CN1781229A - Battery management. - Google Patents

Abstract

This invention discloses systems and techniques relating to wireless communication. The systems and techniques relate to an efficient power source for extending battery life. The power source may include first and second batteries and a power management module configured to operate each of the first and second batteries in a pulsed current discharge mode while simultaneously supplying continuous current to a load.

Description

battery management

Related applications

This application claims priority to US Provisional Application Serial No. 60/455,794, filed March 18,2003.

technical field

This disclosure relates generally to wireless communications, and more specifically to battery management techniques in wireless communication devices.

Background technique

Battery life is an important consideration in the design of wireless communication devices. Manufacturers today employ various power management techniques to reduce the average power consumption of a device and thereby extend battery life. For example, efficient power management systems have emerged for second generation (2G) voice communications in wireless communication devices equipped using Code Division Multiple Access (CDMA) technology. The 2G CDMA system is based on the TIA/EIA IS-95 CDMA standard, which includes IS-95A and IS-95B revisions. These standards are well known in the art. These days, such devices with weeks of standby time and hours of talk time are common. This is usually accomplished by subtly switching power to various processing resources.

To meet the growing demand for wireless services and high-speed data services, third generation (3G) mobile services have recently emerged in the telecommunications industry. Much like its predecessor, CDMA provides the platform on which 3G services are provided. The International Telecommunication Union (ITU), together with industry groups from around the world, defined and approved the technical requirements and standards under IMT-2000 (ITU-20 project).

Wireless communication devices with 3G services are feature-rich multi-mode devices capable of supporting voice, high-speed Internet, and multimedia communications. Some common components on high-end devices such as mobile station modems (MSMs) include: an MP3 player, an MPEG-4 decoder, Bluetooth, gpsOne, audio decoder, JPEG encoder/decoder, etc. In many of these installations, voice services are enhanced with live video. Some of these components may inhibit power management schemes that interrupt power as is typically done in devices supporting 2G services. This can lead to a huge increase in average power consumption, with the largest increase in power fed to the baseband circuitry, memory and display. In addition, consumer behavior research shows more attention to long-term connections of various digital services such as cameras and the Internet in the near future.

Various techniques have been proposed to reduce power consumption of wireless communication devices supporting 3G services. Some of the more common approaches include shrinking device technology, caching, optimizing front-end architecture, using direct-conversion transceivers, using down-switching and up-switching, scaling supply voltage (run-time throttling), and reducing average current consumption (run-time frequency throttling and clock gating). These techniques are well known in the art and have had some success in reducing the average power consumption of a device.

In fact, the average power consumption of a device is only one component of battery life. Further increases in battery life can be achieved by improving the efficiency with which the battery delivers energy to various processing resources. The need for battery efficient systems is evident in wireless communications supporting 3G services. In these devices, conventional power management schemes aimed at reducing average power consumption may not provide acceptable battery life. Therefore, there is a need in the art for battery efficient systems that can be used alone or in combination with other power management techniques to increase battery life.

Contents of the invention

In one aspect of the invention, a power supply includes first and second batteries and a power management module configured to operate each of the first and second batteries in a pulsed current discharge mode while supplying power to a load. supply continuous current.

In another aspect of the invention, a power supply includes first and second batteries and means for operating each of the first and second batteries in a pulsed current discharge mode while supplying a continuous current to a load.

In another aspect of the invention, a power supply includes first and second batteries, a switch coupled to the first and second batteries, and a switch control module configured to operate the switch such that Each of the first and second batteries is intermittently coupled to the load.

In another aspect of the invention, a method of supplying current from first and second batteries to a load includes connecting first and second batteries to the load, disconnecting the first battery from the load while maintaining the second battery and the load. connection between the loads, reconnecting the first battery to the load while maintaining the connection between the second battery and the load, and disconnecting the second battery from the load while maintaining the connection between the first battery and the load.

In another aspect of the invention, a wireless communication device includes a processor configured to support wireless communication, first and second batteries, and a power management module configured to operate in a pulsed current discharge mode Each of the first and second batteries is operated while supplying continuous current to the processor.

It is understood that other embodiments of the invention will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described various embodiments of the invention by way of illustration. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various other respects, all without departing from the spirit and scope of the invention. Accordingly, the drawings and detailed description should be regarded as illustrative in nature and not restrictive.

Description of drawings

Aspects of the invention are illustrated by way of example and not limitation in the accompanying drawings, in which:

1 is a block diagram illustrating an example of a wireless communication device having a software-based processor architecture;

2 is a state diagram illustrating an example of various operating states of a wireless communication device;

Figure 3 is a schematic representation of an embodiment of a power control module;

Figure 4 is a flowchart illustrating the operation of an embodiment of a power control module;

Figure 5 is a timing diagram illustrating an example of a battery switching algorithm; and

6 is a flow diagram illustrating an example of a battery switching algorithm.

Detailed ways

The detailed description set forth below in conjunction with the accompanying drawings is intended to be a description of various embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. Each embodiment described in this disclosure is provided merely as an example or illustration of the invention and is not necessarily to be construed as preferred or preferred over other embodiments. The detailed description includes specific details to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the present invention. Acronyms and descriptive terms are used for convenience and clarity only and are not intended to limit the scope of the invention.

Wireless communication devices typically use batteries to power the electronics and various user interfaces (hereinafter collectively referred to as "loads"). The ability of a battery to provide a constant current source for an extended period of time depends on (1) the efficiency of the battery and (2) the average power consumption of the device. Maximum battery life is achieved by maximizing battery efficiency and reducing average power consumption.

A lithium-ion battery with a rated capacity of 1600 milliampere hours (mAh) typically has an efficiency in the range of 89-91% when supplied with a constant current. This means that theoretically the battery can produce about 1440 milliamps (mA) for 1 hour (1600mAh x .90). Alternatively, the battery can produce 144mA for 10 hours or 288mA for 5 hours or 720mA for 2 hours or 2880mA for 30 minutes. Although not perfectly linear, the above calculations are fairly accurate within the normal range of battery usage. Thus, it can be readily observed that for a given efficiency, battery life can be extended by implementing various power management techniques that reduce the average current consumption.

Battery life can also be extended by increasing battery efficiency. For example, if the efficiency of a battery with a rated capacity of 1600mAh can be increased from 90% to 98%, then the deliverable capacity of the battery can be increased from 1440mAh to 1568mAh (1600mAh x .98). Therefore, battery life can be improved by 8-9% regardless of any power management techniques implemented.

One way to increase the efficiency of a battery is to operate it in a pulsed current discharge mode. The battery may be operated in a pulsed current discharge mode by intermittently connecting the battery to a load. For the purposes of this disclosure, the term "intermittently" means connecting the battery to the load and then disconnecting the battery from the load at regular or irregular intervals. Furthermore, a "connection" to a load may be direct or, where appropriate, indirect, such as through intervening or intervening devices or other means. For a lithium-ion battery with a nominal capacity of 1600mAh, battery efficiencies in the range of 97.5-99.95% can be achieved by operating the battery in pulse discharge mode.

A wireless communication device using a battery operating in a pulsed current discharge mode can provide extended battery life and thus increase the mobility of the device. The challenge for designers is that hardware may require uninterrupted power to support various modes of operation. To illustrate this concept, the battery configuration is described in the context of a CDMA wireless communication device supporting 3G services. While the inventive aspects disclosed herein are well suited for this application, those skilled in the art will readily appreciate that the inventive aspects are equally applicable to other devices. Accordingly, any reference to a CDMA wireless communication device is intended as illustration only, with the understanding that the various inventive aspects described in this disclosure have wide-ranging applicability.

1 is a conceptual block diagram illustrating one possible configuration of a wireless communication device 102, commonly referred to as a subscriber station. As will be appreciated by those skilled in the art, the precise configuration of a wireless communication device may vary depending on the particular application and overall design constraints. The wireless communication device 102 may include a power control module 104 capable of receiving power from various sources such as batteries, external chargers, adapters, and others. The power control module 104 may be used to generate all the regulated voltages required to power the various user interfaces 106 , processor 108 and analog front end (AFE) 110 . The power control module 104 can also be used to monitor and control the various power sources, detect which power sources are applied, verify that they are within acceptable operating limits, and coordinate recharging of the batteries while maintaining the supply voltage.

The various user interfaces 106 may include a backlight that may be used for keypad and display functions or an LCD driver 112 with brightness (current) control, but may be a user-defined generic driver. A separate vibrator and ring driver 114 may be used to alert the user of an incoming call. User interface 106 may also include an audio circuit 116 for voice communication. These user interfaces 106 can also be used to support 2G services including voice and low-rate data communications. In some embodiments, such as to support 3G services, the user interface 106 may also be used to support high speed Internet connections, such as may be the case with an integrated web browser.

Processor 106 may be a software-based processor system or any other configuration known in the art. In the embodiment shown in FIG. 1, the software-based processor has a microprocessor 118 and memory 120 at its core. Microprocessor 118 may provide a platform for running software programs that, inter alia, handle all housekeeping functions for various user interfaces 104, coordinate command and control signaling functions through a base station (not shown), and control wireless communication devices 102 call processing status. Memory 120 may be used to provide storage for the device's operating system and specialized features such as a phonebook and other similar features.

A digital signal processor (DSP) 122 may be implemented with an embedded communications software layer that runs application-specific high-speed algorithms to reduce processing demands on the microprocessor 118 . These specific high speed algorithms may include encoding and modulating voice and data generated by audio circuitry 116 or entered from a keyboard prior to transmission via AFE 110 to a remote user. DSP 122 may also decode and demodulate voice and data received from remote users via AFE 110 before being passed to audio circuitry 116 or presented on a display. The software layer may also be used to interface between the DSP hardware and the microprocessor 118 and may provide low level services such as allocation of resources to allow higher level software programs to run.

2 is a state diagram illustrating call processing states of a wireless communication device supporting 3G services. When power is initially applied to a device, it may enter an initialization state 202 . During the initialization state 202, the apparatus is operable to process pilot and sync channels to acquire system timing. Once the device has fully acquired system timing, it may enter an idle state 204 .

In the idle state 204, the device can be used to monitor the paging channel for incoming calls. To save battery power, time slot paging can be used. In a slotted paging configuration, the wireless communication device and the base station agree in which time slots the device will be paged. A device may power down some of its processing circuits and enter sleep mode during unassigned time slots. In sleep mode, a typical wireless communication device may draw roughly between 200 μA and 400 μA of current. During the assigned time slot, the device wakes up and monitors the paging channel. The length of the assigned time slot depends on the paging type. When the device wakes up, the registry is also part of the idle state. Registration is the method by which a device makes the whereabouts of the device known to the base station. Typically, the current required to monitor the paging channel and register during the idle state may be roughly between 55mA and 65mA.

When a device receives a page or initiates a call, it may enter the access state 206 to negotiate call parameters with the base station by exchanging signaling messages. Once the call is agreed upon, the device can be directed to the communication channel to support the call. During a call, the device may enter a communication state 208, which typically requires an average current of about 120-150 mA. A typical device supporting 3G services may draw an average of roughly 65-250mA, depending on the type of application. Additionally, the type of current discharge distribution required to support an application may vary. For example, a camera might be supported with a pulsed current discharge profile while an MP3 player would require a constant current discharge profile.

As previously explained, battery life can be extended by operating the battery in a pulsed current discharge mode. In many communication devices, software can be modified to accommodate this type of operation. In the case of CDMA devices operating in a communication state, software modifications to support batteries operating in pulsed current discharge mode may, especially in time sensitive applications, adversely affect the performance of the device. Therefore, an efficient battery management scheme can be implemented by switching two or more batteries alternately to the load.

3 is a schematic representation of a power control module 302 configured to alternately switch two batteries 304a and 304b operating in pulse discharge mode to a load (not shown). The embodiment shown in FIG. 3 may be a select configuration in existing legacy devices that best utilizes existing electronic devices. In future generations of wireless devices, it may be more convenient to use the integrated package as a power source. The integrated package may include a power control module 302 and two batteries 304a and 304b operating in a pulse discharge mode in a single housing or enclosure. Two internal batteries can be switched alternately from the case or case to a single output to provide a constant current source.

Referring to Figure 3, the load can be powered by various sources: an external power source (not shown) and batteries 304a and 304b. The power control module 302 can be used to coordinate these power sources—detecting which power sources are applied, verifying that they are within acceptable operating limits, and coordinating recharging of batteries 304a and 304b while maintaining supply voltage to the load.

The battery charger 306 can be used to detect whether the wireless communication device is connected to an external power source. If the battery charger 306 detects an external power source, it can apply the appropriate gate voltage to a field effect transistor (FET) 308 to connect the external power source to the load. An external power source can also be used to charge the two batteries 304a and 304b. This may be accomplished by providing a control signal from the battery charger 306 to the switch control module 310 . In response to the control signal, the switch control module 310 can connect the batteries 304a and 304b to an external power source through the switch 311 . In the embodiment shown in FIG. 3, switch 311 may be constructed using two FETs 312a and 312b.

In the absence of an external power source, the battery charger 306 can be used to bias the FET 308 to disconnect the external power input line from the load. A control signal may also be provided from battery charger 306 to switch control module 310 to indicate that batteries 304a and 304b are the only power sources. In response to the control signal, the switch control module 310 can identify the state of the wireless communication device and alternately switch the two batteries 304a and 304b to the load according to the battery voltage, so that each battery operates in a pulsed current discharge mode.

The voltage sense feedback resistor 314 can be used to determine the state of the wireless communication device. The voltage drop across voltage sense feedback resistor 314 can be used by differential amplifier 316 to generate a voltage representative of the total current supplied to the load. This voltage, along with the battery voltage, may be alternately supplied to the switch control module 310 through the multiplexer 318 . Alternatively, the three voltages may be directly applied to the switch control module 310 .

The operation of switch control module 310 may vary according to specific performance parameters and overall design constraints. Those skilled in the art can readily implement a switch control module for their particular application. The operation of an embodiment of the switch control module 310 will be described by way of example and without limitation of various other embodiments within the scope of the invention with reference to FIG. 4 .

Referring to FIGS. 3 and 4 , the switch control module 310 may be configured to first compare the voltages of the two batteries in step 402 . Both cells should be at the same potential. A voltage difference between two cells can cause the cell with the higher potential to reduce to the lower voltage of the two, thus reducing the amount of current passing to the load. If there is a significant voltage difference between the two batteries, the switch control module 310 uses the battery with the higher voltage to supply current to the load until both batteries are at the same voltage. More specifically, if the voltage (V _A ) of the first battery 304a exceeds the voltage (V _B ) of the second battery 304b, the switch control module 310 applies the appropriate gate voltage to the FETs 312a and 312b in step 404 to force the first FET 312a goes into a conducting mode and forces the second FET 312b into a non-conducting mode. This configuration results in the first battery 304a being connected to a load. Conversely, if the voltage (V _B ) of the second battery 304b exceeds the voltage (VA) of the first battery 304a, _then the switch control module 310 applies the appropriate gate voltage to the FETs 312a and 312b in step 406 to force the first FET 312a Enters a non-conductive mode and forces the second FET 312b into a conductive mode. Therefore, the second battery 304b is connected to the load. This procedure continues until the battery voltages are equal, V _A = V _B .

Once the battery voltages are equal, V _A =V _B , the switch control module 310 may then determine the status of the wireless communication device in step 408 . This can be accomplished by monitoring the voltage output from differential amplifier 316 . The default condition of the switch control module 310 may declare the wireless device to be in an idle state unless the switch control module 310 detects a significant current draw from the battery for an extended period of time. As explained in more detail above, time slot paging may be used during idle states to conserve battery power. In a slotted paging configuration, the wireless communication device and the base station agree in which time slots the device will be paged. A device may enter sleep mode during unassigned time slots. During sleep mode, the current drawn from the battery is insignificant. The current drain on the battery only becomes noticeable when the wireless device wakes up in the assigned time slot to check for pages. Thus, the battery operates effectively in a pulsed discharge mode, and thus can be continuously connected to the load. More specifically, if the voltage from differential amplifier 316 does not exceed the threshold voltage for a predetermined period of time, switch control module 310 may apply an appropriate gate voltage to FETs 312a and 312b in step 410 to force both of them into conduction mode . This configuration results in batteries 304a and 304b being connected to the load.

On the contrary, if the switch control module 310 detects that the voltage generated by the differential amplifier 316 exceeds the threshold voltage within a predetermined period, the switch control module 310 determines that the wireless device is in the communication state. In the communication state, the switch control module 310 alternately switches the two batteries 304 a and 304 b to the load in step 412 .

The switching method should be configured to avoid power glitches. This can be achieved by setting the duty cycle of each battery to a value greater than 50% such that the idle battery is connected to the load before the other batteries are disconnected in a make-before-break fashion. Typically, each battery should have a duty cycle between 55% and 100% and is factory programmable by the manufacturer or distributor. The switching frequency and remaining capacity of the battery can also be programmed into the device. Typically, the margin should be between 5% and 10%.

An example of a switching waveform for a battery is shown in FIG. 5 . The waveforms in FIG. 5 represent the voltages applied to the gates of FETs 312a and 312b. To maintain some degree of overlap, the maximum allowable delay between the rising edges of the gate voltages applied to the two FETs is ( _Ton - margin) and the maximum allowable delay is ( _Toff + margin).

Switching waveforms can be generated in various ways. An example will be explained by the flowchart of FIG. 6 . Referring to FIG. 3 and FIG. 6 , once the switch control module 310 determines that the wireless device is in a communication state, it may reset an internal timer (not shown) in step 602 . Once the internal timer is reset, the following algorithm can be executed by the switch control module 310 .

In step 604, the switch control module 310 can determine whether the internal timer is less than ( _Ton - _Toff -margin). If the internal timer is less than ( _Ton - _Toff -margin), switch control module 310 may apply appropriate gate voltages to FETs 312a and 312b in step 606 to force both of them into conduction mode. This configuration results in batteries 304a and 304b being connected to the load. Once the internal timer reaches ( _Ton - _Toff -margin), the switch control module 310 may proceed to step 608 .

In step 608, the switch control module 310 may determine whether the internal timer is less than ( _Ton -margin). When the internal timer is less than ( _Ton -Margin), the switch control module 310 may remove the gate voltage to the first FET 312a in step 610 to disconnect the first battery 304a from the load. Once the internal timer reaches ( _Ton - _Toff -margin), the switch control module 310 may proceed to step 612 .

In step 612, the switch control module 310 may determine whether the internal timer is less than ( _Ton ). When the internal timer is less than ( _Ton ), the switch control module 310 may apply an appropriate gate voltage to the first FET 312a in step 614 to reconnect the first battery 304a to the load. Once the internal timer reaches ( _Ton -Margin), the switch control module 310 may proceed to step 616 .

In step 616, the switch control module 310 can determine whether the internal timer is less than ( _Ton + _Toff ). When the internal timer is less than ( _Ton + _Toff ), then the switch control module 310 may remove the gate voltage to the second FET 312b in step 618 to disconnect the second battery 304b from the load. Once the internal timer reaches ( _Ton + _Toff ), the switch control module 310 returns to step 602 to reset the internal counter and generate another cycle of the switching waveform.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein can be implemented or performed by: a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in alternative embodiments, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, eg, a DSP in combination with a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

The methods or algorithms described in connection with the embodiments disclosed herein may be directly embodied in hardware, software modules executed by a processor, or a combination of both. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM or any other form of storage medium known in the art. A storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In alternative embodiments, the storage medium may be integrated with the processor. The processor and storage medium can reside in an ASIC. The ASIC may reside in the subscriber station or elsewhere. In alternative embodiments, the processor and storage medium may exist as discrete components within the subscriber station or elsewhere in the access network.

The foregoing description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (39)

1. power supply, it comprises:

First and second battery; With

Each while that one power management module, described power management module are configured to operate under a pulse current discharging pattern in described first and second battery is supplied continuous current to a load.

2. power supply according to claim 1, wherein said power management module comprises: a switch control module; With a switch, described switch is configured under the control of described switch control module described first and second battery is couple to described load off and on.

3. power supply according to claim 2, wherein said switch comprises: one first switch, described first switch are configured under the control of described switch control module described first battery is couple to described load off and on; With a second switch, described second switch is configured under the control of described switch control module described second battery is couple to described load off and on.

4. power supply according to claim 3, each self-contained field-effect transistor of wherein said first and second switch.

5. power supply according to claim 3, wherein said power management module is through further being configured to measure the described electric current that is fed to described load, and described switch control module is through further being configured to control described switch with the variation of described measurement electric current.

6. power supply according to claim 5, wherein said switch control module is through further being configured to control described switch, if make that described measurement electric current is lower than a threshold value, so described first and second battery is couple to described load continuously.

7. power supply according to claim 5, wherein said switch control module is through further being configured to control described switch, if make that described measurement electric current arrives a threshold value in a period of time, each in so described first and second battery is couple to described load off and on.

8. power supply according to claim 3, wherein said switch control module make that through further being configured to control described switch described first battery is couple to described load before removing described second battery from described load.

9. power supply according to claim 1, wherein said switch control module is through further being configured to variation control with the voltage of measuring at described first and second battery place as described switch.

10. power supply according to claim 9, wherein said selection module is couple to described load through further being configured to control described switch with of having in described first and second battery of ceiling voltage.

11. a power supply, it comprises:

First and second battery; With

Be used for the member of each while of described first and second battery of operation under a pulse current discharging pattern to load supply continuous current.

12. power supply according to claim 11, each the described member that wherein is used under a pulsed discharge pattern described first and second battery of operation comprises: one first switch, described first switch are configured to described first battery is couple to described load off and on; One second switch, described second switch are configured to described second battery is couple to described load off and on; With the member that is used to control described first and second switch.

13. power supply according to claim 12, each the described member that wherein is used under a pulsed discharge pattern described first and second battery of operation further comprises the member that is used to measure the described electric current that is fed to described load, the described member that is used to respond described first and second switch of described measurement Current Control.

14. power supply according to claim 12, the described member that wherein is used to control described first and second switch is configured to before removing described second battery from described load described first battery is couple to described load.

15. power supply according to claim 12 wherein is used to control the voltage of the described member response of described first and second switch in each place's measurement of described first and second battery.

16. a power supply, it comprises:

First and second battery;

One switch, described switch are couple to described first and second battery; With

One switch control module, described switch control module is configured to operate described switch, makes in described first and second battery each be couple to a load off and on.

17. power supply according to claim 16, wherein said switch comprises the second switch that first switch and that is couple to described first battery is couple to described second battery, and described switch control module is couple to described load through further being configured to control described first and second switch off and on described first and second battery.

18. power supply according to claim 17, each self-contained field-effect transistor of wherein said first and second switch.

19. power supply according to claim 16, it further comprises the member that is used to measure the described electric current that is fed to described load, and wherein said switch control module is through further being configured to control described switch with the variation of described measurement electric current.

20. power supply according to claim 19, wherein said switch control module is through further being configured to control described switch, if make that described measurement electric current is lower than a threshold value, each in so described first and second battery is couple to described load continuously.

21. power supply according to claim 19, wherein said switch control module is through further being configured to control described switch, if make that described measurement electric current strides across a threshold value in a period of time, each in so described first and second battery is couple to described load off and on.

22. power supply according to claim 16, wherein said switch control module through further being configured to control described switch, make that described first battery is couple to described load before removing described second battery from described load.

23. power supply according to claim 16, described switch is controlled in the variation of the voltage of wherein said switch control module through further being configured to measure with each place in described first and second battery.

24. power supply according to claim 23, wherein said switch control module is couple to described load through further being configured to control described switch with of having in described first and second battery of ceiling voltage.

25. one kind from the method for first and second battery to a load supply of current, it comprises:

Described first and second battery is connected to described load;

Disconnect described first battery from described load and keep described connection between described second battery and the described load simultaneously;

Described first battery is reconnected to described load keep described connection between described second battery and the described load simultaneously; With

Disconnect described second battery from described load and keep described connection between described first battery and the described load simultaneously.

26. method according to claim 25, wherein form described connection between described first battery and the described load, and form described connection between described second battery and the described load by one second field-effect transistor by one first field-effect transistor.

27. method according to claim 25, it further comprises judges that the described electric current that is fed to described load strides across a threshold value in a period of time, respond described judgement and disconnect described first battery from described load.

28. method according to claim 25, it further comprises judges that a voltage of measuring at the described second battery place surpasses a voltage of measuring at the described first battery place, responds described judgement and disconnects described first battery from described load.

29. method according to claim 28, it further comprises described voltage that judgement measures at described second battery and equals the described voltage measured at the described first battery place substantially after disconnecting described first battery from described load, the described judgement that the described measuring voltage of response at described first and second battery place equates substantially reconnects to described load with described first battery.

30. a radio communication device, it comprises:

One processor, it is configured to support of wireless communication;

First and second battery; With

One power management module, its each while that is configured to operate under a pulse current discharging pattern in described first and second battery is supplied continuous current to described processor.

31. radio communication device according to claim 30, wherein said power management module comprises a switch control module and a switch, and described switch is configured under the control of described switch control module described first and second battery is couple to described processor off and on.

32. radio communication device according to claim 31, wherein said switch comprises: one first switch, and it is configured under the control of described switch control module described first battery is couple to described processor off and on; With a second switch, it is configured under the control of described switch control module described second battery is couple to described processor off and on.

33. radio communication device according to claim 32, each self-contained field-effect transistor of wherein said first and second switch.

34. radio communication device according to claim 32, wherein said processor is operated under an idle state or a communications status through further being configured to, and described switch control module is through further being configured to control described switch with the variation of described processor state.

35. radio communication device according to claim 34, wherein said switch control module is through further being configured to control described switch, if make that described processor is in described idle state, so described first and second battery is couple to described processor continuously.

36. radio communication device according to claim 34, wherein said switch control module is through further being configured to control described switch, if make that described processor is in described communications status, each in so described first and second battery is couple to described processor off and on.

37. radio communication device according to claim 34, wherein said power control module is through further being configured to judge described processor state with the variation of the described electric current that is fed to described processor.

38. radio communication device according to claim 30, described switch is controlled in the variation of the voltage of wherein said switch control module through further being configured to measure with each place in described first and second battery.

39. according to the described radio communication device of claim 38, wherein said selection module is couple to described load through further being configured to control described switch with of having in described first and second battery of ceiling voltage.

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