HK1200215B - Rapid charging of a battery-powered fluid analyte meter - Google Patents

Description

Fast charging of battery-powered liquid analyzers

The present application is a divisional application of patent application No. 200880120042.1 entitled "rapid charging and power management of a liquid analyzer powered by a battery" filed on 2008/29.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. patent application 61/012,690, filed on 10/12/2007, which is hereby incorporated by reference in its entirety.

Technical Field

The present invention relates generally to test sensors powered by rechargeable batteries, and more particularly to rapid charging of battery-powered sensors.

Background

The detection of the amount of an analyte in a body fluid is of great importance in the diagnosis and maintenance of certain physical conditions. For example, lactate, cholesterol, and bilirubin should be monitored in certain individuals. In particular, for diabetic patients, it is important to determine the glucose in body fluids, since they must frequently detect the glucose level in body fluids in order to control the glucose intake in the diet. These measurements can be used to determine which insulin or other medication to take if desired. In a testing system, a test sensor is used to test a liquid, such as a blood sample.

Many people test their blood glucose many times a day. Therefore, these people often must carry with them a meter to determine the glucose concentration in their blood. They may also carry with them other analytical test instruments including test sensors, lancets, disposable lancets, syringes, insulin, oral medications, paper towels, etc. to enable blood glucose testing at various locations including their home, place of work (e.g., office building or construction site), entertainment venues, etc. However, it may be inconvenient to carry the meter and/or other analytical test instruments to the various locations.

The glucose meter may be powered by various types of power supply arrangements, such as batteries or a power adapter that may be plugged into a standard outlet. The battery is used to make the device portable and mobile without power socket. Batteries that can be used in blood glucose meters include both disposable and rechargeable batteries. Rechargeable batteries are used for blood glucose meters, and the batteries need to be charged to operate the blood glucose meter. Sometimes when the battery is dead, a critical situation may arise that requires an urgent measurement of blood glucose.

The measurement of blood glucose concentration is typically based on a chemical reaction between blood glucose and a reagent. Chemical reactions and blood glucose readings measured by a blood glucose meter are temperature sensitive, and therefore, a temperature sensor is typically placed within the blood glucose meter. The calculation of blood glucose concentration by these meters typically assumes that the temperature of the reagent is equal to the temperature read from the sensor placed within the meter. However, if the actual temperatures of the reactants and the meter are different, the calculated blood glucose concentration will be inaccurate. The rise in temperature or the presence of a heat source within the glucose meter will typically cause an erroneous measurement of glucose.

Power management in battery powered glucose meters may include monitoring the state of battery charge with a battery fuel gauge. Battery meters typically continuously monitor the current flowing bi-directionally through the battery of the glucose meter. However, such continuous monitoring also requires that the battery fuel gauge is always on, which results in increased power consumption even when the battery-powered blood glucose meter is in a sleep mode. Increased power consumption requires larger size batteries and increases battery cost, especially for portable devices.

It is therefore desirable to have a battery powered meter that can be charged quickly without significant temperature rise. It is also desirable to manage power consumption of battery powered meters to minimize power consumption during periods of inactivity and to maintain accurate assessment of battery state of charge.

Disclosure of Invention

According to one embodiment, a battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising: a front end portion having a display for displaying the analyte concentration of the liquid sample; a user interaction mechanism for controlling the meter; a housing defining an area for receiving a rechargeable battery and defining a port sized to receive at least a portion of a test sensor; a temperature sensor disposed within the housing; and a microprocessor disposed within the housing, the microprocessor for performing a fast charging process associated with the rechargeable battery, the process comprising the steps of: (i) monitoring a connection to an external power source; and (ii) in response to receiving identification information of the connection to the external power source, perform a charging process for rapidly charging the battery at a first charging rate until a threshold temperature determined with the temperature sensor is exceeded; subsequently, the battery is charged at a second charge rate, the second charge rate being lower than the first charge rate, wherein execution of the charging process results in a negligible temperature rise within the rechargeable battery caused by the first and second charge rates, thereby limiting the temperature effect in determining the concentration of the liquid analyte.

According to another embodiment, a method of rapidly charging a battery in a meter having a port capable of receiving at least a portion of a test sensor, the meter for determining a liquid analyte concentration of a liquid sample, the method comprising the steps of: determining a temperature based on temperature data associated with a temperature sensor disposed within the meter; in response to receiving an input relating to the connection of the meter to the external power source, performing a fast charge process for charging the battery at a first charging current until a threshold temperature value determined in the determining a temperature step is exceeded; in response to the threshold temperature value being exceeded, performing a normal charging process for charging the battery at a second charging current, the second charging current being lower than the first charging current, wherein the performing of the rapid charging process and the normal charging process results in a negligible temperature rise within the battery caused by the first charging current and the second charging current, thereby limiting temperature effects in determining liquid analyte concentration.

According to yet another embodiment, a battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising: a housing defining an area for receiving a rechargeable battery and defining a port sized to receive at least a portion of a test sensor; a slave and a microprocessor disposed within the housing, the microprocessor for performing a fast charge process associated with the rechargeable battery, the fast charge process comprising the steps of: (i) monitoring the residual battery capacity of the rechargeable battery, which is less than the preset capacity; and (ii) in response to the rechargeable battery falling below the preset charge level, performing a charging process to charge the rechargeable battery at a 2C to 5C charge rate in one minute, wherein the determination of analyte concentration by the meter has an estimated energy consumption, the performance of the charging process providing energy to the rechargeable battery to allow completion of the determination of one or more analyte concentrations based on the estimated energy consumption, the charging process further minimizing temperature rise within the rechargeable battery, thereby limiting temperature effects in determining liquid analyte concentrations.

According to yet another embodiment, a battery-powered meter is adapted to determine an analyte concentration of a liquid sample, the meter comprising: a front end portion having a display for displaying the analyte concentration of the liquid sample; a user interaction mechanism for controlling the meter; a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of: (i) monitoring a connection to an external power source; and (ii) in response to receiving identification information of the connection to the external power source, performing a charging process for rapidly charging the battery at a first charging rate until a first preset event occurs; subsequently, the battery is charged at a second charge rate that is lower than the first charge rate, wherein the charging process is performed to minimize a temperature rise in the meter configured for a temperature sensitive analyte concentration test such that the temperature rise is negligible for the temperature sensitive analyte concentration test.

According to another embodiment, a battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising: a front end portion having a display for displaying the analyte concentration of the liquid sample; a user interaction mechanism for controlling the meter; a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of: (i) monitoring a connection to an external power source; and (ii) in response to receiving identification information of the connection to the external power source, performing a charging process for rapidly charging the battery at a first charging rate until a first preset event occurs; subsequently, the battery is charged at a second charge rate, the second charge rate being lower than the first charge rate, wherein the charging process is performed in accordance with a temperature rise condition of the meter in view of the meter being configured for a particular temperature sensitive analyte concentration test.

According to yet another embodiment, a battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising: a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of: (i) monitoring the residual battery capacity of the rechargeable battery, which is less than the preset capacity; (ii) in response to the rechargeable battery being below the preset charge level, performing a fast charge process to charge the rechargeable battery at a charge rate of 2C to 5C in one minute, wherein the determination of analyte concentration by the meter has an estimated energy consumption, and wherein the performing of the fast charge process provides energy to the rechargeable battery to allow completion of the determination of one or more analyte concentrations based on the estimated energy consumption.

Other advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings.

Drawings

FIG. 1a shows a sensor with a cover according to one embodiment.

Fig. 1b shows the sensor of fig. 1a without a cover.

FIG. 2a shows a front view of a meter with a display according to one embodiment.

Figure 2b shows a side view of the meter of figure 2 a.

Fig. 3 shows a charging circuit for a rechargeable battery according to an embodiment.

Fig. 4 shows a charging algorithm with a high temperature rise phase for charging the battery.

Fig. 5 shows a current regulation phase with high and low temperature rise phases according to one embodiment.

Fig. 6 shows a finite state machine of a method of rapidly charging a rechargeable battery with minimal temperature rise according to one embodiment.

Fig. 7 shows a battery charging characteristic diagram according to an embodiment.

FIG. 8 shows a circuit for a meter with a battery fuel gauge and a battery charger according to one embodiment.

FIG. 9 shows a finite state machine of a power management method for a battery-powered device according to one embodiment.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Detailed Description

A system and method for rapid charging of a meter battery is disclosed herein. A critical situation arises if a user requires an emergency test, such as the use of a blood glucose meter, when the rechargeable battery of a battery-powered meter is dead. For meters powered by rechargeable batteries, this critical situation can be minimized. The discharged battery can be charged using a rapid charge technique in a short period of time to provide sufficient power to allow the meter to perform one or more tests (e.g., to analyze blood glucose concentration) while minimizing temperature rise in the meter.

Figures 1a-b and 2a-b show an embodiment of a meter according to the invention, such as a blood glucose meter. These devices may include an electrochemical test sensor for determining the concentration of at least one analyte in a liquid. Analytes that can be determined with the device include glucose, fats (e.g., cholesterol, triglycerides, LDL and HDL), urine microprotein (microalbumin), hemoglobin A₁C(hemoglobin A₁C) Sugar, lactate or bilirubin. However, the invention is not limited to devices that determine these particular analytes, and may determine the concentration of other analytes. The analyte may be present in, for example, a whole blood sample, a serum sample, a plasma sample, or other bodily fluids such as interstitial fluid (ISF) and urine.

Although the meter shown in fig. 1 and 2 is generally rectangular, it should be noted that the cross-section of the meter used herein may be other shapes, such as circular, square, hexagonal, octagonal, other polygonal shapes, or elliptical. The meter is typically made of a polymeric material. Examples of polymeric materials that may be used to make the meter include, but are not limited to, polycarbonate, ABS, nylon, polypropylene, or combinations thereof. It is contemplated that the meter may also be made of a non-polymeric material.

According to certain embodiments, the test sensor of the device is typically equipped with a capillary tube that extends from the front or testing end of the sensor to the biological sensor or reactant disposed in the sensor. When the testing end of the sensor is placed in a liquid (e.g., blood accumulated on a human finger after it is punctured), a portion of the liquid is drawn into the capillary tube by capillary action. The liquid then chemically reacts with the reagent in the sensor, providing an electrical signal indicative of the concentration of the analyte (e.g., glucose) in the measured liquid, which is then fed into an electrical device.

Reactants that may be used to determine the glucose concentration include glucose oxidase. It is contemplated that other reactants may be used to determine the glucose concentration, such as glucose dehydrogenase (dehydrogenase). If the analyte tested is not glucose, it is likely that other reagents will be used.

An example of a test sensor is shown in fig. 1a and 1 b. Fig. 1a and 1b illustrate a test sensor 70 that includes a capillary 72, a cap 74, and a plurality of electrodes 76, 78, and 80. Figure 1b shows the situation without a lid. The plurality of electrodes includes a counter electrode 76, a detection electrode 78, and a working (measurement) electrode 80. As shown in fig. 1b, the test sensor 70 includes a liquid receiving area 82 containing a reactant. It is contemplated that other electrochemical test sensors may be used.

Referring to fig. 2a-b, an example of a meter 100 according to an embodiment of the invention is shown. The meter 100 has an optimal size that may be generally adapted to fit in a user's purse or pocket. Thus, the meter 100 is preferably, although not necessarily, shorter than approximately 2-3 inches in length to improve portability. And preferably, the meter 100 has less than about 6-9 square inches (in)²) The bottom area of (2). The meter 100 may even have about 3 square inches (in)²) The bottom area inside.

As shown in fig. 2a and 2b, the meter 100 includes a display 102 viewable through a front end 120, a test-sensor dispensing portion 104, and a user-interface mechanism 106. The user interface mechanism 106 may be a button, a scroll wheel, or the like. Fig. 2a shows a meter 100 with several display segments. After a user places a liquid (e.g., blood) on the test sensor, meter 100 determines the level of the analyte (e.g., glucose) and displays the reading on display 102.

The meter 100 typically includes a microprocessor or the like for processing and/or storing data generated during the test. For example, user interface mechanisms 106a-b may be depressed to activate the electronics of meter 100, play back and view the results of previous test programs, enter meal and/or athletic metrics, and so forth. The meter 100 may also employ the same or a different microprocessor for power management, including the execution of programs to control the charging functions of the meter 100 with battery-powered devices.

The test-sensor dispensing portion 104 is adapted to receive and/or mount a test sensor and to assist in determining an analyte concentration of a liquid sample. To at least notify the user of the analyte concentration, meter 100 contains a display 102. One example of a display 102 that may be used in the meter 100 is a liquid crystal display. The liquid crystal display typically displays information from the test program and/or is responsive to input signals from the user interface mechanisms 106 a-b. Other types of displays may include, for example, Light Emitting Diodes (LEDs), Organic Light Emitting Diodes (OLEDs), Liquid Crystal Displays (LCDs) with backlights, Thin Film Transistors (TFTs), segmented displays, or other types of transmissive displays. Different types of displays have little or a large effect on the amount of power consumed by the meter.

The meter 100 may be powered by mains power, a battery, or any other suitable power source. The primary power source may contain an AC and/or DC power source operating internally. The meter 100 is preferably battery powered in view of the portability of the meter 100. The battery housing 130 may be located within the back 122 or front end 120 of the meter 100.

In some embodiments, the battery of the meter 100 is charged by a mains power supply, which may be connected to the meter 100 through a power adapter jack 124. Various types of rechargeable batteries may be used to power meter 100, including, for example, lithium-Ion (Li-Ion), lithium-polymer (Li-Po), nickel-cadmium (NiCd), or nickel-metal-hydride (NiMH).

For some meter 100 configurations, a rechargeable battery (not shown) is removed from the battery housing 130 of the meter 100 and placed in a separate charger, for example, plugged into a standard AC wall outlet or connected to a car battery. Other meters may be charged by plugging one end of a dedicated adapter into the power adapter jack 124 of the meter 100 while the battery is still within the battery housing 130. Then, the other end plug of the dedicated adapter is plugged into an AC power outlet, thereby charging the battery. In some embodiments, the meter 100 may be recharged by connecting one end of a dedicated adapter to a power source on the computer, such as a USB interface, while the other end of the dedicated adapter is connected to the power adapter jack 124.

By using a higher charging current than is normally used to charge a battery, the battery charger is able to charge a rechargeable battery quickly, while the battery performance degrades very slowly. This principle of fast charging of the battery is also applicable to battery charger integrated circuits. For example, rechargeable batteries such as Li-Ion, LiPo, NiCd, and NiMH, allow fast charge rates of up to about 2C to 5C without a significant reduction in battery life. The term C is defined as the rated capacity (ratedcapacity) of a given battery being charged. For example, a cell with a capacity of 200mAh has a 1C rate of 200mA, a 2C rate of 400mA, and a 5C rate of 1000 mA. In certain embodiments, charging the battery at a high charge rate with a very short charge time may provide sufficient energy to the meter battery to perform multiple liquid analyte concentration tests.

In certain embodiments, the device may issue an early warning, for example, indicating that the remaining charge of the battery may complete about 10 liquid analyte concentration tests. The device may further issue a final alarm indicating that 2 or fewer tests may be completed, for example, based on the amount of power remaining. In these cases, it is advantageous to charge the battery with a short charging time at a high charging rate, particularly after the last alarm.

For meters similar to the embodiments described herein, the electrical quantities used for a single analyte concentration test are illustrated. Assuming that the test lasts for 2 minutes, during which the display 102 of the meter 100 is continuously active, the meter 100 with a transmissive display (e.g., OLED, LCD with backlight, TFT) may consume up to about 40 milliamps (mA) from a 3.6 volt (V) rechargeable battery. The following mathematical equation shows the energy consumption of the meter as a function of the test duration, cell voltage and current:

E_FROMBATTERY＝I×V_BAT×t_OPERATION

wherein: e_FROMBATTERYFor consuming energy

V_BATIs the voltage of the battery

I is the current consumed by the meter

t_{OPERA TI}Is composed of_ONTime of analyte concentration test

Substituting the values in the above example:

E_{FROM BATTERY}＝40×10^-3A×3.6V×2min×60sec≈17J

for a meter similar to the embodiments described herein, a fast charging scheme for rechargeable batteries is illustrated again. The meter may be connected to the power supply using a dedicated adapter that may be connected to the USB interface or another power supply. In this example, an internal battery charging circuit provides a 2C charge rate. After charging the battery, e.g. for a certain period of time t_CHARGING(e.g., 30 seconds, 1 minute), the energy obtained from the battery charger is roughly the following relationship:

E_CHARGED＝I_CHARGING×V_BAT×t_CHARGING

wherein: e_CHARGEDFor energy derived from battery chargers

V_BATIs the voltage of the battery

For charging current (e.g. for a 200mAh battery, charging at 2C

Electric rate, I_CHARGING＝400mA)

For the duration of charging (e.g. 1 minute in our example)

Substituting the values of the above example:

E_CHARGED＝0.4A×3.6V×60sec＝86.4J

this example shows that, according to the energy consumption example of the single test described above, with 1 test energy consumption equal to 17 Joules (Joules), about 5 tests (86.4J/17J ≈ 5) can be performed with sufficient energy being provided to the rechargeable battery after charging the battery for about 60 seconds at a current rate of 2C.

The use of rapid charging of the meter battery causes the meter to heat up, thereby altering the analyte concentration reading output by the meter. Therefore, for a temperature sensitive instrument, such as an instrument having a rechargeable battery, it is preferable to employ rapid charging, and further, it is preferable to minimize the temperature rise of the device.

The embodiments described herein allow for rapid charging of the battery of a meter (e.g., a portable meter) undergoing temperature sensitive testing, with the battery being rapidly charged by a power source in a short period of time. In some embodiments, after the fast charge is completed, the charge is continued at the normal charge rate. These embodiments desirably minimize the temperature rise of the meter.

In some embodiments, the internal charging circuitry of the meter may have a fast charging mode and a normal charging mode. The internal charging circuit can further limit the temperature rise of the meter by reducing the charge rate by changing the fast charge rate to a normal charge rate with a negligible temperature rise. This embodiment may be particularly advantageous if the user does not unplug the dedicated adapter from the power supply after a quick charge.

In some embodiments, once the meter battery is connected to an external power source, such as a USB interface or power adapter, the internal charging circuit or battery charger may first enter a fast charge mode and then switch to a normal or reduced charge mode depending on the temperature rise condition of the particular portable temperature sensitive meter. For example, the fast charge mode may have a charge rate of about 5C. The charge rate may exceed 5C in other embodiments. The charge rate will vary with such conditions as the configuration of the battery or the output current of the power supply (e.g., USB interface or power adapter). In the case of a lithium ion battery, the maximum charge rate is approximately 2C. In the case of a USB interface, the current capacity may be 100mA or 500 mA.

In some embodiments, when the rapid charging of the rechargeable battery is complete, the internal circuitry may provide a perceptible signal to the user, such as an audible signal or a light signal. This signal will let the user know that the battery has sufficient energy to power the desired test. At this point, the user may choose to unplug the meter power plug and perform an analyte concentration test. If the user does not unplug the meter power plug, the charging circuitry of the meter may switch to a normal charging mode providing a charge rate in the range of, for example, about 0.5C to 1C. The normal charge mode generates less heat from the battery than the fast mode with a higher charge rate. In certain embodiments, the normal charging mode may be set to a charging current level that may equalize heat dissipation due to charging and heat radiation from the temperature sensitive instrument to the surrounding atmosphere (e.g., air). In some embodiments, it may be desirable to maintain the temperature reached during the fast charge mode in the normal charge mode.

Referring now to fig. 3, a schematic diagram of a charging circuit 300 for a rechargeable battery 310 is shown, according to some embodiments. The charging circuit 300 experiences a battery warm-up during charging of the battery 310, similar to that experienced during charging of the meter battery. The battery 310 has an internal Equivalent Series Resistance (ESR)312 that causes the battery to dissipate heat. In addition, the temperature rise in battery 310 will be proportional to the charge time and the second order charge current. ESR varies depending on the type of battery. For example, a 50% discharged lithium polymer battery has a typical equivalent series resistance of about less than 0.07 ohms. The charging circuit 300 also includes a charger 330, such as an external power source, connected to the battery 310.

Another example illustrates the calculation of an approximation of the amount of heat generated by the battery in the fast charge mode. Assuming a lithium ion battery, such as the one discussed above with a 2C current rate and a 200mAh capacity, the charge current value is calculated as follows:

I_CHG＝2×200＝400mA＝0.4A

the amount of heat generated by the internal equivalent series resistance 312 of the battery 310 during power consumption or charging may be calculated using the following relationship:

P＝I_CHG ²×ESR

substituting the above values, the power consumption of the battery is:

P_DISP＝(0.4A)²×0.07＝0.012W

assuming a fast charge of 60 seconds, the energy consumption result is 0.72 joules calculated using the following relationship:

Q＝P_DISP×t＝0.012W×60sec＝0.72J

the general relationship for heat transfer is expressed as:

Q＝m×(ΔT)×C_P(J)

wherein Q is the amount of heat transferred;

Δ T ═ change in temperature;

C_Pspecific heat (specific heat) of the battery; and

mass m

Specific heat (specific heat) will vary depending on the type of rechargeable battery used. In the case of a lithium polymer battery made of a hybrid plastic/metal foil/fiber material, the specific heat is within 1 to 3J/gram ℃. The temperature rise is calculated conservatively, with lower values of specific heat being employed. The typical mass of a 200mAh lithium polymer battery is about 5 grams (grams). Substituting the above numerical values and results, the temperature rise obtained by the heat transfer relational expression is:

for the above example applicable to the rapid charging scenario, a temperature rise of 0.14 ℃ or less is negligible in some embodiments and is expected to not affect the analyte concentration reading. In other embodiments, for analyte concentration testing of a liquid sample, temperature rises of about 1 ℃ or less may be negligible. Furthermore, the above example conservatively estimates the temperature rise to be higher than expected because neither the heat transfer between the meter and air is subtracted from the calculation, nor the temperature rise is calculated based on the entire battery-meter system. On the contrary, the temperature rise is calculated only by making a guard estimate of the battery.

The above calculations are based on a set of operations that employ an assumed 60 second fast charge time and other assumed factors. The calculations show that a shorter fast charge time, for example 30 seconds at a 2C charge rate, provides sufficient energy to assume that the meter is performing more than 1 analyte concentration test.

Referring now to fig. 4 and 5, fig. 4 shows a standard charging algorithm and fig. 5 discloses an embodiment of a fast charging algorithm. The charging sequence of the algorithms of fig. 4 and 5 begins with a pre-charge phase and then enters a current regulation phase, ending with a voltage regulation and end phase, after which the battery is considered charged. The fast charge algorithm of fig. 5 further divides the current regulation phase into two separate steps. The current regulation phase is initially a fast charge mode or a high current regulation phase with a high temperature rise, after reaching a preset time or a preset charge voltage, the charge current will drop or shift to a low current regulation phase with a low temperature rise.

With respect to fig. 4 and 5, the battery may continue to charge as long as the battery is drawing energy from the battery charger until the battery reaches the regulated voltage, at which point the charging current drops until the charge is deemed complete. The difference between fig. 4 and fig. 5 is that in the standard charging algorithm (fig. 4), the charging current remains constant from the moment the minimum charging voltage is reached until the moment the regulated voltage is reached. However, in the rapid charging algorithm, after the minimum charging voltage is reached, the charging current rises for a short period of time, and then the charging voltage drops, so that the temperature rise is reduced to a level that is negligible for any temperature sensitive test performed on the meter. The charging time of the algorithm of fig. 5 may be longer than the standard charging algorithm shown in fig. 4.

Referring now to fig. 6, an embodiment of a finite state machine for rapid charging of a meter battery is shown. The embodiment of fig. 6 may be implemented using, for example, a controller or microprocessor. Step 600 the meter begins in a stand-alone mode or no-charge mode, where the meter is not connected to a power source, e.g., a power adapter or USB interface. The meter is connected to a power source, step 605, which in turn may initiate a charging algorithm in the meter containing the rechargeable battery. In certain embodiments, at step 610, the battery begins charging at a fast charge rate, where the current is adjusted to a charging current of, for example, 2C to 5C. The fast charge rate continues for a preset time period, such as 30 seconds or 1 minute, step 615. The fast charge time may also be determined based on the battery reaching a threshold charge voltage but not exceeding, for example, a certain time or temperature rise.

During the fast charge in step 610, step 625 may evaluate whether the battery temperature is too high by monitoring the temperature sensor. In some embodiments, if step 625 determines that the battery temperature is too high, the charging process may stop and a determination may be made as to whether the charger and/or battery has failed at step 630. At this point, the meter may return to the stand-alone mode of step 600 and may perform corrective action. In certain embodiments, step 635 may notify the user of a quick charge completion with an audible or visual alarm or other signal once the threshold time or voltage is reached at step 620.

The fast charge method of the finite state machine may then proceed to step 640, the normal charge phase where the charge current is reduced. In certain embodiments, the meter may then disconnect power at step 645. Step 650 may also additionally evaluate whether the battery temperature is too high at this time, which may cause the charging process to stop, and step 630 determines whether the charger and/or battery has failed. During the normal charging mode, the process may also determine whether the battery voltage exceeds a threshold at step 655. If the threshold is exceeded, the charge may proceed to step 660, a constant voltage regulation phase. In certain embodiments, the meter may disconnect power at step 665. Step 670 may also be performed to further determine whether the battery temperature is too high at this time, which may cause the charging process to stop, and then step 630 may determine whether the charger and/or the battery have failed. In certain embodiments, the process may periodically detect whether the charging current exceeds a threshold value at step 675. If the charging current exceeds the threshold, the charging routine may continue to run during the constant voltage regulation phase at step 660. If the charging current is below the predetermined threshold, step 680, step 685 notifies the user of the completion of charging the battery or system, such as by an audible or visual prompt. At this point the meter may enter a standby mode at step 690 and the charging process ends. At step 695, the user may then unplug the meter, at which point the meter returns to the stand-alone mode of step 600.

The embodiments disclosed herein for rapidly charging a battery of a temperature sensitive instrument have many advantages. For example, rather than continuously charging the battery at a high constant rate until the voltage reaches a preset level, the battery is charged at a high rate for only a short period of time to provide sufficient energy for a limited number of blood glucose concentration tests. After the fast charge, the charger transitions to a low rate or normal charge mode that maintains the battery temperature at the end of the fast charge phase. The embodiments disclosed herein, such as in the case of a meter, provide a user with the benefits of using a meter that operates on a rechargeable battery, while also allowing the user to quickly charge the meter without a decrease in test accuracy due to temperature rise.

In certain embodiments, the temperature rise of the battery or meter may be monitored periodically. If the temperature rise of the instrument battery exceeds a preset threshold, the rapid charging procedure or the normal charging procedure can be cancelled. Such a temperature rise may suggest that the meter device or the battery is malfunctioning.

In certain embodiments, the battery-powered meter is adapted to determine an analyte concentration of a liquid sample with the aid of a test sensor. The meter contains a test port or opening sized to receive at least a portion of a test sensor. The front end portion has a display that can display the analyte concentration of the liquid sample. The user interaction mechanism is used to control the meter. A housing may be provided for housing a rechargeable battery. The battery charger component is operatively connected to the meter and is also capable of executing a rapid charge algorithm for charging the battery. In one embodiment, the algorithm includes: (i) monitoring connection to an external power source, and (ii) if the external power source is monitored, performing a fast charge procedure to fast charge the battery at a first charge rate until a first predetermined event occurs, and then charging the battery at a second charge rate until a second predetermined event occurs. The second charge rate is lower than the first charge rate. In other embodiments, the temperature rise within the rechargeable battery caused by the first charge rate has a negligible heat transfer effect on the liquid sample.

In other embodiments, the battery-powered meter is a blood glucose meter. The battery powered meter may have a first charge rate in the range of 2C to 5C. The battery powered meter may also have a second charge rate below 1C. The battery charger element may also be part of an integrated circuit.

In other embodiments, the first predetermined event of the battery powered meter is the passage of a predetermined period of time. The preset time may be about one minute or less. The first predetermined event of the battery powered meter may also be the exceeding of a predetermined charging voltage or the exceeding of a threshold temperature of the rechargeable battery. The first preset event of the battery powered meter may also be the exceeding of a threshold temperature of the meter.

In other embodiments, the external power source for the battery powered meter may be a port on the computer device. The rechargeable battery may also be monitored periodically for elevated temperature readings.

In certain embodiments, a method of rapidly charging a battery of a blood glucose meter or other fluid analyzer includes monitoring a connection to an external power source and performing a rapid charging routine that charges the battery at a first charging current rate for a first predetermined period of time. After the first predetermined period, the method further includes performing a normal charging routine to charge the battery at a second charging current rate for a second predetermined period. The first charging current rate is greater than the second charging current rate. The first predetermined period is based at least in part on an estimated charge current induced temperature rise in the battery related to a first charge current rate.

In other embodiments, the first preset period of time of the method is based at least in part on a threshold charging voltage. The meter may also contain a liquid crystal display and the threshold charging voltage may be sufficient to conduct 5 or fewer blood glucose concentration tests. The first charging current rate and the second charging current rate may also be generally constant.

In other embodiments, the method further comprises notifying a user of the blood glucose meter with a perceptible signal after the first preset time period. After a second preset period of time, an end-of-charge procedure may also be performed that charges the battery at a third current rate, which is lower than the second charge current rate, until a preset event occurs. The third charging current rate may also be continuously decreased.

In certain embodiments, a computer readable medium encoded with instructions controls the rapid charging of a battery of a meter (e.g., a blood glucose meter). The meter will typically perform temperature sensitive tests, such as when determining the analyte concentration of a liquid sample. The instructions may include monitoring a connection to an external power source. A fast charge routine or algorithm may then be executed to charge the battery at the first charge current until a first predetermined event occurs, such as the passage of a predetermined period of time or the reaching of a particular threshold voltage. Following the occurrence of the first predetermined event, a normal charging routine or algorithm may be executed to charge the battery at the second charging current until a second predetermined event occurs. The first charging current is greater than the second charging current.

Certain embodiments of battery-powered meters, such as systems for testing blood glucose concentration, may contain a battery fuel gauge. For example, a battery fuel gauge integrated circuit may be incorporated into the system to determine the state of charge of the battery. The battery charge information may also be utilized by a power management program running within the battery powered instrumentation system. By managing power during use and non-use, the power management program can extend the operating time of the meter. For example, by controlling power consumption during periods of analyzing blood glucose concentrations and during intervals between such analyses, a power management program in a battery-powered glucose meter may allow the meter to be used longer without recharging the battery.

As previously described with respect to the exemplary embodiment shown in FIG. 2, various types of rechargeable batteries may be used to power the meter, including lithium-Ion (Li-Ion), lithium-polymer (Li-Po), nickel-cadmium (NiCd), or nickel-metal hydride (NiMH) batteries. The use of a lithium battery may provide certain benefits to the operation of the meter because the voltage of the lithium battery generally does not drop substantially during the use of the meter, i.e., during the discharge process.

Fig. 7 shows a battery discharge curve according to certain embodiments of the present application. The discharge curve indicates the change in load voltage of the Li-Po cell during discharge of the cell in which the meter (e.g., a blood glucose meter) is operating. When fully charged, the Li-Po cell has a voltage of about 4.1 volts (V). The discharge curves are shown for the cells operating at 20%, 50%, 100%, i.e., 0.2C, 0.5C and 1C, respectively, of the rated capacity (C). For example, when a Li-Po battery is operated at 0.5C, the Li-Po battery experiences a voltage variation of about 40mV or less, ranging from 40% of the remaining capacity of the battery to 20% of the remaining capacity. The voltage variation of the Li-Po cell may be in the range of 100mV even with 0.2C to 1C discharge current fluctuations. For an initial discharge current of 0.5C, this may mean that the discharge current drops to 0.2C or rises to 1C, and the voltage varies by + -50 mV. Fig. 7 further illustrates that when the remaining capacity is less than 5%, the load voltage of the Li-Po battery (e.g., a battery usable for a meter) may be significantly decreased.

For certain battery-powered devices, such as portable meters using lithium batteries, it is advantageous to use a battery fuel gauge because conventional direct voltage measurement methods for determining the state of charge of a battery are generally not suitable for Li-Po or Li-Ion batteries. For example, as shown in fig. 7, the voltage of the lithium battery does not change significantly during the discharge phase of the battery. Because the voltage variation of a lithium battery, which may be attributed to a load on the battery of a battery powered device or a battery discharge, is small, there is difficulty in evaluating the remaining capacity. The battery fuel gauge may continuously monitor the current flowing through the battery in both directions, charge and discharge, counting, for example, the number of coulombs the battery receives during charging and the number of coulombs the battery loses during discharging.

FIG. 8 shows a circuit according to some embodiments of the invention including a battery charger 801 with a fuel gauge 803. The battery charger 801 may be adapted for use with a meter, such as a blood glucose meter. The battery charger may be connected to a main power supply 811. The primary power source may be a power outlet, a generator, a wall-mounted AC/DC adapter, a USB interface, or other power source capable of providing sufficient energy to recharge the batteries. The battery charger 801 is connected to the positive pole of the battery 802. The negative terminal of battery 802 is coupled to ground 820 through sense resistor 807. As shown in fig. 8, microcontroller 805 and fuel gauge 803 may be powered by voltage regulator 804. The voltage regulator 804 is configured in relation to the battery charger 801 and the battery 802 such that the voltage regulator always receives energy from the battery charger 801 (e.g., when the system is charging the battery) or the battery 802 (e.g., when the system is discharging). An interface 813 between microcontroller 805 and fuel gauge 803 allows information to be passed between the two devices to determine the state of charge of battery 802. The microcontroller 805 may include a real-time clock and may further receive and process data from the fuel gauge 803. After the microcontroller 805 processes the data from the fuel gauge, the state of charge of the battery 802 may be displayed on the display 806.

The embodiment shown in fig. 8 illustrates the charging process where current flows from the battery charger 801 to the battery 802. During charging, current constantly flows from battery 802 through sense resistor 807 to ground 820. During charging, the fuel gauge 803 monitors the voltage across the sense resistor 807 to determine the number of coulombs the battery 802 receives from the battery charger 801. When the battery 802 is fully charged, the battery charger 801 sends a battery charged signal 812 to the microcontroller 805. The communication between the battery charger 801 and the microcontroller 805 to notify that charging is complete also includes synchronizing the microcontroller 805 with the fuel gauge 803. The microcontroller may communicate with the display 806 in synchronization or near synchronization with the battery charge done signal 812 so that a "charge done" text or icon is displayed on the display 806 indicating that the charge is done.

The battery charger 801 may be disconnected from the main power supply 811. When this occurs, as shown in fig. 8, battery 802 becomes the sole power source for the circuit. Also, when disconnected from the main power supply 811, the direction of current previously flowing from the battery to the detection resistor 807 is changed or reversed. At this time, the fuel gauge 803 also immediately or nearly immediately detects the reverse polarity of the voltage across the sense resistor 807. The reverse polarity of the sense resistor 807 triggers the fuel gauge 803 to begin tracking the output current of the battery 802 by counting the energy units, coulombs, that exit the battery 802 as the battery discharges. As shown in fig. 8, during the circuit discharge phase, microcontroller 805 and fuel gauge 803 may communicate periodically or nearly continuously via interface 813, causing the microcontroller to receive updates regarding the state of charge of battery 802.

The main power supply 811 may be connected to the battery charger 801 at any time during the discharging process. This connection will cause the direction of current flow through the battery 802 to reverse, switching from a discharging mode to a charging mode. At or near the instant that the direction of current flowing through the battery 802 reverses, the fuel gauge 803 tracks the current flowing into the battery 802 by counting the number of coulombs that enter the battery 802 during charging.

The charging and discharging process can be monitored periodically (e.g., periodically, continuously, etc.) by the fuel gauge 803 and the microcontroller 805. By periodic or continuous monitoring, microcontroller 805 has updated information regarding the battery remaining energy units from which a relatively accurate assessment of the state of charge of battery 802 can be made. The battery charge status determined by microcontroller 805 may then be displayed on display 806. This embodiment displays a four-grid icon in the display 806 that includes a status of the power to the user.

Portable or battery powered meters may incorporate features that include a sleep mode or a standby mode that limits power consumption during periods when the meter is not in use or is limited in use. As with the embodiment shown in fig. 8, microcontroller 805 may cause the circuit to enter a sleep mode. To limit power consumption, it is desirable to remove the fuel gauge 803 from the power distribution circuit when the microprocessor 805 puts the system into sleep mode. As shown in fig. 8, a power switch control signal 815 from the microcontroller 805 to a power switch 814 may be used to isolate the electricity meter 803.

The embodiment shown in fig. 8 is advantageous because it allows a significant reduction in power consumption in sleep mode. The electricity meter that continuously monitors the remaining battery power may consume a large amount of electricity. The electricity meter 803 is continuously operated, even a low power consumption electricity meter, and may consume approximately 50 to 100 microamps even if the system enters a sleep mode. Such power consumption may be considered significant in portable battery powered systems such as blood glucose meters. Microcontroller 805 may consume only a few microamps (e.g., about 1 to 10 microamps), even while in sleep mode.

In some embodiments, when the system enters a standby or sleep mode, the battery fuel gauge 803 is isolated and is not allowed to drain battery power. A power switch 814 may be used to control the flow of electrical energy through the voltage regulator 804 to the electricity meter 803 during discharging, i.e., when the main power source 811 is disconnected. A voltage regulator 804 is incorporated into the circuit for supplying power to the microcontroller 805 and the fuel gauge 803 during discharge. The power switch 814 is coupled to the microcontroller 805 so that the microcontroller 805 can send a power switch control signal 815 to the power switch 814. The power switch 814 will then open or close the circuit that supplies power to the electricity meter 803. For example, if the microcontroller 805 determines that the meter should enter a standby or sleep mode, the microcontroller 805 sends a signal 815 to the power switch 814, cutting off the circuit directing current to the fuel gauge 803. As shown in fig. 8, the battery 802 eliminates the current drain of about 50 to 100 microamps by opening the circuit through the power switch 814. When the meter returns to the operating mode, the microcontroller 805 can send another signal 815 to the power switch 814 to complete the circuit between the battery 802 and the electricity meter 803, and current is reintroduced into the electricity meter 803 to allow the electricity meter 803 to be re-operated.

It is desirable that the meter continue to evaluate the remaining usage time of the battery 802 in a standby or sleep mode. For example, in the case of a blood glucose meter, the user may or may not use the device daily, and thus remain in a standby or sleep mode for one, several or one or several weeks. In the embodiment shown in fig. 8, microcontroller 805 still consumes about 2 to 3 microamps of current in sleep mode (e.g., very low power consumption). As shown in fig. 8, in sleep mode, although the electricity meter 803 may be removed from the power consuming circuitry, it is still important to track the power consumption of the remaining power consuming components, such as the microcontroller 805. But removing the fuel gauge 803 from the power consumption circuit, the function of the fuel gauge 803 is subtracted accordingly — as it is a device that tracks current build up and consumption.

In some embodiments, during periods of electricity meter inactivity, the assessment of remaining battery time or power consumption may be accomplished using a processor or microcontroller with a power management program. The power management program may extend the run time of a meter having a limited power source, such as a rechargeable battery.

In the embodiment shown in FIG. 8, the microcontroller 805 executing the power management program may perform several steps before entering the standby mode or sleep mode. The microcontroller 805 includes a timer, or receives data from a timer. The timer holds a reference time for evaluating the remaining capacity of the battery 802. The timer may use a real time clock to determine the reference time. For example, before entering sleep mode, the microcontroller 805 records a reference time or records the actual time of the last state of battery charge. The microcontroller 805 then sends a signal 815 to the power switch 814 to open the circuit to the electricity meter 803, i.e., to remove the electricity meter 803 from the power consumption loop. In the case where the electricity meter 803 is not powered on, the energy consumed from the battery 802 is greatly reduced, but the electricity meter stops tracking power consumption. However, before entering the sleep or standby mode, the reference time is recorded by the microcontroller 805, which allows the power consumption of the instrumentation system to be determined after the microcontroller 805 wakes up. The meter may be user-activated to exit the sleep mode, e.g., the user may press a button or set some predetermined wake-up condition for the meter.

The microcontroller 805, upon receiving a prompt to exit the standby or sleep mode, performs some operations to recalculate and restore the amount of battery discharge during periods when the fuel gauge 803 is not operating. The power switch control signal 815 is sent to the power switch 814 to power the battery fuel gauge 803. Microcontroller 805 also determines the duration of the standby or sleep mode by subtracting the first reference time recorded when microcontroller 805 entered the sleep mode from the second reference time currently exiting the sleep mode, e.g., the time the microcontroller was awake or entered the operating mode. Microcontroller 805 then multiplies the calculated sleep mode duration by the known current and voltage of the sleep mode. The product of the duration of the sleep mode and the voltage and current of the known sleep mode is the power consumption of the circuit in the standby or sleep mode. The microcontroller 805 then subtracts the calculated power consumption from the last recorded known state of battery charge, e.g., the amount of remaining charge just prior to entering the last standby or sleep mode. The result is an estimate of the battery state of charge.

FIG. 9 illustrates a finite state machine of a method for power management of a battery-powered device according to some embodiments of the present application. The power management method may be an algorithm or program executing on a computer or computer system that monitors the power of the battery powered device. For example, the method may be performed in a system containing a processor or microcontroller-type device. The method can reduce the average power consumption of the integrated circuit of the fuel gauge, and simultaneously, the information loss of the accurate state of the battery power can be reduced as much as possible.

In some embodiments, a device, such as a meter (e.g., a battery-powered blood glucose meter), may operate under normal operating conditions. The meter may be set to an operational mode (e.g., normal mode) and a sleep mode (e.g., standby mode). At step 900, the meter is enabled for normal operation, and at step 910, a request to enter sleep mode may be received by the microcontroller, which may occur based on user input or a preset period of time elapsing that triggers generation of a signal that is received by the processor or microcontroller. Upon receiving the request for sleep mode at step 910, the processor or microcontroller may record the time of the request and record the state of battery charge at the time of the request at step 920. In certain embodiments, the status information of the battery charge is from data received by the processor from a battery charge meter (e.g., the meter shown in fig. 8). To reduce the power consumption of the sleep mode, a power switch that controls the electricity meter current may be turned off to cut off the power of the electricity meter. Then, at step 930, the microcontroller or processor may remain in a sleep mode during which power consumption may be limited to only the microcontroller. While in sleep mode at step 930, the microcontroller may loop and wait to receive a signal identifying the wake-up event of step 940. The wake-up event of step 940 may include, for example, receipt of an input from a user of the meter, connection of a primary power source, a pre-selected trigger event, and the like. After the wake-up event of step 940 is received by the microcontroller, the battery state of charge after the sleep mode is determined and the battery state of the fuel gauge is updated at step 950. The update of the battery state of charge may be determined using the duration of the sleep mode and the current and voltage in the circuit during the sleep mode. The wake-up event of step 940 may also include sending a signal to a power switch that energizes the fuel gauge.

Upon exiting the sleep mode, the battery power state may be determined immediately or shortly after the wake-up event at step 940. After the updated state of battery charge is determined, step 960, the meter may then re-enter the normal operating mode, e.g., operational mode, of step 900. During normal operation of the device at step 900, a timer (e.g., a real time clock) may be used at step 970 to record a reference time, such as the time that the circuit is switched between a charging mode, an operational discharge mode circuit, or a sleep discharge mode. During the normal operating mode, step 975 may continuously or periodically update and display the battery state of charge on the display using information received from the fuel gauge. During normal operation of a device, such as a battery-powered blood glucose meter, a primary power source may be connected to a battery charger in the system, step 900. Monitoring of the battery charger may not be completed until a signal is sent to the microcontroller at 980 that the charging is complete. When the battery is charged, another signal may be sent to update the fuel gauge at step 985. After sending a signal to update the battery state of charge of the fuel gauge, the apparatus may return to the normal operation mode of step 900.

In certain embodiments, a portable meter having an electrical circuit is equipped with a battery to power a sensing element in the electrical circuit. The meter includes a processor powered by the circuit. The processor may operate the meter in an operational mode and a sleep mode. The electricity meter is powered by the circuit. The fuel gauge tracks the state of battery charge data received from the battery during an operating mode in which the meter is operating. The interface transmits the status of the battery charge data from the fuel gauge to the processor. The power switch is set by the processor to be turned off or on to control whether or not current flows to the fuel gauge. The processor sends a signal indicating that the power switch is in the off position if the meter enters the sleep mode, and sends a signal indicating that the power switch is in the on position if the meter enters the operational mode. Before entering the sleep mode, the processor records a first state of battery charge and a first reference time immediately before entering the sleep mode. Further, the processor determines a second state of battery charge immediately at a second reference time after the meter has just exited the sleep mode into the operational mode. And determining the second state of the battery electric quantity according to the recorded first state of the electric quantity, the first reference time, the second reference time and the preset energy utilization rate of the meter in the sleep mode period.

In certain embodiments, the portable meter is a blood glucose meter. The fuel gauge may continuously track the state of charge of the battery during the meter's operational mode. The electricity meter may be an integrated circuit. The portable meter may further include a display coupled to the processor for displaying the current battery charge status. The processor may be a microcontroller. The battery may be a rechargeable battery. The portable meter may enter an operational mode when the primary power source is charging the battery.

According to another embodiment, a power management method includes a battery powered meter operating in an operating mode and a standby mode. A battery powered meter includes a battery fuel gauge and a microcontroller. The method includes the step of receiving a first request to enter a standby mode. A first state of battery charge of the meter is recorded immediately at a first reference time immediately after receiving the first request. The first reference time is recorded with a microcontroller. The meter enters a standby mode and the power supply to the battery fuel gauge is also cut off in the standby mode. And receiving a second request at a second reference time, exiting the standby mode and entering the working mode. The second reference time occurs after the first reference time. In response to the second request, a second reference time is immediately recorded, and the microcontroller determines a second state of the battery charge based on the first reference time, the second reference time, a standby mode current of the meter, and a standby mode voltage.

In some embodiments, a first state of battery charge is determined with a battery fuel gauge. The battery powered meter may first be operated in an operational mode. If the meter is in the active mode, the battery charge status can be updated using battery charge data received by the microcontroller from the battery charge meter. The updating may be performed continuously. The state of charge of the battery can be displayed on a display meter.

According to yet another embodiment, a computer-readable storage medium has instructions stored thereon for managing power for a battery-powered meter operating in an operating mode and a sleep mode. The instructions include the steps of receiving a first request to enter a sleep mode, and recording a first state of battery charge of the meter. The recording is performed immediately at a first reference time immediately after the first request is received. A first reference time is recorded. The meter enters a standby mode in which power to the battery fuel gauge is cut off. A second request is received at a second reference time to exit the sleep mode and enter the operational mode. The second reference time occurs after the first reference time. The second reference time is recorded immediately after the second request. A second state of battery charge is determined based on the first reference time, the second reference time, the sleep mode current, and the sleep mode voltage.

In certain embodiments, the meter may perform a plurality of operations, such as a blood glucose concentration test operation and a global positioning system. These multiple operations on the portable meter may require more energy to be drawn from the battery. A larger battery, efficient power management techniques, or a combination of both may be used to meet the power requirements.

Although the present invention has been described in detail with reference to the illustrated embodiments, the description is not intended to limit the scope of the invention as defined by the appended claims. For example, rapid charging systems for batteries may be used in a variety of temperature sensitive applications. The embodiments disclosed herein and the obvious variations thereof are considered to be within the spirit and scope of the claimed invention.

Claims (39)

1. A battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising:

a front end portion having a display for displaying the analyte concentration of the liquid sample;

a user interaction mechanism for controlling the meter;

a housing defining an area for receiving a rechargeable battery and defining a port sized to receive at least a portion of a test sensor;

a temperature sensor disposed within the housing; and

a microprocessor disposed within the housing, the microprocessor for performing a fast charge process associated with the rechargeable battery, the process comprising the steps of:

(i) monitoring a connection to an external power source; and

(ii) in response to receiving identification information of the connection with the external power source, performing a charging process for rapidly charging the battery at a first charging rate until a threshold temperature determined with the temperature sensor is exceeded; subsequently charging the battery at a second charge rate, the second charge rate being lower than the first charge rate,

wherein execution of the charging process results in a negligible temperature rise within the rechargeable battery caused by the first and second charge rates, thereby limiting the temperature effect in determining the concentration of the liquid analyte.

2. The battery-powered meter of claim 1, wherein the housing has a length of less than 8 centimeters.

3. The battery-powered meter of claim 1, wherein the bottom area of the housing is less than 39 square centimeters.

4. The battery-powered meter of claim 1, wherein the bottom area of the housing is less than 58 square centimeters.

5. The battery-powered meter of claim 1, wherein the bottom area of the housing is within 19 square centimeters.

6. The battery-powered meter of claim 1, wherein the negligible temperature rise is a temperature rise within the rechargeable battery of less than one degree celsius.

7. The battery-powered meter of claim 1, wherein the second charge rate is below 1C.

8. The battery-powered meter of claim 1, wherein the second charge rate is in the range of 0.5C to 1C.

9. The battery-powered meter of claim 1, wherein the first charge rate is from 2C to 5C.

10. The battery-powered meter of claim 1, wherein the external power source is a port on a computing device.

11. The battery-powered meter of claim 1, wherein the temperature sensor is part of the rechargeable battery.

12. The battery-powered meter of claim 1, wherein the temperature sensor is part of an integrated circuit associated with the microprocessor.

13. A method of rapidly charging a battery in a meter having a port capable of receiving at least a portion of a test sensor, the meter for determining a liquid analyte concentration of a liquid sample, the method comprising the steps of:

determining a temperature based on temperature data associated with a temperature sensor disposed within the meter;

in response to receiving an input relating to the connection of the meter to an external power source, performing a fast charge process for charging the battery at a first charging current until a threshold temperature value determined in the determining a temperature step is exceeded;

in response to the threshold temperature value being exceeded, performing a normal charging process for charging the battery at a second charging current, the second charging current being lower than the first charging current,

wherein the performing of the rapid charging process and the normal charging process results in a negligible temperature rise within the battery caused by the first charging current and the second charging current, thereby limiting temperature effects in determining liquid analyte concentration.

14. The method of claim 13, further comprising performing an end-of-charge process during the normal charging process in response to a preset event, the end-of-charge process charging the battery at a third charging current until another preset event occurs, the third charging current being lower than the second charging current.

15. The method of claim 14, wherein the third charging current is decreasing.

16. The method of claim 15 wherein the negligible temperature rise is a temperature rise below one degree celsius.

17. The method of claim 16, wherein the second charging current is below 1C.

18. A battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising:

a housing defining an area for receiving a rechargeable battery and defining a port sized to receive at least a portion of a test sensor; from and to

A microprocessor disposed within the housing, the microprocessor for performing a fast charge process associated with the rechargeable battery, the fast charge process comprising the steps of:

(i) monitoring the residual battery capacity of the rechargeable battery, which is less than the preset capacity; and

(ii) performing a charging process to charge the rechargeable battery at a charging rate of 2C to 5C within one minute in response to the rechargeable battery being below the preset charge amount,

wherein the determination of analyte concentration by the meter has an estimated energy consumption, the performance of the charging process providing energy to the rechargeable battery to allow more than one determination of analyte concentration to be completed based on the estimated energy consumption, the charging process further minimizing temperature rise within the rechargeable battery, thereby limiting temperature effects in determining liquid analyte concentration.

19. The battery-powered meter of claim 18, wherein the preset charge is a charge associated with an amount of energy sufficient to complete a determination of two or less analyte concentrations based on the estimated energy consumption.

20. The battery-powered meter of claim 18, wherein the charging process provides energy to the battery to complete the determination of approximately five analyte concentrations based on the estimated energy consumption.

21. A battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising:

a front end portion having a display for displaying the analyte concentration of the liquid sample;

a user interaction mechanism for controlling the meter;

a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and

a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of:

(i) monitoring a connection to an external power source; and

(ii) in response to receiving identification information of the connection with the external power source, performing a charging process for rapidly charging the battery at a first charging rate until a first preset event occurs; subsequently charging the battery at a second charge rate, the second charge rate being lower than the first charge rate,

wherein the performance of the charging process minimizes a temperature rise in the meter configured for a temperature sensitive analyte concentration test such that the temperature rise is negligible for the temperature sensitive analyte concentration test.

22. The battery powered meter of claim 21, wherein the analyte is blood glucose.

23. The battery powered meter of claim 21, wherein the second charge rate is below 1C.

24. The battery powered meter of claim 21, wherein the second charge rate is in the range of 0.5C to 1C.

25. The battery powered meter of claim 21, wherein the first preset event is the passage of a preset period of time.

26. The battery-powered meter of claim 25, wherein the predetermined period of time is one minute or less.

27. The battery powered meter of claim 21, wherein the microprocessor comprises an integrated circuit.

28. The battery powered meter of claim 21, wherein the external power source is a port on a computer device.

29. The battery powered meter of claim 21, wherein the bottom area of the housing is less than 58 square centimeters.

30. The battery powered meter of claim 21, wherein the housing has a length of less than 8 centimeters.

31. The battery powered meter of claim 21, further comprising executing a human perceptible signal after the first preset event.

32. A battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising:

a front end portion having a display for displaying the analyte concentration of the liquid sample;

a user interaction mechanism for controlling the meter;

a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and

a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of:

(i) monitoring a connection to an external power source; and

(ii) in response to receiving identification information of the connection with the external power source, performing a charging process for rapidly charging the battery at a first charging rate until a first preset event occurs; subsequently charging the battery at a second charge rate, the second charge rate being lower than the first charge rate,

wherein the charging process is performed in accordance with a temperature rise condition of the meter in view of the meter being configured for a particular temperature sensitive analyte concentration test.

33. The battery-powered meter of claim 32, wherein the analyte is blood glucose.

34. The battery-powered meter of claim 32, wherein the second charge rate is below 1C and the first preset event is the passage of one minute or less.

35. The battery-powered meter of claim 32, wherein the charging process further comprises: (iii) in response to a second preset event during said charging of said battery at a second charge rate, performing an end-of-charge process of charging said battery at a third charge rate until another preset event occurs, said third charge rate being lower than said second charge rate.

36. The battery-powered meter of claim 35, wherein the third charge rate is decreasing.

37. A battery-powered meter adapted to determine an analyte concentration of a liquid sample, the meter comprising:

a housing defining a volume for receiving a rechargeable battery and further defining a port sized to receive at least a portion of a test sensor; and

a microprocessor disposed within the housing, the microprocessor for performing a charging process associated with the rechargeable battery, the charging process comprising the steps of:

(i) monitoring the residual battery capacity of the rechargeable battery, which is less than the preset capacity; and

(ii) performing a fast charge process to charge the rechargeable battery at a charge rate of 2C to 5C in one minute in response to the rechargeable battery falling below the preset charge amount,

wherein the determination of analyte concentration by the meter has an estimated energy consumption, and wherein the performing of the rapid charging process provides energy to the rechargeable battery to allow completion of the determination of one or more analyte concentrations based on the estimated energy consumption.

38. The battery powered meter of claim 37, wherein the preset amount of power is an amount of power associated with an amount of energy sufficient to complete a determination of two or less analyte concentrations based on the estimated energy consumption.

39. The battery powered meter of claim 37, wherein the charging process provides energy to the battery to complete the determination of approximately five analyte concentrations based on the estimated energy consumption.