HK1231255A1 - Methods of extending the life of battery - Google Patents

Description

Method for prolonging service life of battery

Cross Reference to Related Applications

This application claims the benefit of U.S. provisional application No. 61/962,131 filed on month 1 of 2013 and is a continuation-in-part application of U.S. application No. 13/236,436 filed on 9, 19 of 2011 and the benefit of U.S. provisional application No. 61/403,625 filed on 9, 20 of 2010, the entire disclosures of which are incorporated herein by reference in their entirety.

Background

The present invention relates generally to battery technology, and more particularly to technology for extending the operating life of batteries (such as disposable and rechargeable). Most consumer electronics devices use batteries. Batteries are classified according to primary batteries, secondary batteries, and rechargeable batteries of dry batteries. Many electronic devices are sensitive and require very precise voltages to operate properly. In some cases, if the battery supplying the voltage to the electronic device drops too low, not only may the device provide an unreliable output, but the low voltage may also damage the device. Many manufacturers of electronic devices therefore include circuitry that detects the battery voltage level and opens itself if the voltage level drops below a certain level. As an example, a new unused AA battery provides 1.5V. Over time, as the battery charge is consumed by the device utilizing the battery, the battery voltage begins to drop.

Some electronic devices that use disposable batteries (such as AA batteries) are designed to stop operating when the battery voltage drops by around 10%. This means that when the voltage of the AA battery drops to about 1.4V or 1.35V, the battery is no longer usable by the device and has to be replaced with a new battery. Therefore, the entire voltage range between 0V and 1.35V is wasted, resulting in significant inefficiency. This is similar to the scenario where conventionally only 10% of the soda bottles are consumed and the rest are discarded. This would obviously be very wasteful and inefficient.

Another factor that affects the cost of the battery is that some of the materials used in making the battery are difficult to mine and in some cases are considered rare earth materials. The price of some materials has risen because they are only present in countries like china, and china has started to restrict the export of these materials.

In addition to the negative economic impact of cell inefficiency, there are significant environmental impacts. There are about 30 billion batteries sold each year. Batteries pose a particular environmental risk because they contain toxic materials that can enter our natural resources (such as groundwater). They are also not biodegradable. Many countries and municipalities have laws and local regulations regarding battery recycling. In addition, the carbon footprint associated with manufacturing and distributing batteries is of concern. The processes of mining these materials, placing them into batteries, packaging batteries, and shipping them worldwide consume a lot of energy and produce a lot of greenhouse gases. Therefore, improving the use efficiency of the battery provides significant economic and environmental benefits.

Accordingly, there is a need for techniques to improve the efficiency of batteries (such as disposable batteries and rechargeable batteries).

Brief summary

Embodiments of the present invention provide techniques for significantly increasing battery life. According to one embodiment, a battery sleeve for extending the useful life of one or more batteries includes a positive conductive electrode and an insulating layer extending below the conductive electrode such that the positive conductive electrode is positioned above a positive terminal of the battery when the sleeve is coupled to the battery, wherein the insulating layer electrically isolates the positive conductive electrode from the positive terminal of the battery.

In another embodiment, the battery sleeve further comprises a negative conductive electrode configured such that when the sleeve is coupled to the battery, the negative conductive electrode is in electrical contact with the negative terminal of the battery.

In another embodiment, the battery sleeve further comprises a voltage regulating circuit adapted to receive the positive and negative terminals of the battery and provide an output signal on an output terminal electrically connected to the positive conductive electrode.

In another embodiment, the battery sleeve includes a voltage regulation circuit adapted to receive positive and negative voltages provided by the battery and produce a substantially constant output voltage on the positive conductive electrode of the battery sleeve over the duration of the service life of the battery.

In another embodiment, the voltage regulator is housed in an upper portion of the battery sleeve proximate the positive conductive electrode. In an alternative embodiment, the voltage regulator is housed in a lower portion of the battery sleeve proximate the negative conductive electrode.

In another embodiment, when the battery cartridge is coupled to the battery, the positive conductive electrode of the cartridge serves as the new positive terminal of the battery.

In another embodiment, the battery sleeve is configured such that when the sleeve is coupled to the battery, the positive terminal of the battery is covered by the insulating layer such that the positive terminal is not externally electrically contacted.

In yet another embodiment, the battery sleeve is configured such that when the sleeve is coupled to the battery, the negative terminal of the battery is externally electrically contacted.

According to another embodiment of the invention, a battery sleeve for extending the useful life of one or more batteries includes a positive conductive electrode configured such that when the battery sleeve is coupled to at least one battery, the positive conductive electrode of the sleeve serves as a new positive terminal for the at least one battery.

In one embodiment, the battery sleeve further comprises a voltage regulator adapted to receive a voltage provided by the at least one battery and to produce a substantially constant output voltage for the duration of the service life of the at least one battery.

In another embodiment, the battery sleeve further comprises an insulating layer extending below the conductive electrode, wherein the sleeve is configured such that when the sleeve is coupled to the battery, the positive conductive electrode is positioned above the positive terminal of the battery, wherein the insulating layer insulates the positive conductive electrode from the positive terminal of the battery.

In another embodiment, the battery sleeve further comprises a negative conductive electrode configured such that when the sleeve is coupled to the battery, the negative conductive electrode is in electrical contact with the negative terminal of the battery.

In another aspect, a method for extending battery life is provided. The method includes receiving a battery electrical power output from a battery. The battery electrical power output has a battery output voltage that decreases from a first battery output voltage to a second battery output voltage. The battery electrical power output is used to drive a converter that outputs a converter electrical power having a converter output voltage that is greater than the second battery output voltage. The converter electrical power is output from one or more output terminals configured to interface with one or more input terminals of a battery powered device. The converter may be configured and supported relative to the battery to interface with one or more output terminals of the battery. The converter may be embedded within the battery, and the converter electrical power output is output through terminals of the battery.

In many embodiments of the method, the converter output voltage has a substantially constant magnitude as the battery output voltage decreases from the first battery output voltage to the second battery output voltage. The second battery output voltage may be less than 70% of the first battery output voltage.

The method may include directly outputting the battery electrical power when the voltage produced by the battery exceeds a voltage required by a device powered by the battery. For example, the method may include outputting a battery electrical power output from one or more output terminals configured to interface with one or more input terminals of the battery powered device when the battery output voltage decreases from the first battery output voltage to a voltage equal to or greater than a minimum voltage level required for normal operation of the battery powered device.

To further extend battery life, the method may include outputting a reduced voltage relative to a nominal voltage or a voltage originally generated by the battery. For example, the method may include reducing the converter output voltage during at least a portion of the battery output voltage being reduced from the first battery output voltage to the second battery output voltage. For example, during the portion of the battery output voltage that decreases from the first battery output voltage to the second battery output voltage, the converter output voltage may decrease by less than 10% and the battery output voltage by greater than 30%. As another example, the converter output voltage may be less than the battery output voltage during an initial portion of the battery output voltage decreasing from the first battery output voltage to the second battery output voltage.

In many embodiments of the method, the converter includes a boost converter and a buck converter. The boost converter and the buck converter may be controlled such that the converter outputs a voltage: a) less than the first voltage, b) greater than the second voltage, and c) less than 10% change when the battery output voltage decreases from the first battery output voltage to the second battery output voltage. The second battery output voltage may be less than 70% of the first battery output voltage.

The method may be practiced using any suitable battery and/or combination of suitable batteries. For example, the battery supplying the battery electrical power output may include individual batteries connected in series. As another example, the battery may be a 9 volt battery with standard adjacent output terminals. As yet another example, the battery may have a housing, and the converter may be disposed within the housing.

The method may include preventing polarity reversal. For example, the method may include preventing polarity reversal by preventing mating between the negative terminal of the battery and the positive input voltage terminal of the converter.

In another aspect, a battery sleeve for extending the useful life of one or more batteries is provided. The battery sleeve includes a positive conductive electrode, an insulating layer, and a voltage regulating circuit. The insulating layer extends below the conductive electrode such that when the sleeve is coupled to the one or more batteries, the positive conductive electrode is positioned above a positive terminal of the one or more batteries, wherein the insulating layer electrically isolates the positive conductive electrode from the positive terminal. The voltage regulation circuit is adapted to receive a voltage provided by the one or more batteries and produce an increased output voltage on the positive conductive electrode relative to the provided voltage for at least a portion of the useful life of the one or more batteries. In many embodiments, the voltage provided by one or more batteries decreases from a first battery output voltage to a second battery output voltage over the life of the one or more batteries, the second battery output voltage being less than 70% of the first battery output voltage.

In many embodiments of the battery sleeve, the voltage regulation circuit may output a reduced voltage relative to the nominal voltage or the voltage originally produced by the battery in order to further extend battery life. For example, the voltage regulation circuit may output the voltage provided by the one or more batteries to the positive conductive electrode when the voltage provided by the one or more batteries decreases from the first battery output voltage to a voltage equal to or greater than a minimum voltage level required for normal operation of the battery powered device. As another example, the voltage regulation circuit may generate an output voltage that is greater than the voltage provided by the one or more batteries, the output voltage generated by the voltage regulation circuit decreasing during a portion of the useful life of the one or more batteries. For example, during a portion of the useful life of the one or more batteries where the voltage produced by the regulating circuit decreases, the voltage produced by the voltage regulating circuit may decrease by less than 10%, and the voltage provided by the one or more batteries decreases by greater than 30%. As another example, during an initial portion of the useful life of one or more batteries, the voltage generated by the voltage regulation circuit may be less than the voltage provided by the one or more batteries.

In many embodiments of the battery cartridge, the voltage regulation circuit includes a boost converter and a buck converter. Controlling the boost converter and the buck converter such that a voltage generated by a voltage regulation circuit: a) less than an initial voltage provided by the one or more batteries during a useful life of the one or more batteries, b) greater than a final voltage provided by the one or more batteries at an end of the useful life of the one or more batteries, and c) varies by less than 10% during the useful life of the one or more batteries. The final voltage provided by the one or more batteries may be less than 70% of the initial voltage provided by the one or more batteries.

The battery sleeve may be configured for use with any suitable battery and/or combination of suitable batteries. For example, the one or more batteries may include two or more batteries connected in series. The one or more batteries may include a 9 volt battery having standard adjacent output terminals.

The battery sleeve may be configured to prevent inadvertent polarity reversal due to incorrect coupling of the battery sleeve with one or more batteries. For example, the battery sleeve may include a u-shaped member configured to receive a positive terminal of the one or more batteries when the battery sleeve is coupled with the one or more batteries and to inhibit an electrical connection between the voltage regulation circuit and a negative terminal of the one or more batteries so as to prevent a polarity reversal of a voltage provided by the one or more batteries to the voltage regulation circuit.

In another aspect, a battery assembly having an extended service life is provided. The battery assembly includes a housing, one or more voltage generating cells disposed within the housing and providing an output voltage, a positive voltage terminal, a negative voltage terminal, and a voltage regulating circuit disposed within the housing. The voltage regulation circuit receives the output voltage provided by the one or more voltage generating units and generates an increased output voltage relative to the voltage provided by the one or more voltage generating units over at least a portion of its useful life. A voltage regulation circuit is operatively connected to the positive voltage terminal and the negative voltage terminal to output the generated increased output voltage through the positive voltage terminal and the negative voltage terminal.

In another embodiment, the voltage regulation circuit is incorporated within a battery powered device. The voltage regulation circuit is configured to extend the life of one or more batteries used to power the battery powered device by outputting a voltage equal to or exceeding a minimum voltage required for normal operation of the battery powered device, even when the one or more batteries output a voltage less than the minimum voltage required for normal operation of the battery powered device.

Brief Description of Drawings

Fig. 1 illustrates a battery conditioning system 110 according to one embodiment;

fig. 2 shows a simplified diagram of a battery sleeve according to an embodiment;

fig. 3 shows a side view of a battery sleeve coupled to a battery according to one embodiment;

FIG. 4 shows a simplified diagram of a battery cartridge with a conditioning circuit placed along a bottom portion of the cartridge according to one embodiment;

FIG. 5 is a simplified diagram illustrating one embodiment in which a battery sleeve is adapted to be coupled to two batteries connected in series;

fig. 6A and 6B illustrate yet another embodiment in which the regulator and sleeve are adapted such that the sleeve provides the positive terminal of the battery to an external device along with the regulated output voltage; and

fig. 7 shows practical measurements illustrating the advantages of various embodiments.

Fig. 8A shows an inverted exploded view of a battery cartridge having a conditioning circuit positioned to interface with the positive terminal of a battery, according to one embodiment.

Fig. 8B shows a battery and associated insertion path of the battery for coupling the battery with the battery sleeve of fig. 8A.

Fig. 8C shows the battery of fig. 8B coupled with the battery sleeve of fig. 8A.

Fig. 8D, 8E, and 8F illustrate a battery sleeve configuration configured to prevent polarity reversal according to one embodiment.

Fig. 9A and 9B illustrate a regulator assembly configured for use with a nine volt battery according to one embodiment.

Fig. 10A and 10B illustrate a battery including a conditioning circuit disposed within a housing of the battery, according to one embodiment.

FIG. 11 illustrates a two-stage voltage regulation method with a bypass stage, according to one embodiment.

FIG. 12 illustrates a voltage regulation method that utilizes voltage ramping up and down relative to the battery output voltage, according to one embodiment.

Fig. 13 illustrates a three-stage voltage regulation method including a voltage change stage, according to one embodiment.

Fig. 14 is a simplified diagram illustrating a voltage regulation circuit including a boost converter, a bypass circuit, and a filter circuit, according to one embodiment.

Fig. 15 is a simplified diagram illustrating a buck converter circuit, according to one embodiment.

Fig. 16 is a simplified diagram illustrating a voltage regulation circuit including a boost converter, a buck converter, a filter, and a bypass circuit, according to one embodiment.

FIG. 17 is a circuit diagram illustrating a voltage regulation circuit for providing a boost and native bypass voltage, according to one embodiment.

Fig. 18 is a diagram illustrating an electronic device incorporating a voltage regulation circuit, according to one embodiment.

Detailed Description

In the following description of the present embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the embodiments may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that process, electrical or mechanical changes may be made without departing from the scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense.

Fig. 1 illustrates a battery conditioning system 110 according to one embodiment. A positive terminal 104 of the battery 103 is connected to an input terminal 101 of a voltage regulator 105. The ground terminal 100 of the battery 103 is connected to the ground input terminal 106 of the voltage regulator 105. In one embodiment, the negative terminal 100 of the battery needs to be routed to where the voltage regulator 105 is physically located. This may be achieved by a flexible PCB forming part of the battery sleeve as described in more detail further below. An output terminal 102 of the voltage regulator 105 provides an output of the battery regulation system 110. There is an insulator placed between the positive terminal 104 of the battery 103 and the output 102 of the voltage regulator 105.

The operation of the battery regulation system 110 is described next. In an exemplary embodiment of the system 110, the output 102 of the system 110 is regulated to 1.5V. The new AA battery provides a voltage in the range of 1.5V to 1.6V to the regulator 105. The output 102 of the regulator 105 is then regulated to 1.5V, and thus the output of the battery regulation system 110 is fixed to 1.5V. In operation, as the device using the battery conditioning system 110 consumes current from the battery 103, the battery gradually loses the charge initially placed in the battery by the chemical energy storage device. This causes the voltage output by the battery 103 to drop over time. However, the regulator 105 remains providing a constant 1.5V at the output terminal 102 even if the input voltage of the regulator is reduced below 1.5V. This in effect provides a constant voltage to the device using the battery regulation system 110 until the voltage provided by the battery 103 is reduced to the minimum value with which the voltage regulator 105 can operate. In this example, the voltage will be around 0.7V to 0.8V. This allows the terminal device to utilize the battery 103 for a longer period of time. Also, more stored charge in the battery is used before the battery is discarded.

Fig. 2 shows a simplified diagram of a battery sleeve 200 according to one invention. The sleeve 200 covers the top terminal 104 of the battery when coupled to the battery 103. The sleeve 200 has an upper portion that fits snugly around the upper portion of the battery 103. The sleeve 200 is generally designed to ensure a minimal increase in the overall size of the battery when coupled to the battery. The sleeve 200 contains an insulator (not shown) that electrically isolates the positive terminal 104 of the battery 103 from the new positive terminal 204 of the battery sleeve 200. The sleeve 200 further comprises a bottom section comprising a bottom conductor 205, said bottom conductor 205 being electrically connected to the negative terminal 100 of the battery 103. One or more conductive traces 202 route the bottom conductor 205 to conditioning circuitry (not shown) housed in the upper portion of the sleeve 200.

Fig. 3 shows a side view of a sleeve 300 coupled to a battery 103 according to one embodiment. The sleeve 300 wraps around the top portion of the battery 103 and has a top conductor electrode 304 insulated from the positive terminal 104 of the battery 103 by an insulator 312. In this embodiment, the regulator 105 is housed in an upper portion of the sleeve 300. An electrically conductive trace 306 extending in the sleeve 300 connects the input terminal 101 of the regulator 105 to the positive terminal 104 of the battery 103. Another conductive trace 310 extending in the sleeve 300 connects the negative terminal 100 of the battery 103 to the input terminal 106 of the regulator 105. And a third conductive trace extending in the sleeve 300 connects the output terminal 102 of the regulator 105 to the top conductor electrode 304 of the sleeve. The conductive traces 306, 308, and 310 are insulated from each other. As previously described, in operation, the top conductive electrode 304 serves as the "new" positive terminal of the battery.

In an alternative embodiment shown in fig. 4, when battery 103 is inserted into sleeve 400, regulator 405 is placed in the bottom portion of sleeve 400 proximate to where negative terminal 100 of battery 103 will be located. In this embodiment, the positive terminal 104 of the battery 103 is routed by the conductive trace 412 extending through the sleeve 400 to the bottom of the sleeve where the regulator 405 resides. The conductive trace 412 routed to the bottom is connected to the input terminal 101 of the regulator 405, and the other input 106 of the regulator 405 receives the negative terminal 100 of the battery 103 present at the bottom of the sleeve 400. The output terminal 102 of the voltage regulator 405 is then routed up through the conductive trace 414 and connected to the top conductor electrode 404 of the sleeve 400. As in the previous embodiment, the top conductor electrode 404 of the sleeve is insulated from the positive terminal 104 of the battery 103 by an insulating layer 410. In this embodiment, two conductive traces 412, 414 extend between the upper and lower portions of the sleeve 400.

Fig. 5 is a simplified diagram illustrating one embodiment in which a sleeve 500 is adapted to couple to two series-connected batteries 103A, 103B. In this exemplary embodiment, the batteries 103A, 103B are AA batteries that provide a 3V output. The regulator 505 is shown in fig. 5 as being external to the sleeve 500 to minimize clutter. In practice, the regulator 505 is housed in the sleeve 500. The regulator 505 is used in a similar manner to the above-described embodiment. As in the previous embodiment, when the voltage of both batteries drops due to use, regulator 505 provides a constant regulated voltage equal to double the voltage of the new battery.

Fig. 6A and 6B illustrate yet another embodiment in which the regulator and sleeve are adapted such that the sleeve provides the positive terminal of the battery to an external device along with the regulated output voltage. Fig. 6A shows how the positive terminal 104 and the negative terminal 100 of the battery 103 are interconnected with a voltage regulator 605. For clarity, the adjuster is shown separate from the sleeve, although in practice the adjuster will be housed in the sleeve. Fig. 6A also depicts an insulator 610, which insulator 610 insulates the bottom electrode 612 of the sleeve from the negative terminal 100 of the battery 103. Figure 6B more accurately reflects the physical position of the regulator 605 along the bottom of the sleeve. In this embodiment, the output 102 of the voltage regulator 605 is used as the series voltage of the voltage to the battery. Initially, when the battery is new, the output 102 of the voltage regulator 605 is set to 0V or even negative to ensure that the voltage provided by the sleeve to the external device remains 1.5V. As the battery charge drops over time, the voltage regulator 605 maintains a voltage at its output 102 that is substantially equal to 1.5V-V (battery). In other words, the regulator monitors the voltage provided by the battery 103 and if the voltage drops below the regulated voltage, the regulator then generates a voltage to compensate for the drop in battery voltage. As an example, when a battery is used and its voltage drops to 1.1V, the voltage regulator 605 provides a voltage of 0.4V at its output 102.

According to an embodiment of the present invention, the battery sleeve isolates the positive terminal of the battery from an external device when coupled to the battery, and during operation, regulates the battery voltage to a constant voltage and provides the regulated constant voltage to the external device instead of the initial battery voltage. An advantage of such a battery sleeve is that the external device continues to receive a constant voltage and thus continues to operate and draw charge from the battery even after the output voltage of the battery drops below the allowable operating voltage of the external device. It will continue to do so until such time as the output voltage of the battery falls below the range in which the voltage regulation system is operable. In the AA battery example, without the battery sleeve, the battery needs to be discarded when it drops from 1.5V to 1.4V or 1.35V. However, with the sleeve, the battery voltage can drop as low as 0.8V or 0.7V while the external device continues to experience 1.5V. It should be noted that the current level of the battery sleeve needs to be consistent with the current requirements of the end system.

Significant benefits can be seen if the potential benefits of such devices in terms of battery life are observed. For example, the AA batteries in the above examples will use approximately the equivalent charge of the battery output in the range of 1.5V to 1.4V. This means that the life of the battery is over after a drop of 0.1V. If the battery can be used until its voltage reaches 0.8V, the life of the battery ends after a drop of 0.7V. If it is assumed that time is a linear function of voltage drop, the life of the battery can be increased by a factor of 7 in this example. Advantageously, however, time is not completely linear with voltage drop. The time it takes for the battery voltage to drop 0.1V is longer at lower voltages than at higher voltages. This means that if a constant current is drawn from the battery, it will take a much longer time for the battery to discharge from 1.2V to 1.1V than from 1.5V to 1.4V. This means that the degree of increase in battery life can be even more than 7 times that in the above example.

It should be noted that the conditioning circuit has some efficiency that cuts down on the extent of extending battery life, however the life time reduction is quite small. During operation, the regulator itself uses a certain amount of current from the battery. Many available DC-to-DC converters have high efficiencies of around 95%. That is, 5% of the power supplied by the battery is used by the converter and the remaining power is available to the end user. However, the 5% efficiency loss due to the use of the converter is negligible when compared to a gain of 700% of the cell efficiency. It should also be noted that when a drop in battery voltage occurs due to use, the converter efficiency may drop. For example, when the battery voltage drops from 1.5V to 1V, the efficiency of the converter may drop to 50% to 60%. However, because their voltage has dropped below the operable voltage range (i.e., 1.4-1.5V), 50% efficiency remains a significant improvement over current methods of discarding batteries.

The economics of the present invention are attractive. While there may be some cost associated with implementing the present invention, this cost is more than offset by the cost savings achieved by extending battery life to be equivalent to 5 to 7 batteries. The implementation may be external to the battery as described in the various embodiments above, or alternatively the battery manufacturer may incorporate the conditioning circuitry and associated connections inside the battery housing during the manufacturing process. However, the attachable sleeve implementation has additional advantages: it can be used repeatedly. That is, once the battery inside the sleeve is completely depleted, the depleted battery may be discarded and another battery may be placed inside the sleeve. Thus, the cost of the sleeve is spread among many cells, thus minimizing the additional cost per cell. The attachable sleeve (on the implementation of incorporating the regulator inside the battery) has the additional benefit of: no changes to existing battery manufacturing processes, equipment and factories are required.

It should be noted that most, if not all, battery compartments of electronic devices need not be modified to receive a battery cartridge. Although the sleeve slightly increases the height of the battery, the spring used in the battery compartment to hold the battery in place can accommodate the additional height. The length of the spring is typically in the range of 5mm to 10 mm. The increase in height of the cell due to the sleeve is about 1 mm. When inserting the battery with the sleeve into the battery compartment, the extra height is easily accommodated by the spring compressing by a further millimeter. Of course, as technology advances, the thickness of the sleeve may be reduced. For batteries in which both the positive and negative terminals are located along the same end of the battery (such as 9V batteries), the sleeve will have even less of an effect on the size of the battery. This is because for such batteries, the sleeve is simply a male-female converter with an insulator that isolates the positive terminal of the battery from the output of the voltage regulator.

In another embodiment, multiple batteries may be placed in series and one sleeve may encompass a series of batteries, such as the battery shown in fig. 5. As described in the embodiment of fig. 5, the output voltage of the series-connected batteries will be used as an input to the voltage regulator, and the constant output voltage provided by the regulator is provided to the external device. It should be noted that the lifetime of such series-connected cells is increased, even more than in the case of a single cell, as explained next. A single AA battery would be thrown away when its voltage dropped from 1.5V to 1.35V when used without a sleeve. When used with the sleeve, the battery can be used down to 0.8V. If the battery discharge time is linearly related to the discharge rate of the battery, the life extension time will be 0.7V/0.15V or more than 4 times. In contrast, in the case of two AA batteries connected in series and without the use of a sleeve, the two batteries would need to be thrown away when the voltage of the series connected batteries drops from 3V to 2.7V. When used with a sleeve, the series connected batteries can be used to drop from 3V to 0.8V. The life extension time will then be proportional to (3-0.8)/(3-2.7) ═ 2.2/0.3, which results in a battery life extension of over 7 times. This assumes a linear relationship between output voltage and time. However, as described above, the cell behaves non-linearly, since the time taken to drop 0.1V from 1.5V to 1.4V is much shorter than the time taken to drop 0.1V from 1.3V to 1.2V. This advantageously further increases battery life when the sleeve is used.

In yet another embodiment, the device of the present invention is used in conjunction with a rechargeable battery. In the case of rechargeable batteries there is a phenomenon known as the shadow effect. If the battery discharges a small amount of electricity and then is fully charged, and if this process is repeated numerous times, the battery loses its ability to hold a charge. The present embodiment enables the rechargeable battery to operate for longer periods of time and thus reduces the need for frequent recharging by the end user.

Another known phenomenon is: if a rechargeable battery is allowed to discharge beyond a certain limit, the number of times it can be charged is significantly reduced. The present embodiment includes a voltage detection system that detects when the battery reaches a lower limit and cuts off the output voltage, thus increasing the number of times the battery can be charged.

In one embodiment, a technique of printing silicon on metal may be used to implement the sleeve, the conditioning circuitry and its associated connections. There are new techniques for processing circuits using materials other than silicon. These types of printed silicon, in some cases printed onto stainless steel, can be used to shape the sleeve around the cell. This will also allow for better thermal characteristics.

In yet another embodiment, a flexible PCB may be used to route terminals from one side of the battery to the other. These flexible thin layers will allow the sleeve to be very thin.

In yet another embodiment, the efficiency of the regulation system may be adjusted such that, while the system will allow the maximum current output capability of the regulation system to be quite high, the efficiency will be maximized at the output current levels at which the end system is normally operating. For example, if the battery is used in a remote control system, where the average current consumption of the remote control system is 50mA, the voltage boost system, which may be a DC-to-DC conversion system, is set to be as efficient as possible at the output current level.

Fig. 7 shows measurements illustrating the advantages of various embodiments. Three popular AA battery brands (Panasonic, Duracell and Sony) were selected for measurement. An active load circuit drawing a fixed 50mA current is placed at the output of these cells and the voltage of each cell is measured over time. The horizontal axis shows time and the vertical axis shows the battery voltage. The starting voltage of these new batteries was 1.6V. The amount of time it takes for the battery to reach 1.39V is listed (many electronic devices stop operating at 1.39V). The Panasonic cell takes 6.3 hours to reach the level, while the Sony cell takes 4.5 hours. According to an embodiment of the invention, the Panasonic cell, when used in conjunction with a regulator, takes 27.9 hours before it stops providing 1.5V, and the Sony cell, when used with a regulator, takes 32 hours before it stops providing 1.5V. Thus, with the regulator, it takes 4.5 to 7 times longer before the battery needs to be replaced. Thus, the total number of batteries that need to be manufactured and therefore discarded will be reduced by a factor of 4 to 7. This would have a significant impact on our planet if one considers the carbon footprint for extracting all battery materials, their manufacture, their transportation to the store, their packaging, and eventually all toxic materials that we are burying in.

Fig. 8A shows an inverted exploded view of a battery sleeve assembly 700 according to one embodiment, the battery sleeve assembly 700 including a conditioning circuit 705 and a battery sleeve 710 positioned to interface with the positive terminal of a battery. The adjustment circuit 705 may be formed on a suitable substrate (e.g., organic-based, ceramic-based, Flexible Printed Circuit (FPC), rigid-flexible printed circuit (RFPC). the adjustment circuit 705 may be configured according to any suitable adjustment circuit described herein and provide a corresponding adjustment.A sleeve 710 supports the substrate and may be configured to fit over any suitable standard battery (e.g., AA, AAA, C, D), as shown in FIGS. 8B and 8℃ the sleeve 710 may be made of a conductive material coated with a non-conductive material except where the sleeve 710 is electrically connected to the adjustment circuit 705 and where the sleeve 710 contacts the negative terminal of the battery A bottom portion 714 and a top portion 716. The side portions 712 have cylindrical inner and outer surfaces separated by a thickness (e.g., less than 1mm) selected to provide sufficient strength and rigidity while being sufficiently thin to enable the combination of the battery sleeve assembly 700 and a battery to be mounted within a battery operated device configured to receive the battery.

The top of the regulating circuit 705 has spring contacts 718. The spring contacts 718 are configured to extend the overall length of the battery and also flex to become completely flat when two batteries are physically connected in series. The configuration of the spring contacts 718 enables the combination battery and battery sleeve assembly 700 to fit within a battery powered device configured to receive a battery, even when the battery sleeve assembly 700 is externally attached. Fig. 8C shows the combination of batteries installed into battery sleeve assembly 700.

Fig. 8D, 8E, and 8F illustrate a battery sleeve configuration configured to prevent polarity reversal according to one embodiment. Fig. 8D illustrates the battery cartridge assembly 700 with the enclosing member 719 configured to prevent inadvertent polarity reversal. The encapsulation member 719 has a u-shaped configuration shaped to receive the battery positive terminal from mating with the positive input contact on the substrate 705, while preventing the battery negative terminal from mating with the positive input contact on the substrate 705. Fig. 8E shows a close-up view of the substrate 705 and the encapsulation elements 719. Fig. 8F shows a close-up exploded view of the substrate 705 and the encapsulation elements 719. The encapsulation member 719 may be formed of a suitable non-conductive encapsulation material and may further serve to protect battery sleeve components (such as conditioning circuit components) located on the substrate 705 from damage caused by contact.

Fig. 9A shows a regulator assembly 720 configured for use with a nine volt battery 721 according to one embodiment. The regulator assembly 720 includes a female input voltage connector 722 configured to couple with a male positive terminal 723 of a battery 721; a male input voltage connector 724 configured to couple with a female negative terminal 725 of a battery 721; a substrate assembly 726; a convex positive voltage output terminal 727; and a concave negative voltage output terminal 728. The substrate assembly 726 includes conditioning circuitry 729. The regulating circuit 729 is electrically connected to the female input voltage connector 722 and the male input voltage connector 724 to receive the output voltage and current from the battery 721. The regulation circuit 729 outputs the regulated voltage to the output terminals 727, 728 using any suitable method, such as described herein.

Fig. 9B shows another regulator assembly 730 configured for use with a nine volt battery 721 according to one embodiment. The regulator assembly 730 is similar to the regulator assembly 720 described above, but includes a lower plate 731 and an upper plate 732. Lower plate 731 supports input voltage connectors 722, 724. The upper base plate 732 supports the output terminals 727, 728. The conditioning circuit 729 is sandwiched between the lower plate 731 and the upper plate 732, and is thus protected from accidental contact damage.

Fig. 10A and 10B illustrate a battery 740 including a conditioning circuit 742 disposed within a housing of the battery 740, according to one embodiment. The conditioning circuit 742 may be configured similarly to other conditioning circuits described herein. The regulating circuit 742 may be embedded within the battery using any suitable method to isolate the regulating circuit 742 from the substance within the battery. For example, conditioning circuit 742 may be embedded within a potting material, such as a suitable resin, silicone, ultraviolet light curable acrylic potting compound, polyester, hot melt material, and the like. The conditioning circuit 742 may also be embedded by a suitable casting process, by encapsulation or dip coating, and by encapsulation through conformal coating of a Printed Circuit Board (PCB).

Fig. 11 illustrates a two-stage conditioning method 750 with a bypass stage 752 and a boost stage 754, according to one embodiment. In the bypass stage 752, the battery output voltage 756 is greater than or equal to a selected voltage level 757 (e.g., 1.5 volts as shown). Any suitable voltage (e.g., 1.55 volts, 1.50 volts, 1.45 volts, etc.) may be used as the selected voltage level 757. In many instances, a fully charged battery will output a voltage that exceeds its nominal voltage rating. In the example shown, the battery output voltage 756 is 1.60 volts at time zero, and drops over time to 1.50 volts when used for about 5 minutes, and further drops to 0.80 volts when used for about 46 minutes. When the battery output voltage 756 is greater than or equal to the selected voltage level 757, the regulation circuit directly outputs the battery output voltage 756 through a suitable bypass circuit as described herein. After the battery output voltage 756 drops below the selected voltage level 757, the battery output voltage 756 is used to drive a regulation circuit that outputs the selected voltage level 757 during the boost phase 754. By utilizing the bypass stage 752, the power loss associated with boosting the battery output voltage is avoided during the bypass stage 752 when the battery output voltage is equal to or greater than the selected voltage level 757.

Fig. 12 illustrates a regulation method 760 that utilizes voltage rise and fall relative to the battery output voltage, according to one embodiment. In the illustrated example, the battery output voltage 762 decreases over time during exemplary use from 1.60 volts at time zero to a selected voltage level 764 (e.g., 1.40 volts in the illustrated example) when used for about 12 minutes, and to 0.80 volts when used for about 48 minutes. During a first phase 766, the selected voltage 764 output by the conditioning circuit to the battery powered device is reduced relative to the battery output voltage 762 used to drive the conditioning circuit. For example, the regulation circuit may include a buck converter circuit as described herein to output a reduced output voltage relative to the battery output voltage 762 during the first stage 766. During the second stage 768, the selected voltage 764 output by the regulating circuit to the battery powered device is increased relative to the battery output voltage 762 used to drive the regulating circuit. For example, the conditioning circuit may also include a boost converter circuit as described herein to output an increased output voltage relative to the battery output voltage 762 during the second stage 768.

Fig. 13 illustrates a three-stage adjustment method 770, which includes a bypass stage 772, a voltage change stage 774, and a constant voltage stage 776. During the bypass phase 772, the battery output voltage 778 is output by the conditioning circuit directly to the battery powered device as described herein. The bypass phase is used in the event that the battery output voltage 778 exceeds a first selected voltage level (e.g., 1.45 volts in the illustrated example). Any suitable voltage level may be used as the first selected voltage level. When the battery output voltage 778 is below a first selected voltage level and above a second selected voltage level (e.g., 1.00 volts in the illustrated example), the battery output voltage 778 is used to drive a regulating circuit that is controlled to output a varying output voltage 780. In the illustrated example, the varying output voltage 780 drops from 1.50 volts (when the battery output voltage 778 is 1.45 volts) to 1.35 volts (when the battery output voltage 778 is 1.0 volts). During the constant voltage phase 776, the battery output voltage 778 is used to drive a regulation circuit that is controlled to output a constant output voltage 782 (e.g., 1.35 volts in the example shown). By reducing the amount of voltage boost supplied by the regulation circuit, the efficiency of the regulation circuit is increased, resulting in increased effective battery life.

Fig. 14 is a simplified diagram illustrating a voltage regulation circuit 800, the voltage regulation circuit 800 including a boost converter 802, a bypass circuit 804, and a filter circuit 806, according to one embodiment. The voltage regulation circuit 800 may be used to provide the functionality described herein with respect to extending battery life. The boost converter 802 receives the output from the battery 808 and outputs a regulated voltage to the filter circuit 806, which filter circuit 806 then delivers a smoothed voltage output to the battery powered device 810. The filter circuit 806 may include any suitable combination of one or more inductors and/or capacitors to smooth voltage variations in the voltage output by the boost converter 802.

The boost converter 802 includes an inductor 812, a diode 814, a capacitor 816, a controlled switch 818 (e.g., a MOSFET), and a switch controller 820. The switch controller 820 adjusts the resulting ratio between the voltage output by the boost converter 802 and the voltage supplied by the battery 808 by controlling the opening and closing of the switch 818. When switch 818 is closed, the current through inductor 812 increases. When the switch 818 is open, the inductor 812 drives a reduced amount of current through the diode 814, which causes the capacitor 816 to charge up, which raises the voltage supplied to the filter circuit 806, and thus to the battery powered device 810, relative to the voltage output by the battery 808. Diode 814 serves to prevent discharge of capacitor 816 by the backflow of current through switch 181 when switch 818 is closed. By cycling the switch 818 between open and closed at a rate selected to provide a desired level of charge to the capacitor 816, a controlled increase in the voltage supplied to the battery powered device 810 relative to the voltage output by the battery 808 is produced.

A switch controller 820 controls the opening and closing of the switch 818 by a control conductor 822 connected to the switch 818. The switch controller 820 controls the switch 818 based on the voltage inputs 824, 824 from the battery 808 and the voltage inputs 828, 830 from the voltage output by the voltage regulating circuit 800 to the battery powered device 810. For example, the switch controller 820 may include any suitable control electronics (e.g., microprocessor, microcontroller, etc.) that employs a suitable method for varying the off-on duty cycle of the switch 818 (e.g., via a look-up table) to output a desired voltage level to the battery powered device 810 as described herein for varying the voltage output by the battery 808 during the life of the battery.

Bypass circuit 804 includes a bypass switch 832, the bypass switch 832 being controlled by switch controller 820 via control conductor 834. By closing the bypass switch 832 and opening the boost converter 818, the battery output voltage may be supplied directly to the battery powered device 810 according to the bypass phase described herein.

Fig. 15 is a simplified diagram illustrating a buck converter circuit 850, according to one embodiment. The buck converter circuit 850 is operable to reduce the voltage supplied from the battery 808 to the battery powered device 810, for example, during a first stage 766 described with reference to the voltage regulation method shown in fig. 12, in order to extend battery life.

The buck converter circuit 850 includes an inductor 852, a capacitor 854, a diode 856, a controlled switch 858, and a switch controller 860. The switch controller 860 controls the opening and closing of the switch 858 via a control lead 862. When the switch is closed, current flows through the inductor 852 at an increased rate. If the switch remains in the closed position, the voltage supplied to the battery powered device 810 increases to reach the voltage output by the battery 808. When the switch 858 is open, the voltage supplied to the battery powered device 810 is provided by the discharge of the capacitor 854. If the switch remains in the open position, the voltage supplied to the battery powered device 810 will decrease to zero over time. By cycling the switch 858 between open and closed at a rate selected to provide a desired level of charge to the capacitor 854, a desired reduction in the voltage supplied to the battery powered device 810 relative to the voltage output by the battery 808 is produced.

The switch controller 860 controls the opening and closing of the switch 858 via a control lead 862 connected to the switch 858. The switch controller 860 controls the switch 858 according to the voltage inputs 864, 866 from the battery 808 and the voltage inputs 868, 870 from the voltage output by the voltage regulating circuit 850 to the battery powered device 810. For example, the switch controller 860 may include any suitable control electronics (e.g., microprocessor, microcontroller, etc.) that employs a suitable method for varying the off-on duty cycle of the switch 858 (e.g., via a look-up table) to output a desired voltage level to the battery powered device 810 as described herein for varying the voltage output by the battery 808 during the life of the battery.

Fig. 16 is a simplified diagram illustrating a voltage regulation circuit 900 according to one embodiment, the voltage regulation circuit 900 including a boost converter 902, a buck converter circuit 904, a filter 906, and a bypass circuit 908. The boost converter 902 receives the voltage output by the battery 808 and outputs a regulated voltage to the buck converter 904. The boost converter 902 is configured to controllably increase the voltage output from the boost converter relative to the voltage supplied by the battery 808. In the illustrated embodiment, the buck converter 904 receives the voltage output by the boost converter 902 and outputs a regulated voltage to the filter 906. Alternatively, the position of the converters 902, 904 may be reversed, with the buck converter 904 receiving the voltage from the battery 808 and outputting a regulated voltage to the boost converter 902. The filter 906 is configured to smooth the regulated voltage supplied to the filter and output the smoothed regulated voltage to the battery powered device 810. Any suitable configuration of boost converter 902 may be employed, such as boost converter 802 described herein. Any suitable configuration of buck converter 904 may be employed, such as buck converter 850 described herein. The bypass circuit 908 is configured and functions similarly to the bypass circuit 804 described herein.

Fig. 17 is a circuit diagram illustrating a voltage regulation circuit 950 for providing a boost and native bypass voltage, according to one embodiment. The voltage regulation circuit 950 may be used in any suitable method or apparatus described herein. The voltage regulation circuit 950 receives an input voltage via an input voltage connection 952 and outputs an output voltage via an output voltage connection 954. The voltage regulation circuit 950 is connected to ground 956 (e.g., the negative terminal of the battery to which the input voltage connection 952 is connected).

The voltage regulation circuit 950 functions similarly to the voltage regulation circuit 800 shown in fig. 14 and described above. The voltage regulation circuit includes an inductor 958, an input side capacitor 960, a control unit 962, output side capacitors 964, 966, and output side resistors 968, 970. When the input voltage received through the input voltage connection 952 is greater than or equal to a target output voltage to be supplied to the battery powered device through the output voltage connection 954, the control unit 962 may electrically connect the (vout) terminal with the (vin) terminal, thereby outputting the input voltage received from the battery to the output voltage connection 954. When the input voltage received through the input voltage connection 952 is less than the target output voltage, the control unit 962 may alternatively connect the (SW) input terminal with the (GND) output terminal and the (vout) output terminal, causing a suitable current to flow through the inductor 958, which then drives a current out through the (vout) terminal, causing an accumulation of charge on the output-side capacitors 964, 966, raising the voltage supplied to the output voltage connection 954 in a manner similar to that described herein with respect to the voltage regulating circuit 800. The input side capacitor 960 serves to reduce variations in the input voltage supplied to the inductor 958 and the control unit 962.

Voltage regulation circuitry may be included within the battery powered device to extend the life of one or more batteries used to power the battery powered device. For example, fig. 18 shows a battery powered device 1000 including a voltage regulating circuit 1002 included therein. The voltage regulation circuit 1002 may be configured similarly to other regulation circuits described herein. The battery powered device 1000 includes circuitry and/or elements 1004 that are powered by one or more batteries 1004, which one or more batteries 1004 may be removable, replaceable, and/or rechargeable. As with other conditioning circuits described herein, the voltage conditioning circuit 1002 is configured to extend the life of the one or more batteries 1004 by outputting a conditioned voltage for powering the circuits and/or components 1004 (even when the voltage output by the one or more batteries 1004 falls below a minimum voltage required for normal operation of the circuits and/or components 1004).

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated or designed to achieve the same purpose, may be substituted for the specific embodiments shown. Many modifications of the disclosure will be apparent to those of ordinary skill in the art. For example, the configurations and/or functions described herein with respect to any one of voltage regulator 105, regulator 405, regulator 505, voltage regulator 605, regulation circuit 705, regulation circuit 729, regulation circuit 742, voltage regulation circuit 800, buck converter circuit 850, voltage regulation circuit 900, voltage regulation circuit 950, and the functions described herein (such as the functions described herein with respect to fig. 11-13) may be employed alone or in any suitable combination in methods and/or apparatus for extending battery life. This application is therefore intended to cover any adaptations or variations of the present disclosure.

Claims (23)

1. A method for extending battery life, the method comprising:

receiving a battery electrical power output from the battery, the battery electrical power output having a battery output voltage that decreases from a first battery output voltage to a second battery output voltage;

driving a converter using the battery electrical power output, the converter outputting a converter electrical power having a converter output voltage greater than the second battery output voltage; and

outputting the converter electrical power from one or more output terminals configured to interface with one or more input terminals of a battery powered device, the converter: (a) configured and supported relative to the battery to interface with one or more output terminals of the battery, or (b) embedded within the battery, wherein the converter electrical power output is output through terminals of the battery.

2. The method of claim 1, wherein:

the converter output voltage has a substantially constant magnitude when the battery output voltage decreases from the first battery output voltage to the second battery output voltage; and

the second battery output voltage is less than 70% of the first battery output voltage.

3. The method of claim 1, further comprising outputting the battery electrical power output from the one or more output terminals configured to interface with one or more input terminals of a battery powered device when the battery output voltage decreases from the first battery output voltage to a voltage equal to or greater than a minimum voltage level required for normal operation of the battery powered device.

4. The method of claim 1, further comprising reducing the converter output voltage during at least a portion of the battery output voltage being reduced from the first battery output voltage to the second battery output voltage.

5. The method of claim 4, wherein during the portion of the battery output voltage that decreases from the first battery output voltage to the second battery output voltage, the converter output voltage decreases by less than 10% and the battery output voltage decreases by greater than 30%.

6. The method of claim 1, wherein the converter output voltage is less than the battery output voltage during an initial portion of the battery output voltage decreasing from the first battery output voltage to the second battery output voltage.

7. The method of claim 1, wherein:

the converter includes a boost converter and a buck converter, the boost converter and the buck converter being controlled such that the converter outputs a voltage: a) less than the first voltage, b) greater than the second voltage, and c) less than 10% change when the battery output voltage decreases from the first battery output voltage to the second battery output voltage; and

the second battery output voltage is less than 70% of the first battery output voltage.

8. The method of claim 1, wherein the battery comprises a plurality of individual batteries connected in series.

9. The method of claim 1, wherein the battery is a 9 volt battery with standard adjacent output terminals.

10. The method of claim 1, wherein the battery has a housing and the converter is disposed within the housing.

11. The method of claim 1, further comprising preventing polarity reversal by inhibiting mating between a negative terminal of the battery and a positive input voltage terminal of the converter.

12. The method of claim 1, wherein the battery-powered device comprises the converter.

13. A battery sleeve for extending the useful life of one or more batteries, the battery sleeve comprising:

a positive conductive electrode;

an insulating layer extending below the conductive electrode such that the positive conductive electrode is positioned above a positive terminal of the one or more cells when the sleeve is coupled to the one or more cells, wherein the insulating layer electrically isolates the positive conductive electrode from the positive terminal; and

a voltage regulation circuit adapted to receive a voltage provided by the one or more batteries and produce an increased output voltage on the positive conductive electrode relative to the provided voltage for at least a portion of the useful life of the one or more batteries.

14. The battery cartridge of claim 13 wherein the voltage provided by the one or more batteries decreases from a first battery output voltage to a second battery output voltage over the useful life of the one or more batteries, the second battery output voltage being less than 70% of the first battery output voltage.

15. The battery cartridge of claim 13 wherein the voltage regulation circuit outputs the voltage provided by the one or more batteries to the positive conductive electrode when the voltage provided by the one or more batteries decreases from a first battery output voltage to a voltage equal to or greater than a minimum voltage level required for normal operation of the battery powered device.

16. The battery cartridge of claim 13 wherein the voltage regulating circuit produces an output voltage that is greater than the voltage provided by the one or more batteries, the output voltage produced by the voltage regulating circuit decreasing during a portion of the useful life of the one or more batteries.

17. The battery cartridge of claim 16 wherein during the portion of the useful life of the one or more batteries where the voltage produced by the regulating circuit decreases, the voltage produced by the voltage regulating circuit decreases by less than 10% and the voltage provided by the one or more batteries decreases by greater than 30%.

18. The battery cartridge of claim 13 wherein the voltage produced by the voltage regulation circuit is less than the voltage provided by the one or more batteries during an initial portion of the useful life of the one or more batteries.

19. The battery sleeve of claim 13 wherein:

the voltage regulation circuit includes a boost converter and a buck converter controlled such that the voltage generated by the voltage regulation circuit: a) less than an initial voltage provided by the one or more batteries during the useful life of the one or more batteries, b) greater than a final voltage provided by the one or more batteries at the end of the useful life of the one or more batteries, and c) varies by less than 10% during the useful life of the one or more batteries; and

the final voltage provided by the one or more batteries is less than 70% of the initial voltage provided by the one or more batteries.

20. The battery cartridge of claim 13 wherein the one or more batteries comprise a plurality of individual batteries connected in series.

21. The battery sleeve of claim 13 wherein said one or more batteries comprise a 9 volt battery having standard adjacent output terminals.

22. The battery sleeve of claim 13, further comprising a u-shaped member configured to receive the positive terminal of the one or more batteries when the battery sleeve is coupled with the one or more batteries and to inhibit an electrical connection between the voltage regulation circuit and a negative terminal of the one or more batteries so as to prevent a polarity reversal of the voltage provided by the one or more batteries to the voltage regulation circuit.

23. A battery assembly having an extended service life, the battery assembly comprising:

a housing;

one or more voltage generating units disposed within the housing and providing an output voltage;

a positive voltage terminal;

a negative voltage terminal; and

a voltage regulation circuit disposed within the housing, the voltage regulation circuit receiving the output voltage provided by the one or more voltage generating units and generating an increased output voltage relative to the voltage provided by the one or more voltage generating units over at least a portion of a useful life of the one or more voltage generating units, the voltage regulation circuit being operatively connected to the positive voltage terminal and the negative voltage terminal to output the generated increased output voltage through the positive voltage terminal and the negative voltage terminal.