Patent Application
20070152630
This disclosure relates in general to portable power devices, and more particularly to battery replacement without loss of power to an electronic device.
The makers of mobile communication devices, including those of cellular telephones, are increasingly adding functionality to their devices. For example, cellular telephones include features such as still and video cameras, video streaming and two-way video calling, email functionality, Internet browsers, music players, FM radios with stereo audio, and organizers. Bluetooth enabled cellular telephones may be PC compatible so that files generated or captured on the mobile communication device may be downloaded to a PC. Likewise, data from a PC or other source may be uploaded to the mobile communication device. Cellular telephones in particular are becoming more than simply mobile communication devices. They are evolving into powerful tools for information management.
With the increased functionality of mobile communication devices, users are more likely to consume significant power for extended periods of time. At the same time consumers welcome increased functionality in mobile communication devices, consumers also prefer smaller sized mobile communication devices. In the meantime though, the power burden has outpaced battery technology. Accordingly and unfortunately small batteries cannot store enough power to maintain functionality for extended periods of time.
As users tend to use their devices for extended periods of time, interruptions due to depleted batteries can be extremely inconvenient. A user may not have immediate access to an electrical outlet or car lighter to recharge the device battery. In the event that a user is able to attach a charger to the device, a charger can restrain the user's mobility. With a loss of power, a user may be forced to turn off the mobile communication device either intentionally or inadvertently. In this way, a voice or video call could be inconveniently interrupted. After the device is off, a user may change discharged batteries and then restore power to the device. When power is restored, a high functionality “smart” device may take over a minute to reboot and become operational.
In a high current drain device, such as a hand held cellular telephone, it would be beneficial to enable a user to hot swap device batteries. That is, users would benefit from continuous operability were batteries exchangeable in a device without loss of power to the device.
Described are methods and devices in a battery powered electronic device for hot swapping batteries. That is, a user may maintain the power and thus operations of the device while exchanging a first battery for a second battery therein. Accordingly, without powering down the device, its current battery may be removed and replaced by another.
The device includes a battery holder or housing with at least two battery connectors and a circuit for providing continuous power to the device during a battery swap. To initiate the battery swap, the first battery is partially moved out of the battery holder in a predetermined direction to break contact with a first connector while maintaining contact with a second connector. To further the swap, the second battery is partially inserted into the battery holder in the predetermined direction so that the second battery is received by the battery holder and makes contact with the first connector. In one embodiment when the second battery moves in the predetermined direction within the battery holder, it pushes the first battery to effect the partial moving of the first battery out of the battery holder. Each battery is configured to maintain contact with one of the battery connectors substantially simultaneously during the replacement process.
In one embodiment, a circuit of the device includes battery connectors for the first and second batteries that can be configured with a charger circuit for charging the first battery while the first battery is partially removed from the battery holder, and for charging the second battery while the second battery is partially received into the battery holder, in either order.
The battery configuration, in one embodiment, includes contacts that are elongate contacts located on the bottom side of the first battery or located on the lateral sides of the battery. In another embodiment, the battery configuration includes c-clip contacts configured to make contact with connectors on the inside walls of the battery holder.
The instant disclosure is provided to further explain in an enabling fashion the best modes of making and using various embodiments in accordance with the present invention. The disclosure is further offered to enhance an understanding and appreciation for the invention principles and advantages thereof, rather than to limit in any manner the invention. The invention is defined solely by the appended claims including any amendments of this application and all equivalents of those claims as issued.
It is further understood that the use of relational terms, if any, such as first and second, top and bottom, and the like are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Much of the inventive functionality and many of the inventive principles are best implemented with or in software programs or instructions and integrated circuits (ICs) such as application specific ICs. It is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. Therefore, in the interest of brevity and minimization of any risk of obscuring the principles and concepts according to the present invention, further discussion of such software and ICs, if any, will be limited to the essentials with respect to the principles and concepts within the preferred embodiments.
The device 102 is shown with a single battery 104 positioned in the device battery holder or housing 110. Two battery connectors 103 and 105 of the device 102 and the battery contacts 112 of the battery 104 are shown in phantom and will be discussed in detail below. The battery holder 110 can be in any suitable configuration recessed or not, and can be adapted to provide mechanical latching 115 and/or 116 to engage the battery 104 in the predetermined direction 120 and to engage a second battery in the predetermined direction 120. The mechanical latching can be a spring or tension tab that prevents the battery from being moved, in the instant embodiment, to the right. The battery may be allowed to move linearly in a direction to the left. Of course, depending upon the device battery housing design, the direction of movement of the battery may be in any unidirectional manner, for example, from left to right or down or up. It is further understood that any type of latching mechanism to engage the first battery in the predetermined direction and to engage the second battery in the predetermined direction is within the scope of this discussion.
In
The lower right corner of the bottom 312 of the housing includes an optional lift up or sliding door 316 that covers, for example, the device's SIM card. As mentioned above, by partially moving, that is, partial removal of, the first battery out of the battery holder in a predetermined direction, the first battery may break contact with the first connector 303 while maintaining contact with the second connector 305. With the first battery partially removed and without inserting a second battery, the door 316 may be accessed and opened. Accordingly, a user may be able to replace a SIM card without powering down the device since the first battery can be supplying power to the device through the second connector 305. Once the SIM card operation is complete, the first battery may be fully reinserted, that is, moved back into the position shown in
The elongate contacts 404 may be disposed in parallel battery contact channels 410, 411, 412, 413. Corresponding contacts may be disposed in a first battery connector 303 and a second battery connector 305. Each of the corresponding contacts may be adapted to slide along, and make contact with, an appropriate elongate contact 404 disposed in a battery contact channel 410, 411, 412, 413. While the elongate contacts 404 are depicted as extending the width of the battery, it may suffice that their length reaches the span of the connectors 303 and 305.
In one embodiment, c-clips 604 can be single contact pairs that are separate contacts on the top of the slot and the bottom of the slot. Interconnects between contacts are shown in dashed outline in
In another embodiment, the c-clip 605 is configured with redundant contact pairs for “make or break” (connecting or disconnecting of the battery to the electronic device) at the top of the slot and the bottom of the slot. Here the interconnects may also connect corresponding c-clip contacts at the top and bottom of the slot. It may be found that there is higher reliability inherent in a “c” shaped contact design, especially with redundant contact pairs as shown at 605. The higher reliability contacts can be used for plus and ground connections. In the c-clip embodiment, a mechanical latch or tab (not shown) can provide one way locking as well.
The following
The flowchart of
When the battery makes contact with the first connector only, the battery powered electronic device is powered by the battery through its contact with the first connector at step 706. As the battery moves into normal position in the battery holder, it makes contact with the second connector, and shorts a control pin to ground 708. In addition, some contacts of the second connector may monitor and alter the condition of the battery (for example by disabling charging or discharging of the battery). The battery connector circuit is configured so that when the control pin is shorted to ground, power can be drawn from the battery through the second connector at step 710. The elongate connectors of the first battery span both the first connector and the second connector of the battery holder at step 710.
Insertion of a second battery causes the first battery to be pushed off the first connector, remaining connected to the second connector. For a short time, neither battery may make contact with the first connector. Continued insertion of the second battery at step 712 results in the second battery making contact with the first connector while the first battery can continue to make contact with the second connector at step 714. If the first battery can make contact with the second connector, power may continue to be drawn from the first battery through the second connector.
With sufficient insertion of the second battery into the battery holder, the second battery pushes the first battery over and opens the connection between the control pin and ground at step 716. The first battery may no longer make electrical contact with either of the two battery connectors. At the same time, the second battery may continue to make contact with the first connector but may not yet have made contact with the second connector. Comparable to the situation discussed above in connection with step 706, the battery powered electronic device may be powered by the second battery through its contact with the first connector. Steps 708 and 710 may be executed to seat the second battery into the battery holder in a normal position. The first battery may be completely removed.
A different sequence of steps may be executed following step 710 than those described above. In a step 718, the first battery may be pushed over without insertion of a second battery. For example, a user may wish to gain access to a SIM module or other component accessible through the battery holder or battery compartment. One way latching may be configured so that the battery may be returned to a normal position after access to the SIM module, for example, is no longer needed. As a result of step 718, the battery may make contact with the second connector only, and the battery powered electronic device may be powered through the second connector 720. With continued pushing, the battery may be pushed off the second connector to break the connection between the control pin and ground 722. The battery may be removed from the battery powered electronic device, restoring the configuration of step 702.
The following discussion provides more details of the circuit of
A second connector 805 includes five contacts 864, 865, 866, 867, 868 to make contact with elongate contacts of a battery. Contact 864 is connected to the first of a pair of back-to-back p-channel MOSFETs 812 in a common-drain configuration, similar to the back-to-back MOSFETs 806. Contact 865 is connected to circuit components for data communication with a microprocessor and other circuitry that may be included with a battery. Similarly, contact 866 is connected to circuit components that may process output of a thermistor included with a battery. Contact 857 is a control pin connected to circuit components to control the back-to-back MOSFET pairs 806 and 812, as discussed below. Contact 858 is connected to ground.
For the purpose of discussing operation of a switch 818, two circuit nodes C and D are indicated at 814 and 816, respectively. The switch 818 may be a MOSFET or other suitable device operable as a switch. In
The previously mentioned pairs of back-to-back MOSFETs 806 and 812 each have their gates electrically connected together. MOSFET pair 806 has its gates together connected to node D. The value of the voltage of node D controls whether MOSFET pair 806 is in a conducting state or not, as explained below. MOSFET pair 812 has its gates together connected to node C. The value of the voltage of node C controls whether MOSFET pair 812 is in a conducting state or not.
Two pull-up resistors 820 and 822 with values of, for example, 1 mega ohm, are provided between the potential determined by contact 854, labeled VbattB in
The circuit of
As mentioned above, operation of the circuit of
Contacts 867 and 868 are not connected together, since the battery is only partly inserted into the battery holder. Thus, no current flows through the resistor at 820 so that node C also has a potential of V1. Then the gate of n-channel MOSFET 818 is sufficiently positive with respect to its source to bring the MOSFET into conduction, driving node D substantially to ground potential. Current can flow through back-to-back p-channel MOSFETs 806 because the gate-source voltage drop there is sufficiently negative. Thus Vbatt, at connection 824, is substantially VbattB, and the battery powered electronic device is powered through the first connector 803.
With further insertion of the battery into the battery holder, the battery makes contact with the second connector 805. A contact of the battery shorts control pin contact 867 to ground contact 868. Shorting of the control pin to ground brings node C to ground potential, substantially turning off MOSFET 818 and therefore bringing node D to a potential of substantially VbattB. The gate-source voltage drop for MOSFET pair 806 may now be substantially zero, cutting off current flow through the MOSFET pair 806.
At substantially the same time that an elongate contact of the battery shorts control pin contact 867 to ground contact 868, another elongate contact of the battery may make electrical connection with contact 864. VbattA now has a non-zero value V1. The gate-source voltage drop of back-to-back p-channel MOSFET pair 812 can be negative, so MOSFET pair 812 can conduct. Thus Vbatt at connection 824 can be substantially VbattA, and the battery powered electronic device is powered through the second connector. The battery may be adjusted into its normal position, as discussed above in connection with step 710 of
It is appreciated that capacitor 826 provides charge to connection 824 during the short time, if any, that neither MOSFET pair 806 nor MOSFET pair 812 is in a conducting state. Moreover, capacitor 826 may smooth abrupt changes in voltage during battery insertion and battery swaps. In this regard, it may function in this circuit as a low pass filter or power supply capacitor.
With insertion of a second battery, the first battery may be pushed off the first connector 803. The battery powered electronic device still can be powered by the first battery so long as control pin 867 is shorted to ground contact 868 and the potential V1 of the first battery is sufficiently positive. The battery powered electronic device may continue to be powered through the second connector until the first battery is pushed far enough out of the battery holder that connection between control pin 867 and ground contact 868 is broken. Once this happens, the situation is the same as previously described with a battery only partially inserted into the battery holder. It is appreciated that here too, capacitor 826 may act to provide charge to connection 824 and smoothing abrupt transitions in the voltage that may be otherwise supplied to the battery powered electronic device.
Many of the components shown in
One difference with
Additional circuit components provide logic configured to control the operation of the circuit, that is, whether power is to be supplied to the battery powered electronic device through the first battery connector 903 or through the second battery connector 905. Many of these circuit components can accept input or supply output whose values may be considered as logic levels, this is, 0 or 1, and denoted in uppercase. The additional components include a single-pole double-throw switch 930 coupled to contacts 956 and 966 for thermistor output. The switch is controlled through a control line 932 whose logic level is denoted THERMCNTL, and its output provided on an output line 934 to a thermistor analog-to-digital converter (ADC) channel.
An inverter 936 with its input connected to node C supplies output to the commonly connected gates of the pair of back-to-back p-channel MOSFETs 906. Inverter 936 can provide similar switch functionality as switch 818 in the circuit of
The charge enable line 942 provides for selection of battery to charge, when two batteries are in the battery holder and a charger is connected to the battery powered electronic device. When CHRGB_EN has a value of 0, a battery making contact with the second connector can be charged. If a battery makes contact with the first connector, but no battery makes contact with the second connector, the battery can be charged through the first connector. When CHRGB_EN is 1, the battery connected to the first connector can be charged. If no battery is connected to the first connector, a battery connected to the second connector can be charged.
CONA, CONB, PATH, and CHRGB_EN together provide a description of circuit operation, shown in the following truth table.
It is understood that CONA has a value 0 when control pin 967 is shorted to ground contact 968 and has a value of 1 otherwise, and CONB likewise has a value 0 when control pin 957 is shorted to ground contact 958 and has a value of 1 otherwise. Thus, if contacts of a single battery span both the first connector 903 and the second connector 905, CONA and CONB can both be 0. The behavior of the circuit depends on the value of CHRGB_EN. If CHRGB_EN is 0 and CONA is 0, then PATH is 0 so that back-to-back p-channel MOSFETs 912 conduct. Because of inverter 936, back-to-back p-channel MOSFETs 906 do not conduct. Thus, the battery powered electronic device may be powered through the second connector 905.
If CHRGB_EN is 1 and both CONA and CONB are 0, then PATH has a value of 1 so that back-to-back p-channel MOSFETs 912 do not conduct. Because of inverter 936, back-to-back p-channel MOSFETs 906 conduct. The battery powered electronic device is then powered through the first connector 903.
In the case where no battery makes contact with the first connector 903, but contact is made with the second connector 905, CONA is 0, CONB is 1, and PATH is 0. The battery powered electronic device therefore is powered through the second connector 905. In the case where no battery makes contact with the second connector 905, but contact is made with the first connector 903, CONA is 1, CONB is 0, and PATH is 1. The battery powered electronic device can then be powered through the first connector 903.
When no battery makes contact with either the first connector or the second connector (CONA is 0 and CONB is 0), then PATH is 0 and the electronic device is ready to be powered through the second connector after a battery is inserted.
In a third battery configuration 1030, the second battery 1006 has been inserted far enough into the battery holder 1002 that it makes contact with the first connector 1003, and the first battery 1004 elongate contacts 1012 continue to make contact with the second connector 1005. In the fourth battery configuration 1040, the elongate contacts 1012 of the first battery 1004 have broken contact with the second connector 1005, and the second battery 1006 continues to make contact with the first connector 1003 but has not yet made contact with the second connector 1005. Finally, when the second battery 1006 is fully inserted (not shown) it can make normal contact with both connectors 1003 and 1005.
It is understood that, although
This disclosure is intended to explain how to fashion and use various embodiments in accordance with the technology rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to be limited to the precise forms disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principle of the described technology and its practical application, and to enable one of ordinary skill in the art to utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally and equitable entitled.
