JP2022542085A - Portable Test Meter to Monitor Backlight Battery Depletion - Google Patents

Abstract

A test meter including a housing, a controller, a backlit display, and a battery monitoring circuit, and an associated method for monitoring the status of the backlight battery of the meter. The off time of the meter is measured and compared to the predetermined recovery time of the backlight battery. If the off-time of the meter is greater than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after the backlight is energized, and make the measured voltage exceed the threshold voltage of the backlight battery. Compare with a first predetermined voltage. If the measured voltage is less than the first predetermined voltage, comparing the measured voltage to a second predetermined voltage between the first predetermined voltage and the threshold voltage. If the measured voltage is less than the second predetermined voltage, display a low battery warning. [Selection drawing] Fig. 1A

Description

TECHNICAL FIELD This application relates generally to the field of test meters, and more specifically to portable test meters used for periodic monitoring of a subject and battery depletion used in such portable test meters. and related methods for monitoring

Handheld devices, such as portable test meters, typically require a display for communicating the results of test measurements to the user of the test meter. Such displays may include a backlight to facilitate reading in low light. What is desired is a compact, lightweight, long-lasting portable test meter that does not require frequent battery replacement.

Some technologies, such as thin film transistor (TFT) display technology, provide enhanced color graphics that are desirable to users. However, these displays may not be fully readable without a backlight and are not suitable for use in portable test instruments that operate for weeks or months without battery replacement. The reason is that the backlight cannot be disabled to save power. Therefore, such displays that require constant backlighting are typically not available or considered for use in such portable test instruments.

Additionally, a commonly used display in test instruments is a passive liquid crystal display (LDC), which can still be read without an active backlight. Therefore, existing architectures for portable test instruments do not take into account the practical problems encountered with portable test instruments having TFT display screens. This requires increased monitoring and management of backlight subsystems to prevent unpredictable power loss to test instruments.

Additionally, commonly used battery depletion detection algorithms only allow the battery voltage to be seen prior to start-up. In such cases, the effects of cell internal resistance, ionic mobility, and temperature are not considered. However, such a simple test works, but only for cells subject to relatively small and steady current drains.

So that the features of the present invention can be understood, the detailed description can be had by reference to specific embodiments, some of which are illustrated in the accompanying drawings. The drawings, however, illustrate only particular embodiments and should therefore not be considered limiting of the scope of the disclosed subject matter, as it may encompass other embodiments. Please note. The drawings are not necessarily to scale, emphasis generally being placed on illustrating features of particular embodiments. In the drawings, like numerals are used throughout the various drawings to denote like parts.

1 illustrates a rear view of a partially disassembled handheld test meter according to aspects described herein. FIG. 1 illustrates a front view of a handheld test meter, according to aspects described herein. FIG. 1B is a block diagram of a controller used and powered by the portable test meter of FIG. 1A; FIG. 2B is a plan view of a circuit board containing electrical components of the handheld test meter of FIGS. 1A and 2A; FIG. 1B shows a schematic diagram of a backlight battery and a main battery connected within the portable test meter of FIG. 1A. FIG. 1 illustrates a backlight driver circuit with a battery monitoring circuit according to aspects described herein for use in a test meter; FIG. 4 shows voltage recovery characteristics of a battery intended for use as a test meter backlight battery, according to embodiments described herein. FIG. 4 shows voltage recovery characteristics of a battery intended for use as a test meter backlight battery, according to embodiments described herein. 5B illustrates a method for monitoring the status of a backlight battery, such as a backlight battery having the characteristics shown in FIGS. 5A-5B, for use in a portable test meter, according to aspects described herein. FIG.

The following detailed description should be read with reference to the drawings, in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description clearly enables a person skilled in the art to make and use the invention, and describes several embodiments, applications, variations, alternatives and uses of the invention, among which is the present invention. It also includes the best mode presently contemplated of carrying out the invention.

As used herein, the term “about” or “approximately” any numerical value or range thereof means that any portion or collection of elements functions for the intended purpose stated herein. Show appropriate dimensional tolerances to allow Further, as used herein, the terms “patient,” “host,” “user,” and “subject” refer to any human or animal subject, and the system or method used in humans. While not intended to be limiting, use of the subject technology on human patients represents a preferred embodiment.

The present disclosure relates, in part, to portable test meters such as those used to periodically measure a subject's blood glucose level. Some of these test meters have a main power supply that electrically powers a controller and display included in the test meter along with any measurement subsystems such as electrochemical test circuits for monitoring blood glucose. Equipped with a battery or primary battery. For portable test instruments with TFT or similar type displays, there is an additional need to power the backlight of the display. Accordingly, the test meter can further include a dedicated backlight battery and enhanced battery monitoring to expedite replacement of the backlight battery before it runs out. More specifically, the main battery may be used to power the test instrument's controller, display logic, and any measurement subsystems, while the dedicated backlight battery is used only to power the backlight. may be used. Such a configuration allows the use of TFT displays in portable test instruments despite the problem that TFT displays require a backlight for viewing. In one embodiment, a conventional coin cell battery is used as a dedicated backlight battery to reduce the footprint of the portable test meter. This is because coin cells, which cannot normally be used in backlights, operate in an unconventional manner as described herein.

Additionally, coin cell batteries, such as CR2032 lithium batteries, have been commonly used in portable test instruments, but are not rated for use in high power consumption components such as backlights. However, the technology described herein allows these common batteries to be used. This is because these technologies take advantage of the specific usage patterns of portable test meters, such as those routinely used to measure blood glucose in diabetics.

Generally speaking, according to one embodiment, a portable test meter is provided. The portable test meter includes means for monitoring the backlight battery, such as a battery monitoring circuit. A test meter, for example, includes a housing that holds a controller for periodically measuring a subject's blood glucose level. The test meter also includes a display, such as a TFT display with a backlight, and circuitry for monitoring a dedicated backlight battery. This monitoring circuit is used to measure the off-time of the meter and compare it to the predetermined recovery time of the backlight battery. If the off-time of the meter is greater than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after the backlight is energized, and make the measured voltage exceed the threshold voltage of the backlight battery. Compare with a first predetermined voltage. If the measured voltage is less than the first predetermined voltage, comparing the measured voltage to a second predetermined voltage between the first predetermined voltage and the threshold voltage. If the measured voltage is less than the second predetermined voltage, display a low battery warning.

In another embodiment, this specification discloses a method for monitoring the backlight battery status of a portable test meter. A test meter includes a meter housing that holds a number of components, including a controller, and a display is provided in the meter housing. The display includes a TFT screen and a backlight. The backlight is powered by a backlight battery. According to the method, the off-time of the meter is measured and compared to a predetermined recovery time of the backlight battery. If the off-time of the meter is greater than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after the backlight is energized, and make the measured voltage exceed the threshold voltage of the backlight battery. Compare with a first predetermined voltage. If the measured voltage is less than the first predetermined voltage, comparing the measured voltage to a second predetermined voltage between the first predetermined voltage and the threshold voltage. If the measured voltage is less than the second predetermined voltage, display a low battery warning.

The above embodiments are intended to be examples only. It will be readily apparent from the discussion that follows that other preferred embodiments are within the intended scope of the disclosed subject matter.

Next, a specific working example will be described. First, portable test meters and battery monitoring techniques are described in connection with FIGS. 1-6.

FIG. 1A shows a rear view of a portable test meter 10 defined by meter housing 11, which is configured and sized to hold a plurality of components. It is defined by a meter housing 11 having an interior. These components include controller 38 (see FIG. 2A), main battery 50 and backlight battery 52 . As shown in FIG. 1B, the display 14 according to this embodiment includes a thin film transistor (TFT) screen and backlight and is positioned on the front side of a similar portable test and measurement instrument 10'. In one example of operation, the main battery 50 powers the TFT display logic as well as the controller 38 . On the other hand, the backlight battery 52 only powers the display backlight.

Depending on the configuration, the backlight may be light emitting diodes (LEDs) or an array of LEDs, and the array may contain from 1 to 50 LEDs. In other embodiments, the backlight may be a fluorescent device, an electroluminescent device, an organic light emitting diode (OLED), or disposed within the housing 11 of the test meter 10, 10' of FIGS. 1A and 1B. It can be any other light source available.

FIG. 1B shows a diabetes management system that includes a portable test meter 10 ′ and a biosensor in the form of a glucose test strip 62 . Handheld test instruments 10, 10' have different physical appearances, but generally operate in the same manner. Note that the measuring device (measuring device unit) may also be called an analyte measurement management unit, a glucose measuring device, a measuring device, or an analyte measuring device (not shown). In one embodiment, the meter unit may be combined with an insulin delivery device, an additional analyte test device, and a drug delivery device. The meter unit may be connected to a remote computer or server via cable or via a suitable wireless technology such as GSM, CDMA, Bluetooth, WiFi, or the like. Such a management system is described in greater detail in U.S. Pat. No. 8,709,232, entitled "Analyte measurement technique and system," issued Apr. 29, 2014, the entirety of which is incorporated herein by reference. incorporated herein.

Returning to FIG. 1B, glucose meter or meter unit 10 ′ is defined by housing 11 having a plurality of user interface buttons ( 16 , 18 , 20 ) located on facing surfaces of housing 11 . Display 14 is provided in addition to test strip port opening 22 configured to receive a biosensor (test strip 62). User interface buttons (16, 18, 20) may be configured to allow data entry, menu navigation, and command execution. User interface button 18 may be in the form of a two-way toggle switch. The number and orientation of the user interface buttons can have various configurations, and the three interface buttons depicted are an example. The data may include values representative of analyte concentrations and/or information related to an individual's daily life. The information on daily life may include the individual's food intake, medication status, health checkup status, health condition, and exercise level. The electronic components of the portable test meter 10, 10' may be located on a circuit board 34 (Fig. 2B) that is positioned inside the meter housing 11, 11'.

FIG. 2A is a partial block diagram of a portable test meter showing controller 38 connected to power supply 220 . Controller 38 includes central processing unit (CPU) 212 , random access memory (RAM) 214 , analog-to-digital converter (ADC) 216 , and general purpose input/output (GPIO) 218 . ADC 216 is connected to the backlight battery monitoring circuit and can be used to measure its voltage. The GPIO 218 can communicate with the display to turn on the backlight 60 (see FIG. 3) or with the battery monitoring circuit (see FIG. 4).

FIG. 2B shows (simplified) the electronic components located on the top surface of the circuit board 34 located inside the test meter 10 of FIG. 1A. These electronic components include test strip port connector 22 , op amp circuitry 35 , controller 38 , display connector 14 a , non-volatile memory 40 , clock 42 and first radio module 46 . On the underside of circuit board 34 , electronic components may include a battery connector (not shown) and data port 13 . The controller 38 includes the test strip port connector 22, the operational amplifier circuit 35, the first radio module 46, the display 14, the non-volatile memory 40, the clock 42, at least one battery, the data port 13, and the user interface buttons 16,18,20. may be electrically connected to

Opamp circuitry 35 may include two or more opamps configured to provide a portion of the potentiostat and current measurement functions. Potentiostat function may refer to the application of a test voltage between at least two electrodes of a test strip used in conjunction with a test meter. A current function may refer to the measurement of test current resulting from an applied test voltage. Current measurements may be performed using current-to-voltage converters. Controller 38 may, for example, be in the form of a mixed signal microprocessor (MSP), such as the Texas Instruments MSP430. The TI MSP430 may also be configured to perform some of the potentiostat and current measurement functions. Additionally, controller 38 may include volatile and non-volatile memory. In another embodiment, many of the electronic components may be integrated with the controller in the form of an application specific integrated circuit (ASIC).

Test strip port connector 22 may be configured to form an electrical connection to a test strip, such as test strip 62 . Display connector 14 a may be configured to attach to display 14 . Display 14 may be in the form of a liquid crystal display to report measured glucose levels and to facilitate entry of lifestyle related information using interface buttons 16 , 18 , 20 . More specifically, and according to this embodiment, display 14 includes a backlight. Data port 13 can receive a suitable connector attached to connection leads (not shown), thereby allowing test instrument 10 to be linked to an external device such as a personal computer. Data port 13 may be any port that allows transmission of data, such as, for example, a serial, USB, or parallel port. Clock 42 holds the current time relative to the geographic region in which the user is located and may be configured to measure time, as described in more detail below. The test meter may be configured to be electrically connected to a power source, such as, for example, at least one included battery, as shown according to FIG.

FIG. 3 schematically shows further details of the power supply configuration for test meter 10 of FIG. In this configuration, controller 38 is connected to a main battery 50 for powering controller 38 . Backlight battery 52 is utilized to power backlight 60 of display 14 via backlight driver circuit 54 .

FIG. 4 shows a backlight driver circuit 410 according to an embodiment, as used with a battery monitoring circuit 420. As shown in FIG. The exemplary backlight driver circuit 410 employs a switch mode boost regulator operating in a constant current configuration. The drive circuit 410 outputs to the LED backlight via LED_A and LED_K. LED current is controlled by resistor R32. In such a case, a reference voltage, eg, 500 mV, may be maintained at pin FB of U10 to provide approximately 10 mA of LED drive current. Battery monitor circuit 420 measures voltage VBAT2 via an analog-to-digital converter (ADC). For example, to facilitate backlight battery measurements, the controller can pull signal EN_VBAT2_MEAS low, thus turning on MOSFET Q4. This allows the voltage from BT2 to reach the voltage divider created by R34/R38. The ratio of these two resistors divides the BT2 voltage by a factor of 1.7 and then supplies this voltage to the ADC. The voltage divider keeps the BT2 voltage from saturating the ADC input.

5A-5B show the electrochemical voltage recovery characteristics of a lithium coin backlight cell according to aspects defined herein. For example, if the backlight battery is loaded to 0.8V, when the load is removed, FIG. 5A shows that the voltage begins to recover above 2V after about 60 seconds. However, recovery to 99% of the nominal battery voltage of 3V, for example, may take about 3 hours, as shown in FIG. 5B.

For example, a particular battery model may be selected for use in a portable test meter as a backlight battery. Such batteries can be characterized through factory testing to determine the amount of time it takes for the battery to return to electrochemical equilibrium after being withdrawn over a period of typical use of a portable test meter. can. For a portable glucose test meter that is typically used 3-4 times a day for about 2-5 minutes at a time, the battery cycle is 5 minutes at full withdrawal to determine the time required for recovery. , can be characterized.

In particular, lithium coin batteries displaying the characteristics of FIGS. 5A-5B are not ideal for powering backlight batteries in devices that are operated continuously for relatively long periods of time. However, because test meters, such as glucose meters, are typically used several times a day and for relatively short periods of time during the testing process, lithium coin batteries are well suited for monitoring technology as described herein. can be used as a backlight battery in such instruments. These monitoring techniques allow dead batteries to be detected and replaced in a timely manner.

In addition to recovery time characteristics, a battery may exhibit a voltage drop when stored at temperatures outside its normal operating range. In such cases, the battery is well below its nominal operating temperature, but the techniques described herein may account for the temperature being out of operating range by withholding battery depletion messages during such cycles. .

FIG. 6 is a diagram for monitoring the status of the backlight battery 52 of the portable test meter 10, 10' of FIGS. 1A or 1B when using a backlight battery with characteristics similar to those of FIGS. shows a method 600 of As previously mentioned, test meters, such as glucose meters, include periodic measurements taken over a 24 hour period based on meals and other events (exercise, sleep, etc.). Thus, the test meter is not powered all the time, glucose measurements can be obtained several times during a given 24 hour period, and measurements can often be taken in less than a minute. For purposes of the present invention and for determining backlight battery depletion, it has been found that the test meter off-time is an important factor that can be utilized to determine whether the backlight battery is depleted. found out. In describing the method 600, a specific working example will be provided for illustrative purposes only.

In one embodiment, the method 600 at block 610 measures the off-time of the meter and compares the measured off-time of the meter to a predetermined recovery time of the backlight battery. For example, controller 38 may store backlight usage records in non-volatile memory. In the illustrative working example that follows now with respect to FIG. 6, the record may indicate that the backlight was last energized on day X at 1:08 PM. Then, the next time the meter is turned on, the meter can obtain the current system time from the controller's on-board clock. In a specific working example, the current system time may be Day X at 5:28 PM. The controller can then determine the off time by subtracting the last power up time from the current system time, which in this specific working example is 4 hours and 20 minutes.

To accurately determine whether a test meter's containing battery is dead, the measurement is most accurate when the battery is allowed to recover from periodic cycling. In such a case, the method 600 at block 620 determines whether the off time of the meter is greater than the predetermined recovery time of the backlight battery. In a specific working example, a lithium coin battery may require 4 hours of time to recover, so in this specific example, the controller compares the actual off time to the recovery time of 4 hours. , the YES branch of block 620 can be taken down. Alternatively, if the battery has not fully recovered for the full four hours, at block 620 the method 600 proceeds to block 690 and no warning message is displayed. In such cases, the meter may proceed to the main meter routine so that a test, such as a blood glucose test, is performed.

In another example, a battery may require from 10 minutes to 12 hours to recover. The recovery time for a particular battery model used in a particular test meter may be characterized and an appropriate value for recovery time thus predetermined. Characterization of the recovery time of the battery may be done by controlled testing with N battery replicates and measurement of the internal voltage of the battery with a voltmeter, as described with respect to FIGS. 5A-5B.

Continuing, the method 600 at block 630 turns on (energizes) the backlight of the test meter and measures the voltage of the backlight battery at a predetermined time after the backlight is energized. The predetermined time may be selected to allow the backlight to fully energize before taking measurements. In a specific working example, the battery monitoring circuit 410 can read the voltage after a predetermined time, and the controller can store the voltage in non-volatile memory. For a given period of time, a high-speed voltmeter was used in a controlled environment to monitor the backlight battery voltage during the first few seconds of backlight operation and determine how long it took for the voltage sag to stabilize. It can be selected by controlled trials to determine if it should.

The method 600 at block 640 then compares the measured voltage to a first predetermined voltage above the threshold voltage of the backlight battery. The first predetermined voltage may be selected as a voltage so high that there is little or no chance that the backlight battery is near depletion. Conversely, the threshold voltage may be chosen as the minimum possible voltage required to energize the backlight. In one embodiment, the threshold voltage can be 0.8V and the first predetermined voltage can be 2.5V (the voltage of a new battery).

The method 600 at block 650 determines whether the measured voltage is less than the first predetermined voltage. If the measured voltage is greater than or equal to the first predetermined voltage, method 600 proceeds to block 690 and no warning is displayed. The reason is that the backlight battery is not nearing depletion. In one example, the first predetermined voltage may be set equal to the full voltage of a newly installed battery.

If the method 600 at block 650 determines that the measured voltage is less than the first threshold voltage, the method 600 proceeds to block 660 and compares the measured voltage to a second predetermined voltage. The second predetermined voltage is between the first predetermined voltage and the threshold voltage. The second predetermined voltage may be selected through N (eg, N=100) replicate test meters and controlled testing of the battery. The second predetermined voltage represents the voltage at which the battery is so close to depletion that it requires intervention by the user. For example, the second predetermined voltage can be set through controlled testing to the point that a typical meter test of a certain small number, e.g., 1 to 5 tests, can be performed before the battery is completely depleted. may be determined. In one example, the second predetermined voltage can be between 1.0V and 1.2V.

The method 600 at block 670 determines whether the measured voltage is less than the second predetermined voltage. If the measured voltage is not less than the second predetermined voltage, the method proceeds to block 690 and no warning is displayed.

Conversely, if the measured voltage is less than the second predetermined voltage, the method proceeds to block 690 and a low battery warning or message is displayed on the meter. In one example, the battery depletion message may be continuously displayed on the meter as a low battery icon. In another example, the meter may require confirmation of a low battery warning before allowing the test to run. In a further example, a low battery warning can indicate the number of test cycles remaining in the meter. In yet another example, a low battery warning may be escalated or repeated based on how few typical tests remain.

In another embodiment, the method may measure a second voltage of the backlight battery at a second predetermined time. For example, the second voltage may be obtained by measuring 1 second to 1000 seconds after measuring the first voltage. The second voltage measured may be used to determine the voltage drop across the battery that occurs during a predetermined time period after the backlight is energized. As the backlight battery dies, this voltage drop increases with each cycle of use. In examples using low capacity batteries to power the backlight, such batteries may power the backlight for a certain duration before needing to be turned off for a recovery cycle. Thus, the meter can determine that if the backlight has been powered for longer than a certain time interval and cannot be recovered, the battery is only temporarily depleted rather than permanently depleted. Again, the acceptable on-time of such batteries can be characterized by controlled testing of N replicate meters with the batteries.

In particular, the method 600 described above with respect to blocks 610-680 is typically performed before a meter user performs a test on the meter. Accordingly, a user may receive a backlight battery warning, at which time they may decide to forego conducting a test, such as a self-monitoring blood glucose test, and replace the backlight battery immediately. In another example, the user may choose to run the test first and then replace the backlight battery. In yet another embodiment, based on the voltage level of the battery after energizing the backlight, the controller estimates the typical number of test cycles that may remain before the battery is completely unable to illuminate the screen, and A warning can be provided indicating how many more tests are possible before the is completely exhausted.

In another embodiment, in addition to or instead of the battery depletion check described above, a so-called gas gauge technique may be employed, in which the cumulative energy used by the battery over its life is measured by a new battery. is tracked by measuring the voltage and current for each historical time interval in which the meter is used, starting when the is attached to the system. Using such a technique alone is prone to error because a partially charged battery may be installed in the test meter. However, in combination with other monitoring described above, such techniques can eliminate false positives and false negatives. For example, if a known new battery is installed (e.g., a smart battery with a specific identification code that indicates the manufacturer), the meter uses accumulated usage data to disable low battery warnings. be able to.

Although the present invention has been described with respect to certain variations and exemplary drawings, those skilled in the art will recognize that the present invention is not limited to the variations or drawings described. Additionally, where the methods and steps described above indicate that certain events occur in a certain order, it will be appreciated by those skilled in the art that the order of certain steps may be altered, and such alterations are variations of the invention. You will also recognize that it is by example. Moreover, certain of the steps may be performed concurrently in parallel processes where possible, as well as performed in the order described above. Therefore, to the extent there are variations of the invention that are within the spirit of this disclosure or that are equivalent to the invention found in the claims, this patent is intended to cover those variations as well. intended.

To the extent a claim recites the phrase "at least one of" in reference to multiple elements, this is intended to mean at least one or more of the listed elements, and at least one of each element It is not limited to one. For example, "at least one of element A, element B, and element C" is intended to refer to element A alone, or element B alone, or element C alone, or any combination thereof. "At least one of element A, element B, and element C" is not intended to be limited to at least one of element A, at least one of element B, and at least one of element C.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use any device or system, or to practice any incorporated method. It enables the present invention to be practiced. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples, if they have structural elements that do not differ from the language of the claims, or if they contain equivalent structural elements that do not differ substantially from the language of the claims, are not subject to the scope of the claims. intended to be contained within

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a, an" and "the" are intended to include plural forms as well, unless the context clearly indicates otherwise. "comprise" (and any form of comprises such as "comprises" and "comprising"), "have" (and have such as "has" and "have" any form of ), "include" (and any form of include such as "includes" and "including"), and "contain" (and "contains" and "containing is further understood to be an open-ended conjunctive verb, such as "comprising", "having", "comprising", "having", one or more steps or elements. A method or apparatus that "comprises" or "contains" includes one or more of those steps or elements, but is not limited to including one or more of those steps or elements. A method step or apparatus element that "comprises," "has," "includes," or "contains" the features of the Furthermore, a device or structure configured in a particular way may be configured in at least that way, but may be configured in ways not listed.

Corresponding structures, materials, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims, if any, are specifically claimed in other claims Intended to include any structure, material, or act to perform a function in combination with the elements. The description set forth herein has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. Although the embodiment was chosen and described, it best illustrates the principles and practical application of one or more aspects described herein and is suitable for the particular uses contemplated by others skilled in the art. This is to enable an understanding of one or more aspects described herein for various embodiments with various modifications.

Claims (20)

a meter housing;
a controller;
a display on the meter housing, the display comprising a thin film transistor (TFT) screen and backlight;
a backlight battery operably connected to the backlight;
a battery monitoring circuit operatively connected to the controller and the backlight battery, the battery monitoring circuit comprising:
measuring the off-time of the portable test meter and comparing the measured off-time of the portable test meter to a predetermined recovery time of the backlight battery;
If the off-time of the portable test meter is greater than the predetermined recovery time of the backlight battery, measuring the voltage of the backlight battery at a predetermined time after energizing the backlight, and measuring the measured voltage. to a first predetermined voltage, wherein the first predetermined voltage exceeds a threshold voltage of the backlight battery;
comparing the measured voltage to a second predetermined voltage if the measured voltage is less than the first predetermined voltage, wherein the second predetermined voltage is the first predetermined voltage and the is between the threshold voltages;
displaying a low battery warning if the measured voltage of the backlight battery is less than the second predetermined voltage;
A portable test instrument that performs The backlight battery is configured to be periodically loaded for a power-on time followed by the predetermined recovery time such that loading the backlight battery for a period longer than the power-on time causes internal 2. The portable test meter of claim 1, wherein the voltage drops below the threshold voltage of the backlight battery. The battery monitoring circuit measures a second voltage of the backlight battery at a second predetermined time before energizing the backlight, and measures a second voltage of the backlight battery at the predetermined time and the second predetermined time. 2. The portable test meter of claim 1, further configured to display a low battery warning on a screen of the portable test meter in response to the voltage comparison. 2. The handheld test meter of claim 1, wherein the predetermined time period is between 1 millisecond and 1000 milliseconds. The battery monitoring circuit measures cumulative power consumption of the backlight battery during a power-on operation of the backlight, and when the measured cumulative power consumption is below a predetermined rated power of the backlight battery, the battery 3. The portable test meter of claim 1, displaying a depletion warning. 2. The handheld test of claim 1, wherein the battery monitoring circuit measures the temperature of the backlight battery and displays the low battery warning when the temperature is within a predetermined operating temperature range of the backlight battery. measuring instrument. The portable test meter of Claim 1, wherein the backlight battery is a lithium primary battery. 2. The portable test meter of claim 1, further comprising a main battery operably connected to said controller and said TFT screen, said main battery and said backlight battery being the same type of battery. A method for monitoring a backlight battery status of a portable test meter, said portable test meter comprising a meter housing, a controller, and a display on said meter housing, said The display comprises a TFT screen and a backlight, said backlight powered by said backlight battery, said method comprising:
measuring the off-time of the portable test meter and determining whether the off-time is greater than a predetermined recovery time of the backlight battery;
energizing the backlight;
measuring the voltage of the backlight battery at a predetermined time after energizing the backlight if the off time of the portable test meter is longer than the predetermined recovery time of the backlight battery;
comparing the measured voltage to a first predetermined voltage, wherein the first predetermined voltage exceeds a threshold voltage of the backlight battery;
if the measured voltage is less than the first predetermined voltage, comparing the measured voltage to a second predetermined voltage, wherein the second predetermined voltage is the first predetermined voltage and the a step that is between a threshold voltage;
displaying a low battery warning on the TFT screen of the portable test meter if the measured voltage of the backlight battery is less than the second predetermined voltage;
A method, including further comprising periodically loading the backlight battery for a power-on time followed by the predetermined recovery time, wherein loading the backlight battery for a period longer than the power-on time causes the backlight to 10. The method of claim 9, wherein the internal voltage of the battery drops below said threshold voltage. 10. The method of claim 9, further comprising measuring a third voltage of the backlight battery prior to energizing the backlight. 2. The method of claim 1, further comprising displaying a low battery warning on the TFT screen of the portable test meter. 10. The method of claim 9, wherein the predetermined time is between 1 millisecond and 1000 milliseconds. 10. The method of claim 9, further comprising measuring cumulative power consumption of the backlight battery during power up operation of the backlight. 15. The method of claim 14, further comprising displaying the low battery warning when the measured cumulative power consumption is below a predetermined power rating of the backlight battery. 10. The method of claim 9, further comprising measuring the temperature of the backlight battery. 17. The method of claim 16, further comprising displaying the low battery warning when the temperature is within a predetermined operating temperature range of the backlight battery. 10. The method of claim 9, wherein the backlight battery is a lithium primary battery. 10. The method of claim 9, further comprising a main battery operatively connected to the controller and the TFT screen, wherein the main battery and the backlight battery are the same type of battery. 3. The portable test meter of claim 1, wherein the portable test meter is used to periodically measure a patient's blood glucose level.

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