JP2024001216A - Portable test meter with backlight battery depletion monitoring - Google Patents

Abstract

To provide a test meter and a related method for monitoring the condition of a backlight battery of the meter, where the meter includes a housing, a controller, a display with a backlight, and a battery monitoring circuit.SOLUTION: An 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, a voltage of the backlight battery is measured at a predetermined time after energizing the backlight, and the measured voltage is compared to a first predetermined voltage in excess of a threshold voltage of the backlight battery. If the measured voltage is less than the first predetermined voltage, the measured voltage is compared to a second predetermined voltage between the first predetermined voltage and the threshold voltage. A battery depletion warning is displayed if the measured voltage is less than the second predetermined voltage.SELECTED DRAWING: Figure 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 test objects and battery depletion used in the portable test meters. and related methods for monitoring.

Handheld devices, such as portable test meters, typically require a display to communicate the results of the test measurements to the user of the test meter. Such displays may include a backlight for ease of reading in dark locations. What is desired is a portable test and measurement instrument that is compact, lightweight, and long-lasting without requiring 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 backlighting, making them unsuitable for use in portable test instruments that operate for weeks or months without battery changes. The reason is that the backlight cannot be disabled to save power. Therefore, such displays, which require constant backlighting, are typically not utilized or considered for use in such portable test and measurement instruments.

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

Additionally, commonly used battery depletion detection algorithms can only see the battery voltage before startup. In such cases, the effects of battery internal resistance, ion mobility, and temperature are not considered. However, such a simple test works, but only for cells that are subject to relatively small and stable current drains.

In order that the features of the invention may be understood, a detailed description can be obtained by reference to specific embodiments, some of which are illustrated in the accompanying drawings. The drawings, however, are only illustrative of particular embodiments and therefore should not be considered as limiting the scope of the disclosed subject matter, as it also encompasses other embodiments. Please note that. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating features of particular embodiments. In the drawings, like numerals are used to indicate like parts throughout the various figures.

FIG. 3 illustrates a partially exploded rear view of a portable test meter in accordance with aspects described herein. 1 illustrates a front view of a portable test meter according to aspects described herein. FIG. 1B is a block diagram of a controller used and powered by the portable test and measurement instrument of FIG. 1A; FIG. 2B is a plan view of a circuit board containing electrical components of the portable test and measurement instrument 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 drive circuit with a battery monitoring circuit in accordance with aspects described herein for use in a test meter. 2 illustrates voltage recovery characteristics of a battery intended for use as a backlight battery in a test meter, according to embodiments described herein. 2 illustrates voltage recovery characteristics of a battery intended for use as a backlight battery in a test meter, according to embodiments described herein. 5A-5B illustrate a method for monitoring the condition 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.

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 are not necessarily to scale and depict selected embodiments and are not intended to limit the scope of the invention. The detailed description is intended to illustrate, by way of example and not by way of limitation, the principles of the invention. This description clearly enables those skilled in the art to make and use the invention, and describes several embodiments, applications, variations, alternatives, and uses of the invention, some of which include: It also includes what is currently considered to be the best mode for carrying out the invention.

As used herein, the term "about" or "approximately" in reference to any numerical value or range thereof means that a portion or collection of the components functions in accordance with the intended purpose set forth herein. Indicate appropriate dimensional tolerances to allow for Additionally, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject for which the system or method is used in humans. Although not intended to be limiting, use of the subject technology in human patients represents a preferred embodiment.

The present disclosure relates, in part, to portable test meters such as those used to periodically measure blood glucose levels in a subject. Some of these test meters include a mains electrically powering the controller and display included in the test meter, along with optional measurement subsystems such as electrochemical test circuits for monitoring blood glucose. Equipped with a battery or primary battery. In the case of 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 may further include a dedicated backlight battery, and battery monitoring may be enhanced to facilitate replacement of the backlight battery before it becomes depleted. More specifically, the main battery may be used to power the test instrument's controller, display logic, and any measurement subsystems, and the dedicated backlight battery may only be used to power the backlight. may be used. Such a configuration allows the use of TFT displays in portable test and measurement instruments despite the problem that TFT displays require backlighting for viewing. In one embodiment, the footprint of a portable test meter is reduced by using a conventional coin cell as a backlight-only battery. This is because coin cells, which cannot normally be used in backlights, operate in a non-conventional manner as described herein.

Additionally, coin-shaped batteries, such as CR2032 lithium batteries, have been commonly used in portable test and measurement 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 specific usage patterns of portable test meters, such as those used regularly to measure blood sugar in diabetic patients.

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. The test meter includes, for example, a housing that holds a controller for periodically measuring a subject's blood glucose level. The test meter further includes a display, such as a TFT display with a backlight, and circuitry for monitoring a dedicated backlight battery. Using this monitoring circuit, 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 measuring device is longer than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after energizing the backlight, 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, the measured voltage is compared to a second predetermined voltage between the first predetermined voltage and a threshold voltage. If the measured voltage is less than a second predetermined voltage, a battery depletion warning is displayed.

In another embodiment, this disclosure discloses a method for monitoring the status of a backlight battery of a portable test meter. The test meter includes a meter housing that holds a number of components including a controller, and a display is provided on 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 measuring device is longer than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after energizing the backlight, 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, the measured voltage is compared to a second predetermined voltage between the first predetermined voltage and the threshold voltage. If the measured voltage is less than a second predetermined voltage, a battery depletion warning is displayed.

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

Next, a specific example of work will be explained. Portable test meters and battery monitoring techniques will first be described in conjunction with FIGS. 1-6.

FIG. 1A shows a rear view of a portable test meter 10 defined by a meter housing 11 that 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, a display 14 according to this embodiment includes a thin film transistor (TFT) screen and a backlight and is located on the front side of a similar portable test and measurement instrument 10'. In one operational example, the main battery 50 powers not only the controller 38 but also the TFT display logic. On the other hand, the backlight battery 52 supplies power only to the display backlight.

Depending on the configuration, the backlight can be a light emitting diode (LED) or an array of LEDs, and the array can include 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 located within the housing 11 of the test meter 10, 10' of FIGS. 1A and 1B. It may 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. Although the portable test meters 10, 10' have different physical appearances, they generally operate in the same manner. Note that the measuring device (measuring device unit) is sometimes 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 a cable or via a suitable wireless technology such as eg GSM, CDMA, Bluetooth, WiFi. Such a management system is described in more detail in U.S. Pat. Incorporated herein.

Returning to FIG. 1B, the glucose meter or meter unit 10' is defined by a housing 11 having a plurality of user interface buttons (16, 18, 20) disposed on facing surfaces of the housing 11. Display 14 is provided in addition to a 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 user interface buttons can take on a variety of configurations, and the three interface buttons depicted are one example. The data may include values representative of analyte concentrations and/or information related to the individual's daily life. Information regarding daily life may include an individual's dietary intake, medication status, health checkup status, health status, and exercise level. The electronic components of the portable test meter 10, 10' may be located on a circuit board 34 (FIG. 2B) located 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. FIG. Controller 38 includes a central processing unit (CPU) 212, random access memory (RAM) 214, an 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. GPIO 218 can communicate with a display to turn on backlight 60 (see FIG. 3) or with a 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, operational amplifier circuit 35, controller 38, display connector 14a, non-volatile memory 40, clock 42, and first wireless 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 a test strip port connector 22, an operational amplifier circuit 35, a first wireless module 46, a display 14, a non-volatile memory 40, a clock 42, at least one battery, a data port 13, and user interface buttons 16, 18, 20. may be electrically connected to.

Op amp circuit 35 may include two or more op amps configured to provide some of the potentiostat functionality and current measurement functionality. 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. Current function may refer to the measurement of test current resulting from an applied test voltage. Current measurements may be performed using a current-to-voltage converter. Controller 38 may, for example, be in the form of a mixed signal microprocessor (MSP), such as the Texas Instrument MSP430. The TI MSP430 may also be configured to perform some of the potentiostat functions 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 14a may be configured to attach to display 14. Display 14 may be in the form of a liquid crystal display for reporting measured glucose levels and for facilitating input 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 accept a suitable connector attached to a connecting lead (not shown), thereby allowing test meter 10 to be linked to an external device such as a personal computer. Data port 13 may be any port that allows the transmission of data, such as a serial, USB, or parallel port. Clock 42 may be configured to keep a current time and measure time relative to the geographic region in which the user is located, 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 the test meter 10 of FIG. In this configuration, the controller 38 is connected to a main battery 50 for supplying power to the controller 38. The backlight battery 52 is used to power the backlight 60 of the display 14 via the backlight drive circuit 54.

FIG. 4 illustrates a backlight drive circuit 410 according to an embodiment, as used with a battery monitoring circuit 420. The exemplary backlight drive 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, can be maintained at pin FB of U10 to provide an LED drive current of about 10 mA. Battery monitoring circuit 420 measures voltage VBAT2 via an analog-to-digital converter (ADC). For example, to facilitate backlight battery measurements, the controller may pull signal EN_VBAT2_MEAS to a low potential, 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 prevents the BT2 voltage from saturating the ADC input.

5A-5B illustrate electrochemical voltage recovery characteristics of a lithium coin backlight cell according to embodiments 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 to above 2V after about 60 seconds. However, recovery to 99% of the nominal battery voltage of, for example, 3V may take approximately 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 cells may be characterized through factory testing to determine the amount of time it takes for the cell to return to electrochemical equilibrium after being drawn out for a period of typical use of a portable test meter. can. For portable glucose test meters that are typically used for about 2 to 5 minutes at a time, 3 to 4 times a day, the battery cycle is 5 minutes at full draw to determine the time needed 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 during the testing process for relatively short periods of time, lithium coin batteries are not suitable for monitoring techniques such as those described herein. can be used as a backlight battery in such measuring instruments. These monitoring techniques allow depleted 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 the nominal operating temperature, but the techniques described herein may account for the temperature being outside the operating range by refraining from 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 FIG. 1A or FIG. 1B when using a backlight battery having characteristics similar to those of FIGS. 5A and 5B. 600 shows a method 600. As previously mentioned, test meters, such as glucose meters, involve periodic measurements taken during a 24-hour period based on meals and other events (exercise, sleep, etc.). Thus, the test meter is not constantly powered, and 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 to determine backlight battery depletion, the off time of the test meter is an important factor that can be utilized to determine whether the backlight battery is depleted. Found out. In describing method 600, specific working examples are provided for purposes of illustration 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 here with respect to FIG. 6, the record may show that the last time the backlight was energized was on day X at 1:08 p.m. Then, the next time the meter is turned on, the meter may obtain the current system time from the controller's onboard clock. In a specific working example, the current system time may be 5:28 PM on day X. The controller can then determine the off time by subtracting the last energization time from the current system time, which in this specific working example is 4 hours and 20 minutes.

To accurately measure whether the test meter's house battery is depleted, the measurement will be 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 meter off time is greater than a predetermined recovery time of the backlight battery. In a specific working example, a lithium coin battery may require a time of 4 hours to recover, so in this specific example, the controller compares the actual off time with the recovery time of 4 hours. , the YES branch of block 620 can be followed down. Alternatively, if the battery is not able to fully recover for the full four hours, then at block 620 the method 600 proceeds to block 690 and no warning message is displayed. In such case, the meter may proceed with the main meter routine and allow a test, such as a blood glucose test, to be performed.

In another example, a battery may require 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 battery recovery time may be done by controlled testing with N battery replicates and measurement of the battery's internal voltage using 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 energizing the backlight. The predetermined period of time may be selected to fully energize the backlight before taking measurements. In a specific working example, the battery monitoring circuit 410 can read the voltage after a predetermined period of time, and the controller can store the voltage in non-volatile memory. For a given time, use a high-speed voltmeter in a controlled environment to monitor the backlight battery voltage during the first few seconds of backlight operation and determine how much time has passed for the voltage drop to stabilize. can be selected by controlled trials to determine whether

Next, the method 600 at block 640 compares the measured voltage to a first predetermined voltage that exceeds a threshold voltage of the backlight battery. The first predetermined voltage may be selected to be such a voltage that there is little or no possibility that the backlight battery will be near depletion. Conversely, the threshold voltage may be selected as the minimum possible voltage required to energize the backlight. In one embodiment, the threshold voltage may be 0.8V and the first predetermined voltage may be 2.5V (new battery voltage).

The method 600 at block 650 determines whether the measured voltage is less than a 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 close to being depleted. In one example, the first predetermined voltage may be set equal to the total voltage of the 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 controlled testing of N (eg, N=100) replicate test meters and batteries. The second predetermined voltage represents a voltage at which the battery is nearing depletion to require intervention by the user. For example, the second predetermined voltage may be applied through a controlled test to the point that the battery may perform a typical meter test a certain small number of times, e.g., 1 to 5 tests, before being 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 a 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 a 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 may display the number of test cycles remaining for the meter. In yet another example, the battery depletion 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 measured second voltage may be used to determine a battery voltage drop that occurs during a predetermined period of time after energizing the backlight. As the backlight battery becomes depleted, this voltage drop increases with each usage cycle. In an example of using a low capacity battery to power the backlight, such a battery may power the backlight for a specified duration before it needs to be turned off for a recovery cycle. Therefore, if the backlight is powered for longer than a certain time interval and cannot be recovered, the instrument can determine that the battery is not permanently depleted, but only temporarily depleted. Again, the acceptable on-time of such a battery can be characterized by controlled testing of N replicate instruments with the battery.

In particular, the method 600 described above with respect to blocks 610-680 is typically performed before a user of the meter performs a test on the meter. Accordingly, the user may receive a backlight battery warning and may decide at that time to forego performing a test, such as a self-monitoring blood glucose test, and immediately replace the backlight battery. In another example, a user may choose to perform a 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 number of typical test cycles that may remain before the battery is unable to fully illuminate the screen, and A warning can be provided indicating how many trials are left before the test 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 a battery during its lifetime is determined by a new battery. The meter is tracked by measuring voltage and current for each historical time interval that the meter is used, starting when it is installed in the system. The use of such techniques alone is prone to errors because a partially charged battery may be installed in the test meter. However, in combination with other monitoring mentioned 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 indicating the manufacturer), the meter will use the accumulated usage data to override the battery depletion warning. be able to.

Although the invention has been described with respect to particular variations and exemplary drawings, those skilled in the art will recognize that the invention is not limited to the variations or drawings described. In addition, where the methods and steps described above indicate that certain events occur in a certain order, those skilled in the art will also recognize that the order of the certain steps may be changed and that such changes may be considered variations of the present invention. You will also recognize that this is by example. Additionally, certain of the steps may not only be performed in the order as described above, but also simultaneously in parallel processes where possible. Accordingly, this patent is intended to cover variations of the invention to the extent that there are variations of the invention that fall within the spirit of the disclosure or are equivalent to the invention found in the claims. intended.

To the extent that the claims recite the phrase "at least one of" with respect to multiple elements, this is intended to mean at least one or more of the listed elements, and at least one of each element. Not limited to one. For example, "at least one of element A, element B, and element C" is intended to refer to element A only, or element B only, or element C only, 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 explain how any person skilled in the art can make and use any apparatus or system or carry out any method employed. This will enable the present invention to be implemented. 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 do not apply to the present claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not materially differ from the language of the claims. intended to be included 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 the plural forms as well, unless the context clearly dictates otherwise. "comprise" (and any form of "comprise" as in "comprises" and "comprising"), "have" (as in "has" and "having") ), "include" (and any form of include, such as "includes" and "including"), and "contain" (as well as "contains" and "containing"). Any form of the term contain is further understood to be an open-ended linking verb, such as "comprising," "having," or "having" one or more steps or elements. A method or apparatus that "comprises" or "contains" retains one or more steps or elements thereof, but is not limited to retaining one or more of those steps or elements. Similarly, one or more An element of a method step or apparatus that "comprises," "has," "includes," or "contains" retains one or more of those characteristics, but retains one or more of those characteristics. Further, a device or structure configured in a particular manner may be configured in at least that manner, but may also be configured in ways not listed.

Corresponding structures, materials, acts, and equivalents of all means-plus-function or step-plus-function elements of the following claims, if any, are covered by other specifically claimed claims, if any. Intended to include any structure, material, or act that, in combination with the elements, performs a function. The description herein is presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments have been selected and described to best explain the principles and practical application of one or more aspects described herein, and that others skilled in the art will understand as suitable for the particular use contemplated. This is provided to provide an understanding of one or more aspects described herein with various modifications.

Claims (20)

a measuring instrument housing;
controller and
a display on the meter housing, the display comprising a thin film transistor (TFT) screen and a backlight;
a backlight battery operably connected to the backlight;
a portable test and measurement instrument comprising: a battery monitoring circuit operably connected to the controller and the backlight battery, the battery monitoring circuit comprising:
measuring an 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 longer than the predetermined recovery time of the backlight battery, measure the voltage of the backlight battery at a predetermined time after energizing the backlight, and and 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 with a second predetermined voltage, the second predetermined voltage being equal to the first predetermined voltage. between the threshold voltages; and
displaying a battery depletion warning when the measured voltage of the backlight battery is less than the second predetermined voltage;
A portable test measuring instrument that performs The backlight battery is configured to be loaded periodically over a power-up time followed by the predetermined recovery time, and loading the backlight battery for a period longer than the power-up time causes internal battery damage. 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. 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. The portable test and measurement instrument according to claim 1, wherein the predetermined time 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 less than a predetermined rated power of the backlight battery, the battery monitoring circuit measures the cumulative power consumption of the backlight battery during a power-on operation of the backlight. The portable test meter of claim 1, which displays a depletion warning. The portable test according to claim 1, wherein the battery monitoring circuit measures the temperature of the backlight battery and displays the battery depletion warning when the temperature is within a predetermined operating temperature range of the backlight battery. Measuring instrument. The portable test and measurement instrument according to claim 1, wherein the backlight battery is a lithium primary battery. The portable test and measurement instrument of claim 1, further comprising a main battery operably connected to the controller and the TFT screen, wherein the main battery and the backlight battery are the same type of battery. A method for monitoring the status of a backlight battery of a portable test meter, the portable test meter comprising: a meter housing; a controller; a display on the meter housing; The display comprises a TFT screen and a backlight, the backlight is powered by the backlight battery, and the method includes:
measuring an 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;
If the off time of the portable test meter is longer than the predetermined recovery time of the backlight battery, measuring the voltage of the backlight battery at a predetermined time after energizing the backlight;
comparing the measured voltage to a first predetermined voltage, the first predetermined voltage being above a threshold voltage of the backlight battery;
If the measured voltage is smaller than the first predetermined voltage, comparing the measured voltage with a second predetermined voltage, the second predetermined voltage being the first predetermined voltage and the first predetermined voltage. a step between the threshold voltages;
if the measured voltage of the backlight battery is less than the second predetermined voltage, displaying a battery depletion warning on the TFT screen of the portable test meter;
including methods. further comprising periodically loading the backlight battery over a power-up time followed by the predetermined recovery time, wherein loading the backlight battery for a time longer than the power-up time causes the backlight to 10. The method of claim 9, wherein the internal voltage of the battery is reduced below the threshold voltage. 10. The method of claim 9, further comprising measuring a third voltage of the backlight battery before 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 a power-up operation of the backlight. 15. The method of claim 14, further comprising displaying the battery depletion 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 battery depletion 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 operably connected to the controller and the TFT screen, the main battery and the backlight battery being the same type of battery. 2. The portable test meter of claim 1, wherein the portable test meter is used to periodically measure a patient's blood glucose level.