WO2015051248A1 - Battery compensation system using pwm - Google Patents

Battery compensation system using pwm Download PDF

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Publication number
WO2015051248A1
WO2015051248A1 PCT/US2014/059040 US2014059040W WO2015051248A1 WO 2015051248 A1 WO2015051248 A1 WO 2015051248A1 US 2014059040 W US2014059040 W US 2014059040W WO 2015051248 A1 WO2015051248 A1 WO 2015051248A1
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WO
WIPO (PCT)
Prior art keywords
battery
pwm
voltage
user
power
Prior art date
Application number
PCT/US2014/059040
Other languages
English (en)
French (fr)
Inventor
Jack C. Cornelius
Vincent O'malley
Original Assignee
Abominable Labs, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/046,969 external-priority patent/US9419520B2/en
Application filed by Abominable Labs, Llc filed Critical Abominable Labs, Llc
Priority to KR1020167011997A priority Critical patent/KR20160066042A/ko
Priority to EP14850350.1A priority patent/EP3053260A4/en
Priority to CA2925348A priority patent/CA2925348A1/en
Priority to JP2016520014A priority patent/JP6563387B2/ja
Priority to AU2014329396A priority patent/AU2014329396B2/en
Priority to CN201480055014.1A priority patent/CN105684284A/zh
Publication of WO2015051248A1 publication Critical patent/WO2015051248A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0006—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation
    • G—PHYSICS
    • G02—OPTICS
    • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C11/00—Non-optical adjuncts; Attachment thereof
    • G02C11/08—Anti-misting means, e.g. ventilating, heating; Wipers
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
    • G06F13/38—Information transfer, e.g. on bus
    • G06F13/382—Information transfer, e.g. on bus using universal interface adapter
    • G06F13/385—Information transfer, e.g. on bus using universal interface adapter for adaptation of a particular data processing system to different peripheral devices
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
    • G06F13/38—Information transfer, e.g. on bus
    • G06F13/40—Bus structure
    • G06F13/4063—Device-to-bus coupling
    • G06F13/4068—Electrical coupling
    • G06F13/4081—Live connection to bus, e.g. hot-plugging
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/1563—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators without using an external clock
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0227—Applications
    • H05B1/023—Industrial applications
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
    • H02M1/0022—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters the disturbance parameters being input voltage fluctuations
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/011—Heaters using laterally extending conductive material as connecting means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/013—Heaters using resistive films or coatings

Definitions

  • This invention relates to regulating power from a battery to drive a load, and more particularly to compensating for a decrease in voltage from a Lithium-Ion battery as it dissipates over time in use to consistently power a portable electronic device.
  • Lithium-Ion battery technology in many more such devices to provide power to provide power to them them, except that a known issue with Lithium- Ion batteries is the fact that, as their charge decreases over time in use, the voltage output they provide also decreases over time in use.
  • a common characteristic of such portable devices is the fact that they are light weight enough to be carried on a user's body, e.g., worn on a user's head.
  • Examples of fog-prone sport goggles intended for use during winter activities have included goggles for downhill skiing, crosscountry skiing, snowboarding, snowmobiling, sledding, tubing, ice climbing and the like, and are widely known and widely utilized by sports enthusiasts and others whose duties or activities require them to be outside in snowy and other inclement cold weather conditions.
  • Examples of fog-prone dive masks have included eye and nose masks independent of a breathing apparatus as well as full- face masks in which the breathing apparatus is integrated into the mask.
  • fog-prone eye-protecting shields have included a face shield that a doctor or dentist would wear to prevent pathogens from getting into the user's mouth or eyes, or a transparent face shield portion of a motorcycle helmet. Fogging that impairs vision is a common problem with such goggles, dive masks and eye-protecting shields.
  • Examples of hand-held devices that require consistent power to heat the displays of such devices to prevent fogging of the display have included hand-held GPS units, radios, telephones, medical devices (EKG readouts), readers, tablets, portable computers, point of sale terminals, etc.
  • PWM pulse-width modulation
  • Manual switching of power to an eye shield or other hand-held device doesn't allow the user to set an intermediate heat value that is sufficient to curtail fogging or otherwise heat but which also conserves battery life. Further, there are no known systems disclosed in the prior art for balanced heating of a film or other resistive element on an eye shield or hand-held screen, while compensating to provide consistent power despite battery depletion, which also provide variable control of a heating element on the device.
  • an eye-shield condensation preventing system comprising: an eye shield adapted for protecting a user's eyes and adapted for defining at least a partially enclosed space between the user's eyes and the eye shield, a power source, a pulse-width modulator (PWM), a switching means responsive to the pulse-width modulator, a heating element on the eye shield, and a circuit interconnecting the power source, the pulse-width modulator, the switching means and the heating element for controlling heating of the eye shield.
  • the switching means comprises a metal-oxide-semiconductor field-effect transistor.
  • the device of this aspect of the invention provides a single-PWM, single heating region eye shield fog prevention device that enables efficient heating of the eye shield or lens so that battery life is maximized, since PWM can be preset to an output having a percentage ratio of on to off cycles that is tailored specifically to the particular goggle lens to which power is being applied.
  • an eye-shield condensation preventing system comprising: an irregular-shaped eye shield comprising a surface area divisible into a plurality of regions of one or more sizes to facilitate divisible heating of the eye- shield, the eye shield being adapted for protecting a user's eyes and adapted for defining at least a partially enclosed space between the user's eyes and the shield.
  • the system further comprises a power source, a plurality of PWMs, each PWM operatively connected with the power source and a plurality of switching means, each switching means responsive to a corresponding PWM.
  • each the heating element there are a plurality of heating elements on the eye-shield, each the heating element extending to a corresponding size region of the eye-shield, and a plurality of circuits, each the circuit interconnecting one of the PWMs with a corresponding one of the switching means and one of the corresponding heating elements.
  • Each the PWM produces a duty cycle for providing an amount of current to the corresponding heating element such that the power output of each region of the eye shield corresponds to a desired output for the region of the eye shield.
  • an eye-shield condensation preventing system comprising : an eye-shield adapted for protecting a user's eyes and adapted for defining at least a partially enclosed space between the user's eyes and the eye shield, the eye shield having a surface area divisible into at least one region for facilitating region heating of the eye-shield to a desired temperature, a power source, at least one PWM, at least one heating element on and corresponding with the at least one region for facilitating region heating of the eye shield, the at least one heating element corresponding with the at least one PWM.
  • the device of the multiple-region aspect of the invention provides a multiple-PWM resistive film heating system on the eye shield or lens surface that is divided into multiple regions, for example regions according to irregular and differently-shaped portions of the lens such as directly over the bridge of the nose as compared to directly in front of the eyes, to enable even heating of differently-shaped or sized regions.
  • the regions may be used to divide the lens into a plurality of regions, each of similar area from one region to the next, to enable more even heating across the eye shield.
  • this division may be used to allow specific heating of a certain area of the eye shield, for example to ensure proper function of an electronic display portion of the lens.
  • the PWMs may be operated in accordance with a profile such that the power per square unit, i.e., power density, of each region of the eye shield may be assured to be substantially equal and evenly distributed across the region regardless of the size of each region.
  • heating of the regions may be independently adjusted to create a specific profile desired for a particular eye shield to account for various pre-determined weather conditions, various activities or eye shield types, shapes and sizes.
  • the plurality of PWMs of this aspect of the invention comprises a microcomputer capable of simultaneously performing a plurality of various internal PWM functions corresponding to the plurality of PWMs, the microcomputer having a plurality of I/O ports for interconnecting the internal PWM functions with the plurality of circuits.
  • each of the switching means in accordance with this aspect of the invention comprises a metal-oxide- semiconductor field-effect transistor (MOSFET).
  • MOSFET metal-oxide- semiconductor field-effect transistor
  • an eye-shield condensation preventing system as previously summarized which further comprises a current adjustment means (CAM) operatively connected to each PWM (whether a single-PWM embodiment or a multiple PWM embodiment) for varying duty cycle of the power source via each PWM in turn varying the amount of current delivered to each heating element.
  • CAM current adjustment means
  • the device of this aspect of the invention provides the ability of the CAM for efficient managing of the temperature of the eye shield lens at a temperature that is just above the dew point temperature to effectively prevent fogging with a minimum of attention by the user. This, in turn, allows power savings to enable longer battery life.
  • an eye-shield condensation preventing system as previously described, whether a multiple-region, multiple-PWM embodiment, or a single-region, single-PWM embodiment, the device further comprising means for measuring ambient temperature and relative humidity and means for calculating dew point.
  • the means for calculating dew point in this aspect of the invention is preferably operatively connected with the CAM (preferably further comprising microcomputer means) such that the CAM increases power to the electrical circuit when temperature within the space by the eye shield falls below the dew point temperature threshold and reduces power to the electrical circuit when temperature within the space defined by the eye shield climbs above the dew point temperature threshold.
  • the invention is capable of feeding a pulse to the resistive heating element, e.g., the film heating element, that is just enough to keep it at just above the dew point to effectively and automatically prevent fogging and to conserve battery life.
  • the means for calculating dew point preferably comprises microcomputer means operatively connected with the temperature and relative humidity sensing means.
  • the eye-shield condensation preventing system of this aspect of the invention may further comprise a relative humidity sensor and a temperature sensor, each sensor located within the space defined by the eye shield.
  • a system further comprises means, for example microcomputer means, operatively connected with the relative humidity and temperature sensor for periodically calculating dew point temperature.
  • the at least one pulse-width modulator is responsive to the means for periodically calculating dew point temperature to control the at least one heating element such that the at least one heating element is maintained at a temperature at above dew point to assure prevention of fogging over time.
  • the eye-shield condensation preventing system of the previous two aspects of the invention may further comprise region profiling logic enabling a single adjustment from the variable current adjustment mechanism to affect proportional adjustments to each region relative to other regions.
  • the invention provides varying coordinated duty cycles to power multiple resistive regions of an eye shield for the purpose of distributing heating evenly throughout the entire eye shield by adjusting the power delivered to each segment based on a profile of the eye shield.
  • the device of this aspect of the invention provides automated profile characteristics incorporated into the fog prevention system such that desired heating of the lens, whether it be even heating across multiple regions across the entire lens, or a pre-determined specific heating pattern, or heating footprint using different regions of the lens, may be maintained upon manual, or automated, adjustment of the heating power directed to the lens.
  • an eye-shield condensation preventing system as described above in the single-region or the multiple-region aspects of the invention as described above, and further in accordance with the previous aspect of the invention comprising a plurality of predetermined data profiles and corresponding selection means enabling control of each region of the eye shield in accordance with a user-selected one of the data profiles.
  • the device of this aspect of the invention provides selectable profile characteristics incorporated into the eye shield fog preventing system such that appropriate heating may be selected by the user depending upon weather and activity level conditions, or eye-shield features employed, such as video recording, heads-up display, global positioning system, etc.
  • Each of the eye shields disclosed herein are adapted for protecting a user's eyes from wind, debris, snow, rain, extreme temperatures and elements which could harm the eyes or otherwise impair vision.
  • Each eye shield is also adapted to form and define at least a partial enclosure around and in front of the eyes. This enclosure warms up relative to conditions outside of the enclosure as a result of body heat transmitted into the space defined by the eye shield, and the enclosure also experiences higher relative humidity compared to outside conditions as a result of perspiration.
  • the temperature of the eye shield drops below the temperature within the eye shield at which dew, or condensation, would form on the inside of the eye shield, fogging of the eye shield occurs.
  • One purpose of the present invention is to provide an eye shield fog prevention system that effectively prevents the eye shield from fogging, regardless of weather conditions.
  • Another purpose of the present invention is to provide an eye shield fog prevention system that employs PWM in such a way that power and energy are conserved and battery life is extended.
  • Another purpose of the invention is to provide an eye shield fog prevention system that adjusts the power to the heater on the lens in accordance with current dew point conditions, either manually, or automatically, increases power to the eye shield as temperature within the eye shield is less than or falls below the dew point temperature, or so decreases power when temperature within the eye shield is above the dew point temperature.
  • Another purpose of the present invention is to provide an eye shield fog preventing system that assures and simplifies the attainment of fog-free usage in varying weather and activity conditions, with a plurality of different sized and shaped eye shields, by providing profiles that at least partially automate heating of the eye-shield.
  • Yet another purpose of the invention is to provide such profiles that are user selectable.
  • the shield condensation preventing system of any of the foregoing aspects of the invention may be adapted for use for heating in an anti-fog sport goggle or any protective eye- shield, such as for skiing, inner-tubing, tobogganing, ice-climbing, snow-mobile riding, cycling, running, working with patients, in other medical or testing environments, and the like. Further, the system of any of the foregoing aspects of the invention may be adapted for use in a diving mask.
  • a compensation system adapted for use with any of the foregoing battery-powered, PWM-driven eye shields, or other portable electronic device, to enable consistent power to the device load despite battery voltage drop resulting from battery depletion.
  • the compensation system in accordance with this aspect of the invention comprises: a voltage divider circuit for proportionally adjusting the voltage to a measurable range; an analog to digital converter for receiving the output from the voltage divider and converting it into a digital voltage value; and means for receiving digital voltage input and user-determined power setting input for determining a compensating duty cycle for application to the PWM to drive the load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • the voltage divider circuit of an embodiment in accordance with this aspect of the invention comprises two precision resistors in series between positive and negative terminals of the battery for proportionally adjusting the voltage to a measurable range, the voltage divider circuit preferably having a tap between the two resistors adapted to provide the proportional voltage measurement to an I/O pin on an analog-to- digital converter.
  • the user-determined, or provided, power setting for this and another aspect of the invention comprises a power level setting set by a dial, a knob, or a push button system, together with some form of visual feedback to the user to further enable selection of the setting.
  • mode switching means for user selection of battery conservation mode or consistent power output mode.
  • the battery conservation mode provides an off switch for the compensation system, whereas the consistent power mode provides an on switch for the compensation system.
  • the battery conservation mode uses less battery power than the consistent power mode, for those times where there is sufficient battery power to use the consistent power mode, it may be preferable to a user to do so, since a user-determined power level in this latter mode would yield results consistent with what a user would expect with an otherwise fully-charged battery.
  • the selection of battery conservation mode or consistent power mode depends upon the total battery charge available, the longevity of a particular battery as experienced by the user, and the anticipated level of heating required for a number of use hours anticipated by the user.
  • the battery compensation system is adapted for use with at least one lithium-ion battery-powered, PWM-driven portable electronic device.
  • a portable device may include an anti-fog eye shield, such as for example a ski goggle, a diving mask, a motorcycle or snowmobile helmet visor, or a medical or testing visor.
  • an anti-fog eye shield such as for example a ski goggle, a diving mask, a motorcycle or snowmobile helmet visor, or a medical or testing visor.
  • such a portable device may include a hand-held GPS unit, a hand-held radio, or a cell phone.
  • the compensation system of the invention further comprises a metal-oxide- semiconductor field-effect transistor switching means responsive to the pulse-width modulator. Further, in accordance with an embodiment of the invention, the compensation system of the invention further comprises current adjustment means operatively connected to the pulse-width modulator for varying duty cycle of the power source via the pulse-width modulator in turn varying the mount of current delivered to the load.
  • the means for receiving voltage input and user-determined power setting input for determining compensating duty cycle comprises a microprocessing unit for receiving voltage input and user-determined power setting input and executing software code to determine a compensating duty cycle for application by the software to the PWM to drive the load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • the microprocessing unit is preferably a battery-powered microprocessing unit. It will be appreciated by those of ordinary skill in the art that readily-available microprocessing units having on-board analog- to-digital conversion means may be used for the present invention.
  • determination of a compensating duty cycle may comprise a data lookup table of PWM duty cycle values organized according to power setting and battery depletion voltage drop and for use by the code steps run by the microprocessor to select a compensating duty cycle for application to the PWM to drive the load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • This embodiment of the invention including a lookup table provides generally faster operation and is easier to code than using floating-point calculations, though it will be appreciated that either may be used to implement the invention in accordance with its true spirit and scope.
  • a discrete logic circuit could be used to perform the functions of the compensation system of the invention, such would likely be unduly expensive to implement and no more effective than the software and data table lookup functions that are preferred for the invention.
  • the software steps themselves may be used to calculate a compensating duty cycle for application to the PWM to drive the load consistently at the user- determined power setting despite decrease in battery voltage resulting from battery depletion.
  • the formula for determining the compensating duty cycle for this embodiment of the invention which is the same formula used to determine data table duty cycle values (from user input power settings and measured voltage) used in a previous software embodiment is as follows:
  • the compensation system in accordance with this aspect of the invention enables maintenance of a user-selected and/or desired power setting to drive a load to consistently heat a portable device, such as anti-fog goggles or a hand-held GPS, radio or phone, despite partial depletion of a device battery, as long as there is sufficient battery charge to maintain the system- compensated power output.
  • a portable device such as anti-fog goggles or a hand-held GPS, radio or phone
  • an alternative embodiment compensation system adapted for use with a battery-powered, multi-channel PWM- driven portable electronic device having a plurality of loads corresponding to each PWM channel to enable consistent power to each of the loads of the device despite battery voltage drop resulting from battery depletion.
  • the compensation system in accordance with this aspect of the invention comprises: a voltage divider circuit for proportionally adjusting the voltage to a measurable range; an analog to digital converter for receiving the output from the voltage divider and converting it into a digital voltage value; and a microprocessing unit for running software code steps for receiving digital voltage input and user-determined power setting input for each load for determining a compensating duty cycle for application by the software to each PWM channel to drive each corresponding load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • the compensation system in accordance with this aspect of the invention enables compensation for a depleting battery source for maintaining, with the use of a multi-channel PWM system, consistent power over time to each of a plurality of loads of a portable device (as long as there remains sufficient battery charge to power the device), such as a multi-region, anti-fog eye shield powered by the system to evenly heat each of the regions across the eye shield to a consistent temperature.
  • a system in accordance with this aspect of the invention may be used to provide consistent heating, despite battery depletion over time, to heat a multi- heating-element-region eye shield to prevent fogging in each of the regions according to a custom heating profile applied to the eye shield.
  • each of the plurality of loads comprises a heating element region on an eye shield and each corresponding PWM channel is for providing the same power density to each heating element region for even heating across the entire eye shield.
  • This even heating embodiment of the invention further preferably comprises a data lookup table of PWM duty cycle values organized according to power setting and battery depletion voltage drop and for use by the code steps to select a compensating duty cycle for application to each PWM to drive each load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • each of the plurality of loads comprises a heating element region on an eye shield and each corresponding PWM channel is for providing a power density to each heating element region in accordance with the custom heating profile across the eye shield.
  • This custom heating embodiment further comprises a plurality of data lookup tables of PWM duty cycle values, one data lookup table for each different power density specified by the custom heating profile, each data table being organized according to power setting and battery depletion voltage drop and for use by the code steps to select a compensating duty cycle for application to each PWM to drive each load consistently at the corresponding power setting despite decrease in battery voltage resulting from battery depletion.
  • Each of the aspects of the invention provides for consistent power to the load of a portable electronic device, despite charge/ or power, depletion or dissipation of the battery over time in use.
  • these aspects of the invention provide a consistent feedback to the user who is reinforced and supported in coming to expect that a certain power setting on the device, selected from a series of power settings such as 2 Watts, 4 Watts, 6 Watts, 8 Watts or 10 Watts, will effectively heat the portable device at the desired power level during anticipated weather conditions.
  • the compensation system of the invention whether single-channel PWM or multichannel PWM embodiments of the invention, further preferably comprises a data lookup table of PWM duty cycle values organized according to power setting and battery depletion voltage drop and for use by the code steps to select a compensating duty cycle for application to the PWM to drive the load consistently at the user-determined power setting despite decrease in battery voltage resulting from battery depletion.
  • FIG. 1 is a graphic representation of a plurality of electrical signals emanating from a pulse-width modulator (PWM);
  • PWM pulse-width modulator
  • FIG. 2 is a front plan view schematic representation of an irregular-shaped eye shield having a single-region, resistive heating element film heater thereon;
  • FIG. 3 is a front plan view schematic representation of an irregular-shaped eye shield having a resistive heating element film heater thereon that is divided into a plurality of regions;
  • FIG. 4 is a front plan view schematic representation of an irregular-shaped eye shield having a resistive heating element film heater thereon that is divided into a plurality of regions;
  • FIG. 5 is a schematic representation of a single-PWM, single-region eye shield fog prevention system in accordance with an aspect of the invention
  • FIG. 6 is a schematic representation of a single-PWM, single-region eye shield fog prevention system in accordance with an aspect of the invention
  • FIG. 7 is a schematic representation of another embodiment of a single-PWM, single- region eye shield fog prevention system in accordance with an aspect of the invention.
  • FIG. 8 is a schematic representation of yet another embodiment of an automated single-PWM, single-region eye shield fog prevention system in accordance with another aspect of the invention.
  • FIG. 9 is a schematic representation of still another embodiment of a multiple-PWM, multiple-region eye shield fog prevention system in accordance with another aspect of the invention.
  • FIG. 10 is a schematic representation of another embodiment of an automated multiple-PWM, multiple-region eye shield fog prevention system in accordance with yet another aspect of the invention.
  • FIG. 11 is a schematic representation of a micro-computer controlled embodiment of an automated multiple-PWM, multiple-region eye shield fog prevention system also including a charger;
  • FIG. 12 is a block diagram of a prior system for regulating battery voltage that otherwise depletes over time in use
  • FIG. 13 is a block diagram of an alternate embodiment of a battery compensation system in accordance with an aspect of the invention.
  • FIG. 14 is a flow diagram of software steps for performing the functions of a battery compensation system in accordance with the present invention.
  • FIG. 15 is a sample data table of duty cycles to be applied by a PWM to a battery compensation system in accordance with the invention.
  • FIG. 16 is a block diagram of an alternate embodiment of a battery compensation system adapted for a multi-load device; and [061] FIG. 17 is another sample data table of duty cycles to be applied by a PWM to a battery compensation system in accordance with the invention.
  • Pulse-Width Modulation is used mostly in motor speed control applications for varying the speed of a motor.
  • PWM is characterized by either an analog or a digital signal generated by a pulse width modulator, such as an analog oscillator, or a digital logic device, which provides varying duty cycles that are a percentage on, for example such as 10%, 20%, 30%, and up to 90% or more, on, and a corresponding percentage off, such as 90%, 80%, 30%, and down to 10% or less, off, all as illustrated by numbers 1-9 on FIG. 1.
  • Dotted lines 10 are used to point out the wavelength of the PWM signal, and dotted lines 11 are used to point out the constant voltage magnitude on (high) condition and the constant voltage magnitude off (low) condition.
  • the PWM circuit connected to a 12-volt battery is 40% on and 60% off
  • the PWM signal represents a 12-volt PWM circuit at 40% power.
  • the PWM circuit can run a motor at 40% of its maximum speed, or alternately another percentage of the motor's maximum speed, with a constant voltage source and without adjusting voltage, and this provides the effect of providing a continuous lower voltage by regulating the current delivered to the motor.
  • PWM signals typically have a fixed frequency as is the case with those shown in FIG. 1, and they are typically of a constant full voltage at the full voltage level or a constant no voltage at the low voltage level, though this is not absolutely necessary.
  • an eye shield lens or protective eyewear 200 adapted for at least partially defining an enclosure around a user's eyes and having thereon a single-region resistive transparent conductive film heating member 202.
  • a bus-bar heating element 204 interconnected with a power source (not shown) via a lead wire 212.
  • the film heating member 202 may be comprised of indium-tin oxide (ITO) or other material designed in the form of a resistive element that generates heat when connected to an electrical circuit.
  • a lower buss-bar heating element 206 is provided along a lower edge of the film heating member 202 and which is interconnected with the power source via another lead wire 214.
  • the eye shield lens 200 is irregular shaped having two wider similarly shaped square, rectangular, circular or elliptical areas 209, 210, directly anterior of a user's eye during use, and a narrower area 208 above the bridge of the nose of the user during use.
  • a first embodiment of the invention is provided as a single-PWM, single-region fog prevention system 500 in accordance with the first aspect of the invention.
  • System 500 comprises a single PWM 502 for generating a constant ratio PWM signal 503, switching means 504, such as preferably a MOSFET switch as shown in FIG. 6, a heating element 202 deposited on a lens 200, and a power source 505 having positive and negative terminals 510, 512.
  • the foregoing elements are interconnected in a circuit via a positive lead wire 212 and a negative lead wire 214.
  • PWM signal 503 controls switching means 504 which controls power to the heating element 202.
  • a single-PWM, single-region fog prevention system 600 comprising a battery power source 505 having positive and negative terminals 510, 512, circuit wires 212, 214, PWM 502 (which generates signal 503), eye shield 200 and heating element 202 which is the same as system 500 except the generic switching means has been replaced with a MOSFET switch 602. While preferably a MOSFET switch is employed with the current invention, other switching means including relays, power transistors or other currently known switches may be used without departing from the true scope and spirit of the invention.
  • a single-PWM, single-region fog prevention system 700 comprising a battery power source 505 having positive and negative terminals 510, 512, circuit wires 212, 214, PWM 502 (which generates signal 503), MOSFET 602, eye shield 200 and heating element 202 which system is the same as system 600 except the system 700 further comprises a current adjustment means (CAM) 702.
  • CAM current adjustment means
  • the CAM 702 is shown as a device which comprises a potentiometer and has an internal reference voltage (vref) that is lower than the battery minimum usable voltage and provides an output voltage (input voltage to the PWM), the output voltage from the CAM being some voltage between zero and the reference voltage (vref) based upon the setting of the potentiometer. Responsive to the CAM 702, the PWM 502 produces a corresponding percentage on/off signal that can be varied as a result of output from the CAM.
  • a software control CAM responsive to a MORE (increase) button and responsive to a LESS (decrease) button directly varies the duty cycle of the PWM and thereby varies the amount of current delivered to the heating element 202 without requiring an
  • An output line 704 carrying the output voltage of the CAM 702 is operatively connected between the CAM and the PWM 502.
  • the PWM 502 translates the output voltage from the CAM 702 into a signal having a duty cycle corresponding and proportional to the magnitude of the voltage into the PWM.
  • the duty cycle of the PWM's 502 output will therefore vary in relation to the voltage in from the CAM 702 such that a near-zero input voltage from the CAM to the PWM will result in a near-zero percent on / near 100 percent off duty cycle output of the PWM.
  • the CAM 702 enables varied output duty cycles of the PWM 502.
  • a current adjustment means such as CAM 702 may also be used with a multiple-region embodiment of the invention as shown in FIG. 9.
  • a single-PWM, single-region fog prevention system 800 comprising a power source 505 having positive and negative terminals 510, 512, circuit wires 212, 214, PWM 502 (which generates signal 503), MOSFET 602, eye shield or lens 200 and heating element 202 which system is the same as system 700 except that system 800 further comprises means 802, preferably a microcomputer, for calculating dew point (dew point calculator, or DPC), a temperature sensor 804 and a relative humidity sensor 806 operatively connected to the DPC via signal means 807, 809 and in accordance with another aspect of the invention.
  • This aspect of the invention enables automation of adjustment of the CAM based upon temperature sensor 804 and relative humidity sensor 806 inputs taken from sensing environmental conditions within the space defined between the eye shield 200, near the heating element 202, and the user's eyes.
  • the DPC 802 is operatively connected with the CAM 702 via electrical signal means 803 to signal an increase in current and signal means 805 to signal a decrease in current such that the DPC signals the CAM when environmental conditions within the space defined by the eye shield 200 have changed thus requiring an adjustment to the heating element 202 from the system 800.
  • the DPC 802 calculates the dew point temperature and compares it to the actual temperature within the space defined by the eye shield 200 and signals the CAM 702 accordingly.
  • the dew point temperature as calculated by the DPC 802 is greater than the temperature within a space defined between the eye shield 200 and a user's eyes, then logic within the DPC signals to the CAM 700 to increase the voltage out to the PWM 502, which in turn increases the duty cycle of the PWM output, which in turn increases power to the heating element to increase the temperature of the eye shield 200 and the space between the eye shield and a user's eyes.
  • subsequent sensory input to the system 800 from the temperature sensor 804, the relative humidity sensor 806, and calculations by the DPC 802 would all reflect not only changing ambient conditions, but temperature changes resulting from the aforementioned increase request from the system 800 as well.
  • Further adjustments to the system 800 via the DPC 802 are made at regular intervals in the following manner: as temperature within the space defined by the eye shield 200 falls below the dew point temperature threshold, the system 800 increases power to the heating element 202 via circuit wires 212, 214, and as temperature within the space defined by the eye shield climbs above the dew point temperature threshold, the system decreases power to the heating element via the circuit wires.
  • the aforementioned operation may employ hysteresis, such as used on a typical thermostat, between the increase and decrease states of the system 800 to avoid unwanted rapid switching.
  • an eye shield lens or protective eyewear 300 adapted for at least partially defining an enclosure around a user's eyes and having thereon a plurality of regions or zones of resistive film heating elements or members 302, 304, 306.
  • the film heating element 302 located over a user's right eye during use, is connected to the power source (not shown) by a bus- bar 308 positioned along an upper edge of the film and electrically connected between the film and a lead wire 310 leading to a terminal of the power source.
  • the film heating element 304 located centrally of the eye shield lens 300 just above a user's nose during use, is connected to the power source by a bus-bar 312 positioned along an upper edge of the film and electrically connected between the film and a lead wire 314 leading to a terminal of the power source.
  • a buss-bar 320 positioned along the lower edge of each of the film elements 302, 304, 306 interconnects the film elements to the ground terminal of the power source.
  • the surface area of the film members 302, 306 is larger than the surface area of the film member 304, such that the resistance of the film member 304 is less than that of the other film members. Accordingly, in order to have even heating across the entire lens 300, less current should be applied to the film member 304 than the other film members. Or, alternatively, the divisions between the film members would allow independent heating of one or more of the film members, more or less, than the other film members.
  • an eye shield lens 400 is provided in accordance with the second embodiment of the invention.
  • the eye shield 400 is adapted for at least partially defining an enclosure in front of the user's eyes and has deposited thereon a plurality (24 are shown in FIG. 4) of resistive heating film zones or regions 402 A-X.
  • resistive heating film may be divided into larger or smaller regions than shown without departing from the true scope and spirit of the invention.
  • Each resistive film region 402 A-X is connected to a terminal of a power source via lead wires and discrete buss-bars 404 a-x.
  • a single buss-bar 406, located along a lower edge of each resistive film region 402 A-X interconnects each of the lower ends of film regions to a ground terminal of the power source.
  • the resistive film regions of the fog prevention system of the present invention are preferably deposited on the inner surface of an eye shield 200, 300, 400 with a process known as ion sputtering on a polycarbonate lens, but spray coating and other methods and materials known in the art may be used without departing from the true scope and spirit of the invention.
  • the buss-bars are deposited on the lens 200, 300, 400 by stamping, adhesive backing, or in the case of a conductive silver epoxy buss-bar, it may be applied to a polycarbonate substrate. In the case of a dive mask, while attachment of the resistive film and buss-bars to the inner glass surface of the mask may be employed, a preferred alternative would be to apply these to an inner polycarbonate substrate within the mask.
  • each buss-bar and its corresponding resistive film region are overlapped on edge portions of each so that they conduct electricity to and from the power source as is known in the art.
  • PWMs Pulse-Width Modulators
  • FIGS. 9 and 10 correspondingly larger number of Pulse-Width Modulators (PWMs), or PWM channels, in a multiple- region, multiple-PWM eye shield fog prevention system as shown in FIGS. 9 and 10.
  • PWMs Pulse-Width Modulators
  • FIGS. 9 and 10 fewer or more channels may be provided to accommodate a like number of resistive heating element regions by using an appropriate number PWM channels to accommodate such a plurality of heating element regions.
  • a current adjustment means may be employed with a multiple-region embodiment of the invention, and as shown in FIG. 10, a dew point calculation means (DPC) may also be incorporated into a multiple-region embodiment of the invention to enable automated adjustment of each region as described above.
  • the single output voltage of the CAM is received by a region profile control means ( PC) as further described below and used to adjust the input voltage to each of the multiple PWMs in that embodiment to allow varying of the current out of the PWM based upon user adjustment of a selector or to enable automation as further described below.
  • the DPC of the multiple-region embodiment of the invention functions the same way as described above for the DPC in a single-region embodiment of the invention. Balancing Profiles and Custom Profiles
  • a multiple-PWM, multiple-region fog prevention system 900 comprising a power source 505' having positive and negative terminals 510', 512', circuit wires 212', 214', a multiple-channel PWM 502' which is shown generating signals 503a, 503b and 503c on channels a, b and c, respectively, a CAM 702', a plurality of MOSFETs 602', one MOSFET for each channel of the multiple-channel PWM, an eye shield or lens 300 and heating element regions 302, 304, 306, which system is similar to the single-PWM systems described above, except that system 900 further comprises a region profile controller 902 primarily for balancing power delivered to different-sized and shaped resistive heating film regions (302, 304, 306, or alternatively, 402 A-X), on the eye shield 300 or 400, respectively.
  • a region profile controller 902 primarily for balancing power delivered to different-sized and shaped resistive heating film regions (302, 304, 306, or
  • Differently shaped eye shield lenses 300, 400 would require corresponding region profiles that reflect the shape of the lens and its individual regions such that the electrical characteristics of each region are appropriately weighted so that each region is assured the proper amount of power to keep it in balance with other regions.
  • a region profile is tied to the shape of a region (and the resulting electrical resistivity of that region) and the overall shape of the goggle. If one were to change the shape of a lens, then a different profile would be required for that lens.
  • Each of the regions 302, 304 and 306 have a calculated total electrical resistance (Rt) determined by a formula which considers the type of resistive coating used, and the area of the region where: Rt is the total resistance of the region in ohms, Ri is the resistance per square inch of the resistive thin film in ohms, H is the height of the region in inches and W is the width of the region in inches. Rt may be calculated using the following formula:
  • Each region 302, 304, 306 has a calculated Power Density (Pd) determined by a formula which considers the effective voltage (E) applied to the region, the resistance per square inch (Ri) of the resistive thin film in ohms, and the width (W) of the region in inches.
  • Pd may be calculated using the following formula:
  • region 304 will need .666 times (or 66.6%) of the voltage applied to regions 302 and 304. This result is confirmed by recalculating the power density (Pd) for region 304 as 6.66 2 / (10 x 2 2 ) which equals 1.11 watts per square inch.
  • results in the foregoing example disclose a balancing profile. More precisely, these results yield the analog or digital proportional input voltages needed to power differing size regions on a specific goggle to the same power densities.
  • a multiple-PWM, multiple-region fog prevention system 1000 similar to system 900 is shown comprising a power source 505' having positive and negative terminals 510', 512', circuit wires 212', 214', a multiple-channel PWM 502' which is shown generating signals 503a, 503b and 503c on channels a, b and c, respectively, a CAM 702', a plurality of MOSFETs 602', one MOSFET for each channel of the multiple-channel PWM, an eye shield or lens 300 and heating element regions 302, 304, 306.
  • System 1000 differs from system 900 in that in system 1000 the RCP 902 further comprises a user-selectable region profile control switch 1002 which enables a user to select a balanced profile or one of several custom profiles for customized power delivery as further described below to the different-sized and shaped resistive heating film regions (302, 304, 306, or alternatively 402 A-X) on the eye shield 300 or 400, respectively.
  • the RCP 902 further comprises a user-selectable region profile control switch 1002 which enables a user to select a balanced profile or one of several custom profiles for customized power delivery as further described below to the different-sized and shaped resistive heating film regions (302, 304, 306, or alternatively 402 A-X) on the eye shield 300 or 400, respectively.
  • a custom profile may be used to enable predetermined proportional input voltages to a particular resistive film region, or regions, necessary to achieve a desired power density pattern allowing one or more regions 302, 304, 306, or alternatively 402 A-X, to intentionally become hotter or cooler than other regions for specific intended purposes.
  • the CAM 702' provides overall automatic variability between all the way cool to all the way hot for each of the regions 302, 304, 306, or alternatively regions 402 A-X, and it is the job of the PC 902' cognizant of the profile to know how much power to apply proportionally to each of the regions in accordance with the overall adjustment.
  • the CAM 702' may be set to a 50% overall power application or duty cycle, the RPC will put out a 50% adjustment for the largest region 302, 304, 306 (or alternatively 402 A-X) and a proportionally smaller output for smaller regions in accordance with a particular predetermined profile.
  • Examples of custom profiles may involve a profile for a snow boarder that may require added heat to one side of a goggle lens to prevent fogging or to reduce icing of that side depending upon which foot the rider usually leads downhill, or as another example, a particular lens or goggle shape and configuration may require added heating at the edges of the goggle to prevent fogging or icing.
  • a particular lens or goggle shape and configuration may require added heating at the edges of the goggle to prevent fogging or icing.
  • custom settings for particular weather conditions such as a rainy day, a snowy day, a sunny day, or different depths and water temperatures for a dive mask, etc.
  • Custom profiling may be user-selectable with the custom profile switch 1002.
  • the multiple-PWM, multiple-region fog prevention system 1000 shown in FIG. 10 also further comprises means for calculating dew point 802' (also known as the dew point calculator, or DPC), a temperature sensor 804' and a relative humidity sensor 806' operatively connected to the DPC via signal means 807', 809' for automated control of the system 1000.
  • the DPC 802' and sensors 804', 806' are for the same purposes and function in the same way as the DPC 802 and sensors 804, 806 shown and described above in connection with the first embodiment of the invention, except the signals from the DPC 802' are used by the CAM and RPC to provide master controls for a plurality of signal lines a, b, c to the PWM 502'.
  • PWMs of either embodiment of the invention, and associated functions such as dew point calculation, profile table lookup, variable current adjustment mechanism, switching means, and the like, may be preferably accomplished with a microcomputer, any of these functions may be performed with other technology, such as a programmable logic array (PLA), a state machine, analog circuitry or other digital logic, without departing from the true scope and spirit of the invention.
  • PPA programmable logic array
  • System 1100 comprises a power source, such as rechargeable batteries 1102, an on/off switch 1104, a heat control switch 1106, a profile selector 1108 and a charger jack 1110.
  • Charger jack 1110 may comprise a mini-USB charger jack or other suitable charging system as known in the art.
  • System 1100 further comprises a power level indicator display 1112 preferably comprising a plurality of LEDs configured as a bar graph to indicate a selected power level and a battery life indicator display 1114 preferably comprising a plurality of LEDs configured as a bar graph to indicate remaining battery life.
  • System 1100 further comprises an eye shield 1116 having deposited thereon a plurality of thin film heating elements 1118, 1120, 1122.
  • the eye shield 1116 is adapted for defining at least a partial enclosure in front of a user's eyes.
  • a temperature sensor 1124 and a relative humidity sensor 1126 are positioned within the partial enclosure defined by the eye shield 1116 for aiding with calculation of dew point temperature.
  • the system 1100 further preferably comprises a low-power microcontroller 1128 preferably further comprising PWM logic, other programmable logic and some combination of RAM/ROM/FLASH Memory 1130 as is known in the art of microelectronics.
  • the microcomputer controller 1128 is operatively connected to a battery charger circuit 1132.
  • the battery charger circuit 1132 is connected to the battery charger jack 1110 and rechargeable batteries 1102.
  • the battery charger circuit 1132 is primarily responsible for maintaining the rechargeable batteries 1102, including routing a charge from the charger jack 1110 to the rechargeable batteries when required and turning off, disconnecting the charger from the batteries when they have been fully charged and reporting battery level to the microcontroller 1128.
  • the system 1100 further comprises battery life indicator display logic 1134 such that when the microcontroller 1128 receives battery level information from the battery charger circuit as previously described, the microcontroller may signal the battery life indicator display logic upon user request or otherwise.
  • the battery life indicator display logic 1134 converts the signal received from the microcontroller 1128 into the logic necessary to drive the battery life indicator display 1114.
  • the battery life indicator display logic 1134 may include a latch to hold the latest value on the display, relieving the microcomputer to attend to other tasks.
  • the system 1100 further comprises an eye shield heater driver 1136 comprising a plurality of driver channels 1138, 1140, 1142, each channel corresponding to a thin film heating element region or zone, such as regions 1118, 1120, 1122, respectively.
  • the primary responsibility of the microcontroller 1128 is to keep the heater driver 1136 and related channels 1138, 1140, 1142 operating at an optimal and preferably balanced level to eliminate and prevent fogging while conserving battery life.
  • the microcontroller 1128 may operate in manual heat control or automatic heat control modes.
  • the microcontroller 1128 adjusts power to the eye-shield heater driver 1136 according to a predetermined profile contained in microcontroller memory 1130 and which controls the duty cycle signal on each individual PWM channel in a manner consistent with the size, shape and electrical resistivity of each associated heating element 1118, 1120, 1122 to provide power density balancing.
  • the system 1100 may engage a custom profile, also stored in microcontroller memory 1130, resulting in application of a custom power density profile to the heater driver 1136 resulting in a desired portion of the eye shield 1116 receiving more power than another portion.
  • the system 1100 further comprises a dew point calculator (DPC) 1144 which calculates dew point temperature from temperature sensor 1124 and relative humidity sensor 1126. During automatic mode balancing of heating levels of the system 1100, the system adjusts the heat to the regions in accordance with a calculated dew point from the DPC 1144.
  • the DPC 1144 calculates the dew point temperature and compares it to the actual temperature within the space defined by the eye shield 1116 and signals the microcontroller 1128 accordingly.
  • the dew point temperature as calculated by the DPC 1144, is greater than the temperature within the space defined between the eye shield 1116 and a user's eyes, then logic within the microcontroller signals to the eye shield heater driver 1136 to increase the duty cycle of the PWM channels in accordance with the profile in effect to increase the temperature of the eye shield 1116 and the space between the eye shield and a user's eyes.
  • logic within the microcontroller signals to the eye shield heater driver 1136 to increase the duty cycle of the PWM channels in accordance with the profile in effect to increase the temperature of the eye shield 1116 and the space between the eye shield and a user's eyes.
  • Further adjustments to the system 1100 via the DPC 1144 are made by the microcontroller 1128 at regular intervals in the following manner: as temperature within the space defined by the eye shield 1116 falls below the dew point temperature threshold, the system 1100 increases power to the heating elements 1118, 1120, 1122 via PWM channels 1138, 1140, 1142, and as temperature within the space defined by the eye shield climbs above the dew point temperature threshold, the system decreases power to the heating elements via the PWM channels.
  • the aforementioned operation may employ hysteresis, such as used on a typical thermostat, between the increase and decrease states of the system 1100 to avoid unwanted rapid switching.
  • microcontroller 1128 determines from memory 1130 the current operating power level being supplied to the heater driver 1136 and sends a power level signal to the power level display logic 1146, which in turn converts the signal received from the microcontroller 1128 into the logic necessary to drive the power level indicator display 1112.
  • the power level indicator display logic 1146 may include a latch to hold the latest value on the display, relieving the microcomputer to attend to other tasks.
  • FIG. 12 a block diagram of a battery regulation system is illustrated for maintaining a constant regulated voltage to a hand-held electronic device, such as a cell phone (represented by load 1235), including a lithium-ion battery 1205, a positive circuit wire 1210 carrying 3.7 to 3.2 Volts DC, which is depleting with battery discharge over time in use as specified, to a voltage regulator 1225.
  • the voltage regulator 1225 is set to supply a regulated, constant 3.0 Volts DC via line 1230 as specified to the load 1235.
  • a typical voltage regulator supplies voltage at the desired output level only when the actual supply voltage from the battery is somewhat greater than the desired output voltage.
  • the battery voltage would need to be at least 3.2 Volts DC for the voltage regulator to produce the desired 3.0 Volts DC.
  • the circuit back to the negative terminal of the battery 1205 is completed with circuit line 1220, and the system is grounded at 1240.
  • Such a system is known to be important to provide constant voltage necessary to efficient functioning of cell phones.
  • a battery compensation system using PWM differs in that it does not maintain a constant voltage until the battery is discharged, but rather it varies the PWM cycle to maintain constant power to the load despite the voltage drop until the battery is discharged and no longer able to maintain that power level.
  • a battery compensation system 1300 using pulse-width modulation (PWM) 1340 comprising a battery 1305, preferably a lithium-ion battery, having positive parallel circuit lines 1380 leading to a voltage divider circuit 1310, 1315 for proportionally adjusting the voltage to a measurable range, an analog to digital converter 1335 for receiving the output from the voltage divider and converting it into a digital voltage value, a microprocessing unit (MPU) 1330 and a single-channel pulse-width modulator (PWM) 1340.
  • PWM pulse-width modulation
  • the voltage divider circuit 1310, 1315 comprises two resistors 1310, 1315 in series between positive and negative terminals of the battery 1305 for proportionally adjusting the voltage to a measurable range, the voltage divider circuit preferably having a tap between the two resistors (shown as the intersection of lines between the two resistors 1310, 1315) adapted to provide the proportional voltage measurement to an I/O pin on the analog-to-digital converter 1335.
  • the user-determined, or provided, power setting comprises a power level setting set by a dial, a knob, or a push button system 1325, together with some form of visual feedback to the user (e.g., 1612 of FIG. 16) to further enable selection of the setting.
  • the PWM 1340 drives the load 1345, which represents a portable electronic device, or elements of a portable electronic device, such as for example heating elements on an anti-fog ski goggle, a heated diving mask, a heated medical or technical eye shield, or the like.
  • the load 1345 may represent a heater on a portable electronic device such as a hand-held GPS unit, a cell phone, a radio, an electronic tablet, a reader, or other portable computer or the like, to be driven by the PWM circuitry and battery of the device.
  • a power level selector 1325 is provided with more and less controller for allowing user selection of a desired power setting, such as 20%, 40%, 60%, 80% 100%, corresponding to, for example, 2 Watts, 4 Watts, 6 Watts, 8 Watts and 10 Watts respectively 1350, 1355, 1360, 1365, 1370 respectively, for power to drive a heater (e.g., heating element 202 of FIG. 5) on the powered electronic device (e.g., an anti-fog goggle).
  • a heater e.g., heating element 202 of FIG. 5
  • the MPU 1330 is one of several possible means for receiving voltage input and user-determined power setting input for determining a compensating duty cycle 1350, 1355, 1360, 1365, 1370 for application to the PWM 1340 to drive the load consistently at the user-determined power setting despite decrease in voltage from the battery 1305 resulting from battery depletion.
  • the MPU 1330 is capable of executing software code steps 1400 as set forth in the flow chart, to determine a compensating duty cycle 1350, 1355, 1360, 1365, 1370 for application by the software to the PWM 1340 to drive the load 1345 consistently at the user-determined power setting despite decrease in battery voltage resulting from depletion of the battery 1305.
  • the MPU 1330 is battery- powered, and a readily-available microprocessing unit having on-board analog-to-digital conversion means 1335 may be used for the present invention.
  • the software steps as shown at 1405 for operation of the invention comprise, after starting at 1405, reading of the battery voltage 1410, reading the user setting for power level 1415, looking up the battery voltage compensation value for a PWM duty cycle 1420 to be applied to the PWM circuit 1425.
  • the portable electronic device 1345 e.g., 200 of FIG. 5
  • the compensation system of the invention may be operated continuously, or it may be controlled with an on/off switch to toggle between battery conservation mode and battery compensation mode.
  • battery compensation mode in accordance with the invention may be employed when extra battery power is available to compensate for a drop in voltage resulting from battery depletion by increasing the duty cycle 1350, 1355, 1360, 1365, 1370 to be applied to the PWM 1340 to overcome what would otherwise be a drop in power associated with the depleted battery 1305.
  • determination of a compensating duty cycle 1350, 1355, 1360, 1365, 1370 may comprise a data lookup table 1500 of PWM duty cycle values organized according to power setting (shown in Watts across the top of the table 1500) and battery depletion voltage drop (shown in the left-hand column of FIG. 15) and for use by the code steps 1410, 1415, 1420, 1425 run by the microprocessor to select a compensating duty cycle for application to the PWM to drive the load 1345 consistently at the user-determined power setting despite a decrease in voltage from the battery 1305 resulting from battery depletion.
  • This embodiment of the invention preferably comprises a lookup table 1500 stored in microprocessor memory (e.g., 1630 of FIG.
  • the data lookup table 1500 shown in FIG. 15 is organized by user heater level setting (shown in Watts across the top of the table 1500) and actual heater power for a given battery voltage ranging from 8.4 Volts DC (assuming two lithium-ion batteries of 3.7 Volts DC each in series) depleted down to 6.8 Volts DC (shown in the left-hand column of the table 1500).
  • 8.4 Volts DC assuming two lithium-ion batteries of 3.7 Volts DC each in series
  • 6.8 Volts DC shown in the left-hand column of the table 1500.
  • the number of duty cycles increases as shown as a greater number of Watts is specified by the user, and a larger number of duty cycles is required to compensate for increasingly depleted charge in the battery.
  • 86.5 duty cycles that is PWW will switch the power on 86.5 cycles for every 100 cycles - or in other words the PWM controls transmission of power to allow power to the load 86.5 cycles out of a hundred, or 86.5 on and 13.5 off.
  • the number of duty cycles required increases as the battery depletes further and the higher the power level selected by the user.
  • example data table 1500 is based upon a system using two lithium-ion batteries of 3.7 Volts DC each in series, the invention is not limited to a two-battery, or otherwise plural-battery, system, and the battery compensation system of the invention may be used with a single battery with an appropriately adjusted data table, or calculations as the case may be. Further, while the number of duty cycles is represented as an integer with a decimal portion, these numbers may be rounded to the nearest integer in an actual PWM implementation.
  • the software steps 1410, 1415, 1420, 1425 themselves may be used to calculate a compensating duty cycle 1350, 1355, 1360, 1365, 1370 for application to the PWM 1340 to drive the load 1345 consistently at the user-determined power setting despite decrease in voltage from the battery 1305 resulting from battery depletion.
  • the formula for determining the compensating duty cycle 1350, 1355, 1360, 1365, 1370 for this embodiment of the invention which is the same formula used to determine data table 1500 duty cycle values (from user input power settings - represented by the Watts settings across the top of table 1500 - and measured voltage) used in the table is as follows:
  • the compensation system 1300 in accordance with the invention enables maintenance of a user-selected and/or desired power setting to drive the load 1345 to consistently heat a portable device (e.g., goggle lens 200 of FIG. 5), such as anti-fog goggles or a hand-held GPS, radio or phone, despite partial depletion of a device battery 1305, as long as there is sufficient battery charge to maintain the system-compensated power output.
  • a portable device e.g., goggle lens 200 of FIG. 5
  • the system 1300 compensates by increasing the duty cycle 1350, 1355, 1360, 1365, 1370 of the PWM 1340 driver for the device 1345.
  • a compensation system 1600 adapted for use preferably in heating a plurality of devices, for example a plurality of loads 1618, 1620, 1622 of a portable electronic device 1616.
  • the plurality of loads 1618, 1620, 1622 represent a portable electronic device, elements of a portable electronic device, or a plurality of such devices, such as heating elements on an anti-fog ski goggle, a heated diving mask, a heated medical or technical eye shield, or the like.
  • the load 1345 may represent a heater or other appropriately PWM driven element on a portable electronic device such as a hand-held GPS unit, a cell phone, a radio, an electronic tablet, a reader, or other portable computer or the like, to be powered by the PWM circuitry and battery of the device.
  • the example compensation system 1600 comprises a power source, such as rechargeable batteries 1602, an on/off switch 1604, a power level control 1606 and a charger jack 1610.
  • Charger jack 1610 may comprise a mini-USB charger jack or other suitable charging system as known in the art.
  • System 1600 further comprises a power level indicator display 1612 preferably comprising a plurality of LEDs configured as a bar graph to indicate a selected power level and a battery life indicator display 1614 preferably comprising a plurality of LEDs configured as a bar graph to indicate remaining battery life.
  • System 1600 further comprises a portable electronic device 1616 having illustrated therewith a plurality of loads 1618, 1620, 1622.
  • the system 1600 further preferably comprises a low-power microcontroller 1628 preferably further comprising PWM logic, other programmable logic and some combination of RAM/ROM/FLASH Memory 1630 as is known in the art of microelectronics.
  • the microcomputer controller 1628 is operatively connected to a battery charger circuit 1632.
  • the battery charger circuit 1632 is connected to the battery charger jack 1610 and rechargeable batteries 1602.
  • the battery charger circuit 1632 is primarily responsible for maintaining the rechargeable batteries 1602, including routing a charge from the charger jack 1610 to the rechargeable batteries when required and disconnecting the charger from the batteries when they have been fully charged and reporting battery level to the microcontroller 1628.
  • the system 1600 further comprises battery life indicator display logic 1634 such that when the microcontroller 1628 receives battery level information from the battery charger circuit as previously described, the microcontroller may signal the battery life indicator display logic upon user request or otherwise.
  • the battery life indicator display logic 1634 converts the signal received from the microcontroller 1628 into the logic necessary to drive the battery life indicator display 1614.
  • the battery life indicator display logic 1634 may include a latch to hold the latest value on the display, relieving the microcomputer to attend to other tasks.
  • the system 1600 further comprises drivers 1636 comprising a plurality of driver channels 1638, 1640, 1642, each channel corresponding to a load, such as loads 1618, 1620, 1622, respectively.
  • drivers 1636 comprising a plurality of driver channels 1638, 1640, 1642, each channel corresponding to a load, such as loads 1618, 1620, 1622, respectively.
  • MOSFET for system 1600 is contained in the drivers 1636.
  • the primary responsibility of the microcontroller 1628 is to keep the driver 1636 and related channels 1638, 1640, 1642 operating at an optimal and preferably balanced level while conserving battery life.
  • the microcontroller 1628 adjusts power to the device driver 1636 according to a predetermined profile contained in microcontroller memory 1630 and which controls the duty cycle signal on each individual PWM channel in a manner consistent with the size, shape and electrical resistivity of each associated load 1618, 1620, 1622 to provide power density balancing.
  • the system 1600 may engage a custom profile, which may be stored in microcontroller memory 1630, resulting in application of a custom power level profile to the driver 1636 resulting in a desired portion of the portable electronic device 1616 receiving more or less power than another portion.
  • microcontroller 1628 comprises a voltage divider circuit 1610 for proportionally adjusting the voltage to a measurable range, and an analog to digital converter (ADC) 1605 preferably contained in the microcontroller 1628 for receiving the output from the voltage divider and converting it into a digital voltage value.
  • the voltage divider circuit 1610 comprises two precision resistors in series (as described above in connection with FIG. 13) between positive and negative terminals of a battery or batteries 1602 for proportionally adjusting the voltage to a measurable range, the voltage divider circuit preferably having a tap between the two resistors adapted to provide the proportional voltage measurement to an I/O pin on microcontroller 1628 containing the analog-to-digital converter 1605.
  • the user-determined, or provided, power setting comprises a power level setting set by a dial, a knob, or a push button system (e.g., 1606), together with some form of visual feedback to the user (e.g., 1612) to further enable selection of the setting.
  • the user may be apprised of the power level being supplied to the load elements of the system.
  • a user may select a desired power level in accordance with visual feedback from the power level display 1612.
  • the microcontroller 1628 determines from memory 1630 the current operating power level being supplied to the driver 1636 and sends a power level signal to the power level display logic 1646, which in turn converts the signal received from the microcontroller 1628 into the logic necessary to drive the power level indicator display 1612.
  • the power level indicator display logic 1646 may include a latch to hold the latest value on the display, relieving the microcomputer to attend to other tasks.
  • FIG. 17 there is shown an alternate data lookup table 1700 stored in microprocessor memory 1630 for allowing software determination of an applied duty cycle corresponding to a custom power level profile, for example for each load of a plurality of different loads, in a portable electronic device, for example when less than full power to the device may be desirable.
  • the data lookup table 1700 shown in FIG. 17 is organized by user heater level setting (shown in Watts across the top of the table 1700) and actual heater power for a given battery voltage ranging from 8.4 Volts DC (assuming two lithium-ion batteries of 3.7 Volts DC each connected in series) depleted down to 6.8 Volts DC (shown in the left-hand column of the table 1700).
  • the number of duty cycles required increases as the battery depletes further and the higher the power level selected by the user.
  • the example data table 1700 is based upon a system using two lithium-ion batteries of 3.7 Volts DC each in series, the invention is not limited to a two-battery, or otherwise plural-battery, system, and the battery compensation system of the invention may be used with a single battery with an appropriately adjusted data table, or calculations as the case may be.
  • the number of duty cycles is represented as an integer with a decimal portion, these numbers may be rounded to the nearest integer in an actual PWM implementation.
  • the table 1700 may be part of a more comprehensive data table and still fall within the true scope and spirit of the invention, however it is contemplated that the system 1600 will ascertain the battery voltage and the user-determined power level input, and determine the appropriate duty cycle according to those inputs and in harmony with either an even power level profile, or alternatively a custom power level profile, such as would the be case for example in an evenly-heated eye shield device or a custom-heated eye shield device described previously for example in connection with FIG. 11.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Computer Hardware Design (AREA)
  • Health & Medical Sciences (AREA)
  • Ophthalmology & Optometry (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)
PCT/US2014/059040 2013-10-06 2014-10-03 Battery compensation system using pwm WO2015051248A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
KR1020167011997A KR20160066042A (ko) 2013-10-06 2014-10-03 Pwm을 사용하는 배터리 보상 시스템
EP14850350.1A EP3053260A4 (en) 2013-10-06 2014-10-03 Battery compensation system using pwm
CA2925348A CA2925348A1 (en) 2013-10-06 2014-10-03 Battery compensation system using pwm
JP2016520014A JP6563387B2 (ja) 2013-10-06 2014-10-03 パルス幅変調器（ｐｗｍ）を使用した電池補償システム
AU2014329396A AU2014329396B2 (en) 2013-10-06 2014-10-03 Battery compensation system using PWM
CN201480055014.1A CN105684284A (zh) 2013-10-06 2014-10-03 利用pwm的电池补偿系统

Applications Claiming Priority (2)

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US14/046,969 US9419520B2 (en) 2012-02-16 2013-10-06 Battery compensation system using PWM
US14/046,969 2013-10-06

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JP (1) JP6563387B2 (ja)
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AU2014329396B2 (en) 2019-05-16
JP2016536957A (ja) 2016-11-24
CA2925348A1 (en) 2015-04-09
AU2014329396A1 (en) 2016-05-05
CN105684284A (zh) 2016-06-15
JP6563387B2 (ja) 2019-08-21
EP3053260A4 (en) 2017-05-10
EP3053260A1 (en) 2016-08-10
KR20160066042A (ko) 2016-06-09

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