WO1997003534A1

WO1997003534A1 - Battery powered device

Info

Publication number: WO1997003534A1
Application number: PCT/SG1996/000006
Authority: WO
Inventors: Geok Leng Tan; Venkatesham Arvapally; Wing Cheong Ip; Thomas Sandy Panicker
Original assignee: Goldtron Telecommunications Pte Ltd.
Priority date: 1995-07-11
Filing date: 1996-06-25
Publication date: 1997-01-30
Also published as: CN1192842A; CA2226513A1; SG35538A1; AU6248196A; GB2317306A; ZA965608B; GB9725962D0

Abstract

A battery powered portable electronic device includes an interchangeable battery pack (2). The battery pack is fitted to the main unit (1) of the device. An auxiliary functional unit (AFU) (10) is contained within the battery pack (2). It communicates data bidirectionally with circuits within the main unit (1) of the device. The auxiliary functional unit thereby performs an auxiliary function in conjunction with the circuits in the main unit of the device. The auxiliary functional unit may be a pager and the main unit may be a cellular telephone. Then in a standby mode the phone circuits are switched off and the pager only left powered-up.

Description

BATTERY POWERED DEVICE

BACKGROUND TO THE INVENTION

The present invention relates to a battery powered electronic device and particularly, but not exclusively, to battery-powered cellular telephones, and methods of operating cellular telephones and cellular telephone networks.

In designing consumer electronics products - such as cellular telephones, other communications or data processing equipment or audio-visual equipment such as camcorders - there is a general need to provide improved performance and additional operational features so as to enhance the attractiveness of the product to the consumer. On the other hand, for each such product there is usually a sector of the market which is extremely price sensitive. For this part of the market there is a need to strip out all but the most essential features in order to minimize the price. These conflicting needs can be met by providing different designs for the different market sectors, but then there is a loss of the economies of scale which might otherwise be obtained.

Another important design factor in the manufacture of battery-powered products is the need to maximise battery life. Particularly in relation to cellular telephones, the maximum standby time, that is the time for which the telephone can be left not in active communication but in readiness to receive a call, is an important performance parameter. It is, for example, one of the most frequently quoted parameters in comparative reviews of such phones. Despite the practical and commercial importance of this parameter, it has not hitherto proved possible to extend the standby time for a typical ETACS phone much beyond 24 hours using a 600 mAHr battery.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a battery-powered portable electronic device including an interchangeable battery pack fitted to a main unit of the device, characterised by an auxiliary functional unit contained within the battery pack and arranged to communicate data bidirectionally with circuits within the main unit of the device, the auxiliary functional unit thereby performing the auxiliary function in conjunction with the said circuits within the main unit of the device.

By an auxiliary function is meant a function which adds to or enhances the primary functioning of the device and not merely charge management or other functions of the type conventionally associated with battery packs.

This aspect of the present invention takes advantage of the fact that the battery-powered electronic device necessarily has at least one interchangeable module and associated interface, namely that of the battery pack itself. By providing auxiliary functional units which fit within the battery pack, and using the enhanced battery pack interface, the invention makes it possible for the same basic unit to provide different levels of function for different sectors of the market, while maintaining maximum economies of scale. All this is achieved without adding significantly to the size, complexity or cost of the base-level model, since no additional interface is required.

In the case of a cellular telephone, the auxiliary functional unit might comprise, for example, an answering machine, a silent vibrating alarm, a cordless phone or a pager as discussed below in relation to the other aspects of the invention. The unit may provide two or more such functions in combination, for example both an answering machine and a pager.

Preferably the main unit of the device includes a user input device and is arranged to communicate control signals to the auxiliary functional unit in response to a user input. The user input device might be, for example, the keypad of a cellular telephone and may be used to program and control the auxiliary functional unit via the battery pack interface.

Preferably the interface for the battery pack includes a connection for the transmission of power from the main unit to the auxiliary functional unit.

Although the auxiliary unit is located adjacent the battery power supply, it is found to be advantageous for many purposes if it is not directly connected to the batteries, but receives its power via the main unit. This reduces the need for power switching or control circuitry within the auxiliary unit. This aspect of the invention also encompasses a battery pack incorporating an auxiliary functional unit.

According to a second aspect of the present invention, there is provided a cellular telephone, characterised by a pager module powered independently of the primary telephony circuits of the telephone and arranged to power-up the said telephony circuits when a paging signal is received.

This aspect of the invention takes a novel approach to the problem of extending the standby time of a cellular telephone. Instead of attempting to enhance the batteries or to reduce the power drain of the telephony circuits, the present inventors have added to the telephone a pager module able to "wake-up" the phone on receipt of a pager signal. This allows the main circuits to be turned OFF and so reduces the battery drain from the 20 to 40 mA conventionally associated with standby mode to a much lower level, typically around 0.1 - 0.4 mA, associated with the drain current of the pager in standby. By using the pager to provide the standby function, the inventors have been able to extend the standby lifetime of the phone from around 24 hours to as long as 3 weeks, thereby doing away with the need for daily recharging of the batteries.

Preferably the pager module is arranged to communicate caller line identification (CLI) data to the primary telephony circuits.

Preferably the primary telephony circuits are arranged to display to the user the CLI data received from the pager module.

Preferably the primary telephony circuits are arranged to make a registration with the cellular network automatically after powering-up in response to a paging signal.

It is found to be particularly advantageous to have the pager use CLI data to ready the telephone to make a return call to the caller at the press of a button, should the user wish to do so.

The pager is preferably fitted within a battery pack, in accordance with the first aspect of the invention. In this case, preferably the pager is arranged to communicate data bidirectionally with the primary telephony circuits via the connection between the battery pack and the main unit of the telephone. The phone may be arranged so that the user can choose between one mode in which, after the completion of the call, the primary telephony circuits are powered down again, or a second and alternative mode, in which at the completion of the call the telephony circuits remain powered, giving the user the option of making a further call.

According to a third aspect of the present invention, there is provided a method of operating a cellular telephone including placing the telephone in a standby mode to reduce power consumption, characterised in that in standby mode power to the primary telephony circuits is turned OFF and power to a pager module remains ON, and in that the pager module, on subsequently receiving a pager signal, switches ON power to the primary telephony circuits.

Optionally, at the end of the conversation upon detection of mobile/network release, cellular phone primary circuit power may be switched OFF, and power to the pager remains ON, ready for the next incoming call.

According to a fourth aspect of the present invention, there is provided a method of operating a cellular telecommunications network characterised by transmitting a pager signal from the network to a cellular telephone, receiving the pager signal in a pager module in the cellular telephone while the primary telephony circuits of the cellular telephone are powered-down, switching ON power to the primary telephony circuits in response to the pager signal, and subsequently establishing a connection between the said primary telephony circuits and the network.

Preferably the method further comprises receiving at the network exchange a destination telephone number from a call originator; and

only when the destination cellular telephone is determined to be not registered, then outputting from the network exchange a pager signal, and otherwise establishing a connection directly with the primary telephony circuits of the destination cellular telephone.

Preferably the network exchange stores a record of destination numbers and corresponding pager numbers, and when the destination cellular telephone is determined to be not registered then retrieves the corresponding pager number for use in signalling the pager module. The present invention's approach to extending cellphone standby time can be implemented simply using existing telephone and pager networks. This however requires the caller to have both the telephone number and pager number of the destination. This can be avoided, and the invention implemented in a manner transparent to the user, if the network exchange logs when a given phone is not registered, and then retrieves and uses the corresponding pager number from a database to transmit it on the pager network thereby switching ON the phone and enabling a connection to be made. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention in its different aspects will now be described in further detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a block diagram which shows schematically a device embodying the present invention;

Figures 2A and 2B are a front elevation and side elevation respectively of the device of Figure 1;

Figure 3 is a sectional view of a battery pack incorporating a pager;

Figure 4 is a sectional view of a battery pack including an answering machine;

Figures 5A and 5B are block diagrams for the pager of Figure 3 and 5C shows the interface for the pager or other AFU;

Figure 6 is a diagram illustrating a first method of operation for a network; and

Figure 7 is a diagram for a second method of operation for a network.

DESCRIPTION OF EXAMPLES

A battery-powered portable electronic device, in the present example a hand-held cellular telephone or "handphone" 1 includes an interchangeable battery pack 2, which is fitted to the main body of the handphone 1 and is electrically connected to the handphone 1 via an interface 3. The handphone 1 includes a power management circuit 4, a control microprocessor 5 and telephony transmission/ reception circuits 6. A key pad 7 acts as a user input device, serving both the dialling of numbers, and also for programming of the different functions of the handphone 1. The number dialled, and other indications relating to the functioning of the phone are displayed on an LCD 8. These primary circuits within the handphone 1 are all conventional in construction, and so will not be described in further detail here.

Figures 2A and 2B show the external features of the handphone 1 and battery pack with AFU 2. As is conventional with handphone battery packs, the battery pack when fitted to the phone is normally held rigidly to the body of the device with a connection established to the circuits of the handphone 1 using a pin and contact arrangement. However, the pack may be released when, for example, it is decided to recharge the batteries.

In the present example the handphone uses a transmit frequency band from 872 MHz to 905 MHz and a receive frequency band from 917 MHz to 950 MHz. It operates in power class 4 with duplex spacing of 45 MHz and channel spacing of 25 KHz. The phone can access 1320 channels. It communicates using FM modulation with FSK Manchester coding. In this example, the phone has physical dimensions of 149 × 55 × 26.5 mm. It includes a 2 × 12 dot-matrix supertwist LCD with back lighting.

For conventional operation, in which the battery packs serves only to provide power to the handphone 1, then the pack may contain conventional AA (NiCd) batteries. Alternatively, as in the example illustrated, prismatic NiMH or NiCd batteries may be used. In this case, the battery pack holds in addition to the batteries an auxiliary functional unit (AFU) 10.

The batteries 9 supply power to the handphone 1 via the interface 3. The

AFU 10 receives power from the handphone 1 via the interface and communicates data bidirectionally with the handphone 1 via the interface. It may be programmed and controlled via the keypad 7 and microprocessor 5 in the handphone 1. In a first example illustrated in further detail in Figures 3 and 5 A to 5C, the AFU is a pager. As will be described in further detail below, this functions in combination with the circuits in the handphone 1 to extend greatly the standby time of the handphone. As seen in Figure 3, the casework for the battery pack 2 is divided at approximately half its height by an internal wall 31. A PCB 32 mounted on one side of the dividing wall 31 provides the circuits of the pager. Four prismatic batteries 33a to d are contained in the pack below the dividing wall 31 and are electrically connected to the pack output pins 34 via contact pads 35. The pack includes a thermistor 36 (SEMITEC 103 AT-2) and a poly-switch 37 (RAYCHEM SRP200). These both serve as safety devices to protect against overheating of the pack when charging. A ferrite antenna 38 mounted directly on the PCB picks up the paging signal transmitted by the paging network to the pager.

The output pins from me pack 34 are shown in further detail in Figure 3. It comprises 10 pin contacts having a pitch of 2.54 mm. The battery ground and battery positive contacts are located at the extreme ends. This is found to give better electrical performance. The pin labelled Pwr-to-Acc provides a power input signal to the accessory pack. The AFU electronics therefore only get the power when the pack is mounted on the main electronics. This therefore provides an interlock mechanism for the powering-up of the AFU. Select line 1 and 2 are logic inputs to the main electronics indicating the type of AFU being operated. The transmit data and receive data pins communicate signals carrying proprietary protocol information between the main electronics and the AFU electronics and provide data transactions in respect of the pager, answering machine or other AFU.

The interface between the battery pack including the AFU and the main electronics, i.e. the main circuits of the handphone in the present example, uses a proprietary serial protocol designed to provide maximum flexibility and ease of communication. It has two basic data formats. One to carry messages from main electronics to enhancement (i.e. AFU) electronics, the other in the reverse direction. The protocol defines message type fields, device identification code fields, and longitudinal redundancy check (LRC) fields, in addition to data fields. It provides a mechanism for acknowledgement of data transactions between the main electronics and the enhancement (AFU) electronics.

In a second example shown in Figure 4, the AFU 10 contained within the battery pack 2 is an answering machine. As in the previous example, the electronics for the answering machine are provided as a PCB 42 mounted on a dividing wall 41 of the battery pack, as shown in Figure 4.

A variety of other options are possible for the AFU. For example, it may comprise a silent vibrating alarm to be used when desired in place of the usual audio ringing tone of the handphone 1. The operation of the answering machine is described in further detail below.

CORDLESS PHONE

A further option is that the AFU may enable the handphone to function as a cordless phone. In this case the AFU contains circuits for providing a relatively low power radio frequency link between the phone and a cordless phone base unit connected to a telephone line. The AFU the allows the AF circuits of the handphone to be used in making a conventional telephone call via the telephone line. While in use in this manner the handphone is not in registered with the cellular network and does not incur charges from that network.

ANSWERING MACHINE

The answering machine is described in detail in Annex B. It includes a Solid State memory for recording messages and includes an option for recording an ongoing conversation between the handphone user and a called or calling party.

SERIAL BUS PROTOCOL

The serial bus provides means to establish point-to-point communication between the Handset and the Auxiliary Functional Unit (AFU). There are three types of messages transacted:

- Command messages

- Respond messages

- Status Messages

Either device i.e. the Handset or AFU may issue and respond to a set of commands. All messages are binary based (with the exception of monitor status where its data is ASCII-based for ease of monitoring). All messages are single word.

Command Messages: At the link level each command message will be ACKed or NACKed by the receiving party according to the reception of the message. For some commands, the requested operation of the command will be responded by a separate response message.

The following is the list of commands that are applicable to the AFU providing a functionality of either a Pager or an Answering Machine.

In response to the command set the AFU reply with appropriate response along with its Device Identification Codes (DIC). Status messages from the AFU indicate certain conditions are satisfied, hence action can be originated by the main unit. For Pager AFU these are:

EXTENDING STANDBY TIME

The use of a pager in combination with a handphone to extend the standby time of the handphone will now be described in further detail. The pager is preferably, but not necessarily, provided as an AFU within a battery pack, as described above.

Four modes of operation may be defined for a cellular phone:

(A) Full-OFF, battery not attached. In this state there is zero current drain from the battery. The phone cannot originate a call, and cannot terminate a call.

(B) Battery attached, "Pagullar" standby. In this state there is a small current drain and current going to the pager. The phone is in OFF state. Only the wake-up circuits in the phone are powered to detect ON/OFF key press, or wake-up signals from the pager module.

(C) Switched on, conventional standby mode. Here the cellular phone is not in an act of conversation with the base station but is "registered" and ready to receive a call from the cellular base station. The battery drain is significant, in the range 20 - 50 mA.

(D) Switched on, call in progress mode. Here the cellular phone is in active communication with a cellular base station. The battery drain in this mode is very high, typically 500 to 700 mA. Modes A, C and D are conventional. Mode B is provided by phones embodying the present invention, and provides an alternative standby mode, termed by the inventors "Pagullar standby" which enables a greatly increased standby time. The battery standby time is the time duration in which the cellular phone can be in standby mode with a fully charged battery of pre-defined capacity measured in mAHr. As already discussed, typically for ETACS type handphones, a standby time of about 24 hours is achievable. In this example of the present invention, the standby time is greatly extended through the use of a pager incorporated in the handphone. The pager is connected to the circuits of the handphone by an interface of the type described above and is independently powered from the batteries via the handphone. When in "Pagullar standby" mode the main circuits of the handphone are switched off. The pager however remains in a standby state in which it has a small current drain of around 0.1 - 0.4 mA. When a call is to be made to the switched-off handphone, then a paging signal is sent to the pager which in turn transmits a control signal via the interface to the handphone to turn the handphone ON. Two scenarios for making or terminating a call will now be described by way of example.

Scenario A: This is a simple solution which can be implemented immediately using existing networks and without requiring co-operation between the pager and mobile phone networks. Following this scenario, the call originator uses the pager number to make a page to the pager options pack indicating that he wants to make contact with the cellular phone. On receipt of a paging signal, the caller's number is captured by the pager using caller line identification CLI. The pager then transmits a control signal to wake-up the phone and communicates the CLI information to the cellular phone via the interface. The caller's number is displayed on the handphone display automatically. Simultaneously, the handphone makes registration with the cellular network. Should the handphone user choose to return the call, then he or she presses the SEND key, the cellular phone dials the CLI number, and hence is able to return the calling party's telephone call. This approach has the advantage of not requiring any modification to existing network. However it does require the caller to know both the telephone number and the pager number of the destination. On return of the call, the cellular phone is the initiator of the call and hence has to pay that portion of the cost for the call.

Scenario B: This uses a modified mode of operation for the networks to make the process more friendly to the user. It is however more complex to implement. It requires the co-operation of the cellular and pager network operators to include intelligence in the network management software. Following this scenario, the call originator makes a call to the cellular phone number. The cellular phone network knows that the phone is switched off and hence not registered. The cellular network then looks up in a database the equivalent pager number matched to the cellular phone number. Transparently to the calling party, the cellular phone network initiates a paging call through the paging network to wake-up the cellular phone, awaits registration, and completes the call when the freshly awoken cellular phone is registered with the network.

In this way, the caller does not need to know if the cellular phone is switched on, or if it has a pager option. The caller makes a "normal" call and the method of operation is transparent both to the caller and the called party. The cellular phone and the pager network do the signalling automatically. While the operation of the phone appears conventional to the user, the ability to switch off the main circuits and leave just the pager in standby reduces a greatly increased standby time which may be as long as 3 weeks.

Figure 6 illustrates scenario A discussed above, and Figure 7 scenario B. In the following appendices, Appendix A describes in further detail the plug- in pager module, Appendix B describes the plug-in answering machine and Appendix C describes the proprietary serial data protocol.

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Claims

1. A battery-powered portable electronic device (1) including an interchangeable battery pack (2) fitted to a main unit of the device, characterised by an auxiliary functional unit (AFU) (10) contained within the battery pack and arranged to communicate data bidirectionally with circuits within the main unit of the device, the auxiliary functional unit (10) thereby performing the auxiliary function in conjunction with the said circuits within the main unit (1) of the device.

2. A device according to claim 1 in which the physical interface (3) between the battery pack (2) and the main unit (1) comprises a multiplicity of contact pins arranged in a linear array with a battery ground contact pin at one end of the array, a battery +ve contact pin at the other end of the array, and at least one data pin between the said battery contact pins and connected to the auxiliary functional unit.

3. A device according to claim 2 in which the interface (3) includes 2 data pins, one carrying data unidirectionally from the AFU to the main unit, and the other carrying data unidirectionally from the main unit to the AFU.

4. A device according to claim 1, 2 or 3 in which the main unit of the device includes a user input device (7) and is arranged to communicate control signals to the auxiliary functional unit (10) in response to a user input.

5. A device according to any one of the preceding claims in which the interface (3) for the battery pack includes a connection for the transmission of power from the main unit to the auxiliary functional unit (10).

6. A device according to any one of the preceding claims, in which in a standby mode of the device only the auxiliary functional unit (10) is powered, and the auxiliary functional unit is arranged subsequently to switch ON power to the main unit.

7. A device according to claim 6, in which the auxiliary functional umt (10) switches ON the main unit in response to a signal received from a source external to the device.

8. A device according to any one of the preceding claims, in which the device (1) is a cellular telephone.

9. A device according to claim 8, in which the auxiliary functional unit (10) is a pager.

10. A device according to claim 8, in which the auxiliary functional unit (10) is an answering machine.

11. A device according to claim 8, in which the auxiliary functional unit (10) is a vibrating silent alarm.

12. A device according to claim 8, in which the auxiliary functional unit (10) is a cordless phone.

13. An interchangeable battery pack (2) arranged to be fitted to the main unit of a portable electronic device, characterised by an auxiliary functional unit (10) contained within the battery pack and arranged to communicate data bidirectionally with circuits within the main unit of the device, the auxiliary functional unit thereby performing the auxiliary function in conjunction with the said circuits within the main unit of the device

14. A cellular telephone, characterised by a pager module powered independently of the primary telephony circuits of the telephone and arranged to wake-up the said telephony circuits when a paging signal is received.

15. A cellular telephone according to claim 14, in which the pager module is arranged to communicate caller line identification (CLI) data to the primary telephony circuits.

16. A cellular telephone according to claim 15, in which the primary telephony circuits are arranged to display to the user the CLI data received from the pager module.

17. A cellular telephone according to any one of claims 14 to 16 in which the primary telephony circuits are arranged to make a registration with the cellular network automatically after powering-up in response to a paging signal.

18. A cellular telephone according to any one of the preceding claims, in which the pager is contained in an interchangeable battery pack fitted to the phone.

19. A cellular telephone according to any one of the preceding claims, in which the pager is arranged to communicate data bidirectionally with the primary telephony circuits via the connection between the battery pack and the main unit of the telephone.

20. A method of operating a cellular telephone including placing the telephone in a standby mode to reduce power consumption, characterised in that in standby mode power to the primary telephony circuits is turned OFF and power to a pager module remains ON, and in that the pager module, on subsequently receiving a pager signal, switches ON power to the primary telephony circuits.

21. A method according to claim 20, in which the pager module receives caller line identification (CLI) data and communicates the said CLI data to the primary telephony circuits.

22. A method according to claim 21, in which the primary telephony circuits display the CLI data received from the pager module.

23. A method according to any one of claims 20 to 22, in which the telephony circuits make a registration with the cellular network automatically after waking-up in response to a paging signal.

24. A method of operating a cellular telecommunications network characterised by transmitting a pager signal from the network to a cellular telephone, receiving the pager signal in a pager module in the cellular telephone while the primary telephony circuits of the cellular telephone are powered-down, switching ON power to the primary telephony circuits in response to the pager signal, and subsequently establishing a connection between the said primary telephony circuits and the network.

25. A method according to claim 24, further comprising:

receiving at the cellular network exchange a destination cellular telephone number from a call originator; and

only when the destination cellular telephone is determined not to be registered with the cellular network then outputting from the network exchange a pager signal, and otherwise establishing a connection directly with the primary telephony circuits of the destination cellular telephone.

26. A method according to claim 25, in which the network exchange stores a record of destination numbers and corresponding pager numbers, and when the destination cellular telephone is determined to be not registered powered-down then retrieves the corresponding pager number for use in signalling the pager module.