average battery voltage for the corresponding battery measurement period. In another example, a statistical mean of some or all measurements taken during the battery measurement period is taken as the average battery voltage for the corresponding battery measurement period.

[0087] However the average battery voltage for the battery measurement period is calculated, the controller 440 then adjusts its generation of the MTR_EN signal 506 (e.g., adjusts a duty cycle of the MTR_EN signal 506) to operate the switch 436 to target a target effective voltage at the motor 412 based on the fact that the battery 430 is currently at the calculated average battery voltage. This means that, as the voltage of the battery 430 (and thus the calculated average battery voltage) drops over time, the controller 440 correspondingly adjusts a duty cycle of the MTR EN signal 506 to use a relatively longer on state / a relatively shorter off state. This causes the effective voltage at the motor 412 (and thus RPMs of the motor 412) to remain constant (to not drop) despite the voltage drop experienced by the battery 430. In this way, the rate of pulses of fluid ejected from the tip 408 of the oral irrigator 400 remains constant even as the voltage of the battery 430 drops over time.

[0088] Note that in some embodiments, calculated average battery voltages as collected over time at the controller 440 could be processed by the controller 440 using a Kalman filter to generate a predicted current average battery voltage for a battery measurement period that is 184906-4427-8396\2Docket No. P324043.W0.01usable during that battery measurement period (e.g., in the place of average battery voltage for that battery measurement period that is based on actual measurements of the battery during that battery measurement period). Such predictions may be leveraged to reduce the number of actual measurements of the battery that are ultimately taken over time (thereby reducing power use by the controller 440).

[0089] Note that it is contemplated that the oral irrigator 400 could effectuate RPM control for the motor 412 based use of both of motor current monitoring and battery voltage monitoring as these are described herein. For example, one of these mechanisms could operate as an “outer loop mechanism" for controlling the RPM of the motor 412, while another of these mechanisms could operate as an “inner loop mechanism" for controlling the RPM of the motor 412. The inner loop mechanism may occur with a higher frequency than the outer loop mechanism.

[0090] In one example, a battery voltage monitoring-based mechanism operates as an outer loop mechanism while a motor current monitoring-based mechanism operates as an inner loop mechanism. The battery voltage monitoring-based mechanism is triggered with a certain periodicity (e.g., every 10 milliseconds (ms)), wherein once per period it is used to (re)formulate the MTR_EN signal 506 (e.g., to (re)formulate the PWM characteristics for the MTR_EN signal 506) of the oral irrigator 400. That is, once per period, the battery voltage monitoring-based mechanism may be used to formulate an MTR_EN signal 506 that is used during that period. Then, within each period (between battery voltage monitoring-based mechanism triggers), the motor current monitoring-based mechanism could be used to further adjust (tune) the MTR_EN signal 506 as necessary to keep the RPM of the motor 412 at the target RPM during that period.

[0091] This behavior could be repeated across many such periodicities. In this way, the user perceives a constant, well-controlled pulse rate with respect to pulses of fluid ejected from the tip 408 of the oral irrigator 400 over time.

[0092] The use of the battery voltage monitoring-based mechanisms and / or the motor current monitoring-based mechanisms described herein provide for robust monitoring and control of the RPM of the motor 412 (and thus a pulse rate for pulses of fluid ejected from the tip 408 of the oral irrigator 400). As is described herein, both the battery voltage monitoring-based mechanisms and / or the motor current monitoring-based mechanisms described herein for monitoring and controlling RPM of a motor 412 are implementable using a programmable controller 440 along with circuitry on / within a PCB 432. Accordingly, embodiments discussed 194906-4427-8396\2Docket No. P324043.W0.01herein avoid the need for other hardware for purposes of motor RPM monitoring, such as optical encoders, etc.

[0093] FIG. 7 illustrates a method 700 of an oral irrigator, according to embodiments discussed herein. The method 700 includes generating 702 a current measurement signal for a current through a motor of the oral irrigator from a current sensing circuit of the oral irrigator. The adjusting 704 further includes adjusting 704, based on the current measurement signal, a switch operation signal that operates a switch that switches a power source used by the oral irrigator to the motor to drive an RPM of the motor to a desired RPM that corresponds to a desired pulse rate for pulses of fluid ejected from the oral irrigator such that the pulse rate of the pulses of fluid is driven to the desired pulse rate.

[0094] In some embodiments, the method 700 further includes calculating the RPM of the motor based on the current measurement signal, and the adjusting the switch operation signal to drive the RPM of the motor to the desired RPM is based on the RPM of the motor as calculated by the controller using the current measurement signal. In some such embodiments, the RPM of the motor is calculated based on the current measurement signal by: identifying a first time corresponding to a first local extrema within the current measurement signal and a second time corresponding to a second local extrema within the current measurement signal; determining a periodicity of the current measurement signal based on the first time and the second time; and correlating the periodicity of the current measurement signal to the RPM of the motor.

[0095] In some embodiments of the method 700, the switch operation signal is adjusted by adjusting a PWM duty cycle of the switch operation signal.

[0096] In some embodiments of the method 700, the current sensing circuit comprises: a sense resistor that is in series with the motor and through which the current through the motor travels; and an operational amplifier comprising: a first input terminal that is operationally connected between the motor and the sense resistor; an output terminal at which the current measurement signal is generated; and a second input terminal that is in a feedback loop with the output terminal that is tuned to cause the current measurement signal to fall within a voltage range usable by a controller of the oral irrigator.

[0097] In some embodiments of the method 700, the switch comprises a MOSFET.

[0098] FIG. 8 illustrates a method 800 of an oral irrigator, according to embodiments discussed herein. The method 800 includes measuring 802 a battery of the oral irrigator during a first battery measurement period to determine one or more first battery characteristics of the 204906-4427-8396\2Docket No. P324043.W0.01battery during the first battery measurement period. The method 800 further includes formulating 804, based on the one or more first battery characteristics, a switch operation signal that operates a switch that switches the battery to a motor of the oral irrigator to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, a target effective voltage at the motor.

[0099] In some embodiments of the method 800, the one or more first battery characteristics comprises each of a first highest battery voltage of the battery and a first lowest battery voltage of the battery during the first battery measurement period; the method 800 further includes calculating a first average battery voltage using the first highest battery voltage and the first lowest battery voltage; and the formulation of the switch operation signal is based on the first average battery voltage calculated using the first highest battery voltage and the first lowest battery voltage.

[0100] In some embodiments, the method 800 further includes measuring the battery during a second battery measurement period to determine one or more second battery characteristics of the battery during the second battery measurement period; and reformulating, based on the one or more second battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, the target effective voltage at the motor. In some such embodiments, the one or more second battery characteristics comprises each of a second highest battery voltage of the battery and a second lowest battery voltage of the battery during the second battery measurement period; the method 800 further includes calculating a second average battery voltage using the second highest battery voltage and the second lowest battery voltage that is different than a first average battery voltage during the first battery measurement period; and the reformulation of the switch operation signal is based on the second average battery voltage calculated using the second highest battery voltage and the second lowest battery voltage.

[0101] In some embodiments of the method 800, the switch operation signal is formulated by establishing a PWM duty cycle of the switch operation signal.

[0102] In some embodiments of the method 800, the switch comprises a MOSFET.

[0103] FIG. 9 illustrates a method 900 of an oral irrigator, according to embodiments discussed herein. The method 900 includes measuring 902 a battery used by the oral irrigator during a first battery measurement period to determine one or more first battery characteristics of the battery during the first battery measurement period. The method 900 further includes 214906-4427-8396\2Docket No. P324043.W0.01formulating 904, based on the one or more first battery characteristics, a switch operation signal to target, based on a switching of the battery to a motor of the oral irrigator by a switch of the oral irrigator that is controlled by the switch operation signal, a target effective voltage at the motor. The method 900 further includes adjusting 906, based on a current measurement signal for a current through the motor generated by a current sensing circuit of the oral irrigator, the switch operation signal to drive an RPM of the motor to a desired RPM that corresponds to a desired pulse rate for pulses of fluid ejected from the oral irrigator such that a pulse rate of the pulses of fluid is driven to the desired pulse rate.

[0104] In some embodiments, the method 900 further includes calculating the RPM of the motor based on the current measurement signal, and wherein the adjusting the switch operation signal to drive the RPM of the motor to the desired RPM is based on the RPM of the motor as calculated by the controller using the current measurement signal. In some such embodiments, the RPM of the motor is calculated based on the current measurement signal by: identifying a first time corresponding to a first local extrema within the current measurement signal and a second time corresponding to a second local extrema within the current measurement signal; determining a periodicity of the current measurement signal based on the first time and the second time; and correlating the periodicity of the current measurement signal to the RPM of the motor.

[0105] In some embodiments of the method 900, the one or more first battery characteristics comprises each of a first highest battery voltage of the battery and a first lowest battery voltage of the battery during the first battery measurement period; the controller calculates a first average battery voltage using the first highest battery voltage and the first lowest battery voltage; and the formulation of the switch operation signal is based on the first average battery voltage calculated using the first highest battery voltage and the first lowest battery voltage.

[0106] In some embodiments, the method 900 further includes, measuring the battery during a second battery measurement period to determine one or more second battery characteristics of the battery during the second battery measurement period; and reformulating, based on the one or more second battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, the target effective voltage at the motor. In some such embodiments, the one or more second battery characteristics comprises each of a second highest battery voltage of the battery and a second lowest battery voltage of the battery during the second battery measurement period; the 224906-4427-8396\2Docket No. P324043.W0.01controller calculates a second average battery voltage using the second highest battery voltage and the second lowest battery voltage that is different than a first average battery voltage during the first battery measurement period; and the reformulation of the switch operation signal is based on the second average battery voltage calculated using the second highest battery voltage and the second lowest battery voltage.

[0107] In some embodiments of the method 900, the switch operation signal is formulated by establishing a PWM duty cycle of the switch operation signal.

[0108] In some embodiments of the method 900, the switch operation signal is adjusted by adjusting a PWM duty cycle of the switch operation signal.

[0109] In some embodiments of the method 900, the current sensing circuit comprises: a sense resistor that is in series with the motor and through which the current through the motor travels; and an operational amplifier comprising: a first input terminal that is operationally connected between the motor and the sense resistor; an output terminal at which the current measurement signal is generated; and a second input terminal that is in a feedback loop with the output terminal that is tuned to cause the current measurement signal to fall within a voltage range usable by a controller of the oral irrigator.

[0110] In some embodiments of the method 900, the switch comprises a MOSFET.[OHl] This description is not intended to be limited to the forms disclosed herein.Consequently, variations and modifications commensurate with the teachings, skills and knowledge of the relevant art are within the scope of the present disclosure.

[0112] It should be noted that any of the features in the various examples and embodiments provided herein may be interchangeable and / or replaceable with any other example or embodiment. As such, the discussion of any component or element with respect to a particular example or embodiment is meant as illustrative only. It should be noted that although the various examples discussed herein have been discussed with respect to oral care devices such as oral irrigators, the devices and techniques may be applied in a variety of applications, such as, but not limited to, other oral care devices such as toothbrushes, bath appliances, or the like.

[0113] All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the examples of the invention, and do not create limitations, particularly as to the position, orientation, or use of the invention unless specifically set forth in the claims. Joinder references (e g., attached,234906-4427-8396\2Docket No. P324043.W0.01coupled, connected, joined, affixed, and the like) are to be construed broadly and may include intermediate members between the connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

[0114] In some instances, components are described by reference to “ends” having a particular characteristic and / or being connected with another part. However, those skilled in the art will recognize that the present invention is not limited to components which terminate immediately beyond their point of connection with other parts. Thus the term “end” should be broadly interpreted, in a manner that includes areas adjacent rearward, forward of or otherwise near the terminus of a particular element, link, component, part, member or the like. In methodologies directly or indirectly set forth herein, various steps and operations are described in one possible order of operation but those skilled in the art will recognize the steps and operation may be rearranged, replaced or eliminated without necessarily departing from the spirit and scope of the present invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting.Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.244906-4427-8396\2

Claims

Docket No. P324043.W0.01CLAIMS1. An oral irrigator, comprising:a pump configured to eject pulses of fluid from the oral irrigator,a motor operably connected to the pump, wherein a pulse rate of the pulses of fluid ejected from the oral irrigator by the pump corresponds to a revolutions per minute (RPM) of the motor;a switch that switches a power source used by the oral irrigator to the motor;a current sensing circuit that generates a current measurement signal for a current through the motor; anda controller connected to the current sensing circuit and that generates a switch operation signal that operates the switch, wherein the controller:receives the current measurement signal from the current sensing circuit; and adjusts, based on the current measurement signal, the switch operation signal to drive the RPM of the motor to a desired RPM that corresponds to a desired pulse rate for the pulses of fluid such that the pulse rate of the pulses of fluid is driven to the desired pulse rate.

2. The oral irrigator of claim 1, wherein the controller further calculates the RPM of the motor based on the current measurement signal, and wherein the adjusting the switch operation signal to drive the RPM of the motor to the desired RPM is based on the RPM of the motor as calculated by the controller using the current measurement signal.

3. The oral irrigator of claim 2, wherein the controller calculates the RPM of the motor based on the current measurement signal by:identifying a first time corresponding to a first local extrema within the current measurement signal and a second time corresponding to a second local extrema within the current measurement signal;determining a periodicity of the current measurement signal based on the first time and the second time; andcorrelating the periodicity of the current measurement signal to the RPM of the motor.

4. The oral irrigator of claim 1, wherein the controller adjusts the switch operation signal by adjusting a pulse width modulation (PWM) duty cycle of the switch operation signal.254906-4427-8396\2Docket No. P324043.W0.

015. The oral irrigator of claim 1, wherein the power source comprises a battery; and wherein the controller further:measures the battery during a battery measurement period to determine one or more battery characteristics of the battery during the battery measurement period; and formulates, based on the one or more battery characteristics, the switch operation signal to target, based on the switching of the power source to the motor by the switch as controlled by the switch operation signal, a target effective voltage at the motor; wherein the switch operation signal is so formulated before the controller adjusts the switch operation signal based on the RPM of the motor.

6. The oral irrigator of claim 5, wherein:the one or more battery characteristics comprises each of a highest battery voltage of the battery and a lowest battery voltage of the battery during the battery measurement period; the controller calculates an average battery voltage using the highest battery voltage and the lowest battery voltage; andthe formulation of the switch operation signal is based on the average battery voltage calculated using the highest battery voltage and the lowest battery voltage.

7. The oral irrigator of claim 5, wherein the controller formulates the switch operation signal by establishing a pulse width modulation (PWM) duty cycle of the switch operation signal.

8. The oral irrigator of claim 1, wherein the current sensing circuit comprises:a sense resistor that is in series with the motor and through which the current through the motor travels; andan operational amplifier having:a first input terminal that is operationally connected between the motor and the sense resistor:an output terminal at which the current measurement signal is generated; and a second input terminal that is in a feedback loop with the output terminal that is tuned to cause the current measurement signal to fall within a voltage range usable by a controller of the oral irrigator.

9. The oral irrigator of any of claim 1 to claim 8, wherein the switch comprises a metal-oxide-semiconductor field-effect transistor (MOSFET).264906-4427-8396\2Docket No. P324043.W0.0110. An oral irrigator, comprising:a pump configured to eject pulses of fluid from the oral irrigator,a motor operably connected to the pump;a switch that switches a battery used by the oral irrigator to the motor; anda controller that generates a switch operation signal that operates the switch, wherein the controller:measures the battery during a first battery measurement period to determine one or more first battery characteristics of the battery during the first battery measurement period; andformulates, based on the one or more first battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, a target effective voltage at the motor.

11. The oral irrigator of claim 10, wherein:the one or more first battery characteristics comprises each of a first highest battery voltage of the battery and a first lowest battery voltage of the battery during the first battery measurement period;the controller calculates a first average battery voltage using the first highest battery voltage and the first lowest battery voltage; andthe formulation of the switch operation signal is based on the first average battery voltage calculated using the first highest battery voltage and the first lowest battery voltage.

12. The oral irrigator of claim 10, wherein the controller further:measures the battery during a second battery measurement period to determine one or more second battery characteristics of the battery during the second battery measurement period; andreformulates, based on the one or more second battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, the target effective voltage at the motor.

13. The oral irrigator of claim 12, wherein:274906-4427-8396\2Docket No. P324043.W0.01the one or more second battery characteristics comprises each of a second highest battery voltage of the battery and a second lowest battery voltage of the battery during the second battery measurement period;the controller calculates a second average battery voltage using the second highest battery voltage and the second lowest battery voltage, wherein the second average battery voltage is different than a first average battery voltage calculated by the controller during the first battery measurement period; andthe reformulation of the switch operation signal is based on the second average battery voltage calculated using the second highest battery voltage and the second lowest battery voltage.

14. The oral irrigator of claim 10, wherein the controller formulates the switch operation signal by establishing a pulse width modulation (PWM) duty cycle of the switch operation signal.

15. The oral irrigator of claim 10, further comprising adjusting the switch operation signal to drive a revolutions per minute (RPM) of the motor to a desired RPM corresponding to a desired pulse rate for the pulses of fluid, wherein the switch operation signal is so adjusted after the controller formulates the switch operation signal based on the first average battery voltage.

16. The oral irrigator of claim 15, wherein the controller adjusts the switch operation signal by adjusting a pulse width modulation (PWM) duty cycle of the switch operation signal.

17. The oral irrigator of any of claim 10 to claim 16, wherein the switch comprises a metal-oxide-semiconductor field-effect transistor (MOSFET).

18. A method of an oral irrigator, comprising:measuring a battery used by the oral irrigator during a first battery measurement period to determine one or more first battery characteristics of the battery during the first battery measurement period;formulating, based on the one or more first battery characteristics, a switch operation signal to target, based on a switching of the battery to a motor of the oral irrigator by a switch of the oral irrigator that is controlled by the switch operation signal, a target effective voltage at the motor; andadjusting, based on a current measurement signal for a current through the motor generated by a current sensing circuit of the oral irrigator, the switch operation signal to drive a 284906-4427-8396\2Docket No. P324043.W0.01revolutions per minute (RPM) of the motor to a desired RPM that corresponds to a desired pulse rate for pulses of fluid ejected from the oral irrigator such that a pulse rate of the pulses of fluid is driven to the desired pulse rate.

19. The method of claim 18, further comprising calculating the RPM of the motor based on the current measurement signal, and wherein the adjusting the switch operation signal to drive the RPM of the motor to the desired RPM is based on the RPM of the motor as calculated by the controller using the current measurement signal.

20. The method of claim 19, wherein the RPM of the motor is calculated based on the current measurement signal by:identifying a first time corresponding to a first local extrema within the current measurement signal and a second time corresponding to a second local extrema within the current measurement signal;determining a periodicity of the current measurement signal based on the first time and the second time; andcorrelating the periodicity of the current measurement signal to the RPM of the motor.

21. The method of claim 18, wherein:the one or more first battery characteristics comprises each of a first highest battery voltage of the battery and a first lowest battery voltage of the battery during the first battery measurement period;the controller calculates a first average battery voltage using the first highest battery voltage and the first lowest battery voltage; andthe formulation of the switch operation signal is based on the first average battery voltage calculated using the first highest battery voltage and the first lowest battery voltage.

22. The method of claim 18, further comprising:measuring the battery during a second battery measurement period to determine one or more second battery characteristics of the battery during the second battery measurement period; andreformulating, based on the one or more second battery characteristics, the switch operation signal to target, based on the switching of the battery to the motor by the switch as controlled by the switch operation signal, the target effective voltage at the motor.294906-4427-8396\2Docket No. P324043.W0.0123. The method of claim 22, wherein:the one or more second battery characteristics comprises each of a second highest battery voltage of the battery and a second lowest battery voltage of the battery during the second battery measurement period;the controller calculates a second average battery voltage using the second highest battery voltage and the second lowest battery voltage that is different than a first average battery voltage during the first battery measurement period; andthe reformulation of the switch operation signal is based on the second average battery voltage calculated using the second highest battery voltage and the second lowest battery voltage.

24. The method of any of claim 18, wherein the switch operation signal is formulated by establishing a pulse width modulation (PWM) duty cycle of the switch operation signal.

25. The method of any of claim 18, wherein the switch operation signal is adjusted by adjusting a pulse width modulation (PWM) duty cycle of the switch operation signal.

26. The method of claim 18, wherein the current sensing circuit comprises:a sense resistor that is in series with the motor and through which the current through the motor travels; andan operational amplifier comprising:a first input terminal that is operationally connected between the motor and the sense resistor;an output terminal at which the current measurement signal is generated; and a second input terminal that is in a feedback loop with the output terminal that is tuned to cause the current measurement signal to fall within a voltage range usable by a controller of the oral irrigator.

27. The method of claim 18, wherein the switch comprises a metal-oxide-semiconductor fieldeffect transistor (MOSFET).304906-4427-8396\2

Images