GB2336953A

GB2336953A - Deriving power for an electronic apparatus which can be coupled to an electronic unit

Info

Publication number: GB2336953A
Application number: GB9805647A
Authority: GB
Inventors: Efraim Rushinek; Reuven Konevky; Simha Tanne
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1998-03-18
Filing date: 1998-03-18
Publication date: 1999-11-03
Anticipated expiration: 2018-03-18
Also published as: GB2336953B; GB9805647D0

Abstract

A GSM data unit 100 can be coupled with a palm-top computer 108 (or a PDA or laptop PC) which has its own power source. The data unit 100 has a battery 112 which can be connected by a switch 110 to an internal power supply line 116 for powering RF unit 102, base band unit 104 and modem 106 (eg. a PCMCIA circuit). On initially coupling the data unit 100 to the computer 108, a changeover switch 124 is in a position connecting low power circuitry within a controller 122 of modem 106 for powering from the power source within computer 108 via an interfacing terminal 128. On sensing the presence of voltage on supply line 126 from computer 108, modem controller 122 tests units 102 and 104. If the units 102, 104 are functioning correctly, the controller 122 closes the power switch 110 and switches the switch 124 to the power line 116 so that the battery 112 is used to supply power to the GSM data unit 100 instead of the source in computer 108. In response to a power down instruction, or in response to the GSM data unit 100 being unplugged from computer 108, a call processor 120 in unit 104 opens switch 110 to prevent further drain from battery 112, and the changeover switch 124 returns to the state in which interfacing terminal 128 is coupled to modem controller 122.

Description

2336953 ELECTRONIC APPARATUS FOR COUPLING WITH AN ELECTRONIC UNIT AND

METHOD OF DERIVING POWER THEREFOR

Field of the Invention

The present invention relates to an electronic apparatus for coupling with an electronic unit and method of deriving power therefor. An example of the electronic apparatus is a combined radio communi cations module and modem, such as a Global System for Mobile Communication (GSM) circuit combined with a PCMCIA data card.

Background of the Invention

It is known to electrically connect a combined radio-communications/modem card (hereinafter "the GSM data unit") to another electronic device7 such as a palm-top computer, PDA or a Laptop Personal Computer (PC). As would be expected, it is necessary to provide power for the electronic circuitry of the GSM data unit. However, it is disadvantageous to derive the power needed to power the GSM data unit from the palm-top computer, as this will reduce the amount of time that the palm-top computer can remain operational. A solution is therefore to provide the GSM data unit with a separate dedicated power source, for example, a battery. The separate power source will have to be connected in-circuit by means of a switch. However, the provision of a physical switch is undesirable, because it is possible that a user may forget to switch off the GSM data unit when use of it is no longer needed. If an electronic switch is to be employed to control the provision of power to the card unit from the separate battery, the problem remains as to how to connect the battery in-circuit on imitially.

It is thus an object of the present invention to obviate or at least mitigate the above mentioned problem associated with GSM data units or other electronic devices having a built-in power source.

1 SummaW-of the Invention According to the present invention, there is provided an electronic apparatus for coupling with an electronic unit having a first power source, the apparatus having electronic circuitry selectively coupled to a second power source by a switch, wherein the electronic circuitry is arranged to derive at least sufficient power initially from the first power source of the electronic unit to enable the electronic circuitry to subsequently actuate the switch, and thereby derive power from the second power source thereafter.

It is thus possible to activate the switch using minimal power from the first power source.

According to the present invention, there is also provided a method of deriving power for an electronic apparatus to be coupled with an electronic unit having a first power source, the electronic apparatus being selectively coupled to a second power source by a switch, the method comprising the steps of. deriving at least sufficient power initially from the first power source of the electronic unit to enable the electronic circuitry to subsequently actuate the switch, deriving power, in response to the actuation of the switch, from the second power source thereafter.

Other, preferred, features and advantages are set forth, and will become apparent from, the appended dependent claims, description and drawings.

Brief Description of thp, Drawings

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an apparatus constituting an embodiment of the present invention, and FIG. 2. is a flow diagram of method for use with the apparatus of FIG. 1.

Description of a Preferred Embodiment

A combined radio-communications and modem unit, for example, a GSM data unit 100 comprises a Radio Frequency (RF) unit 102, a Base Band (BB) unit 104 and a modem unit 106, for example, a PCMCIA circuit. The GSM data unit 100 is capable of interfacing with an electronic device, preferably but not limited to, a portable electronic device, for example a palm-top computer, PDA or a Laptop PC 108.

For the purposes of clarity and simplicity of description, the circuitry of the GSM data unit 100 will not be described in detail. Furthermore, the detailed construction and operation of the GSM data unit 100 does not relate to essence of the present invention.

The RF unit 102 has a first switch 110, having a first terminal coupled to a first terminal of a battery 112, the second terminal of the battery 112 being connected to ground 114. The second terminal of the first switch 110 is coupled to an internal power supply line 116 for supplying electrical power from the battery 112 to the RF unit 102, the BB unit 104 and the modem 20 unit 106.

The first switch 110 is coupled to a first control line 118 which is coupled to a call-control processor 120 located within the BB unit 104. The first control line 118 is also coupled to modem controller 122 located within the modem unit 106 having a low current circuit (not shown).

The modem controller 122 is also coupled to a first terminal of a second switch 124, preferably a three-way switch in order to supply power to the modem controller 122. A second terminal of the second switch 124 is connected to the internal power supply line 116, the third terminal of the second switch 124 being connected to an incoming power line 126 having an interfacing terminal 128. The second switch 124 is controlled by the modem controller 122 via a second control line 130 coupled to the modem controller 122. The second switch 124 is capable of switching between a first position, in which the modem controller 122 is connected to the incoming power supply line 126, and a second position, in which the modem controller 122 is connected to the internal power supply line 116.

The palm-top computer 108 is capable of being interfaced with the GSM data unit 100, in particular at the interfacing terminal 128, through which power can be supplied from a power source within the palm-top computer 108. Other interface connections can be provided, for example, for the purpose of communication between the GSM data unit 100 and the palm-top computer 108.

The operation of the above described embodiment will now be described with reference to FIG. 2.

Initially, the second switch 124 is arranged to couple the interfacing terminal 128 to the modem controller 122. Upon connection of the GSM data unit 100 to the palm-top computer 108, the modem controller 122 detects the connection by sensing a voltage at the interfacing terminal 128 (step 200).

The power supply within the palm-top computer 108 is used to power the low current circuit within the modem controller 122 (step 202). The modem controller 122 then tests the BB unit 104 and the RF unit 102 to ensure that they are functioning correctly (step 204). If the BB unit 104 and the RF unit 102 are not functioning correctly, the GSM data unit 100 does not proceed and generates an error message (not shown) in accordance with any technique known in the art. However, if the test does not reveal any problems with the BB unit 104 and the RF unit 102, the modem controller 122 actuates the first switch 110 by means of the first control line 118 (step 206) and actuates the second switch 124 by means of the second control line (step 208). The battery 112 is thereby used to supply power to the GSM data unit 100 instead of the power supply of the PC 108 via the interfacing terminal 128.

The GSM data unit 100 then continues to operate as normal until the GSM data unit 100 is either unplugged from the palm-top computer 108 or receives an instruction to power-down (step 210). If the GSM data unit 100 is either unplugged or receives an instruction to power-down, the call controller 120 actuates the first switch 110 so as to prevent power being supplied from the battery 112 and the second switch 124 returns to a state where the interfacing terminal 128 is coupled to the modem controller 122.

The first and second switches 110, 124 are preferably electronic switches, for 5 example, transistors. However, the use other switches is envisaged, such as opto-isolators.

Although the invention has been described in the context of a GSM data unit 100 and a palm-top computer 108, it should be appreciated that the present invention is not limited to such a configuration and is also applicable to any first electronic device having a power supply, the first electronic device being capable of being coupled to a second electronic device having a second power supply, and where the prolonged use of the second power supply is undesirable.

Claims

1. An electronic apparatus for coupling with an electronic unit having a first power source, the apparatus having electronic circuitry selectively coupled to a second power source by a switch, wherein the electronic circuitry is arranged to derive at least sufficient power initially from the first power source of the electronic unit to enable the electronic circuitry to subsequently actuate the switch, and thereby derive power from the second power source thereafter.

2. An apparatus as claimed in Claim 1, wherein the electronic circuit is a low-current circuit.

3. An apparatus as claimed in Claim 1 or Claim 2, wherein the first 15 power source is a battery.

4. An apparatus as claimed in any in of the preceding claims, wherein the second power source is a battery.

5. An apparatus as claimed in any in of the preceding claims, wherein the electronic circuitry includes an RF portion and a Baseband portion.

6. An apparatus as claimed in any in of the preceding claims, wherein the switch is actuated by means of at least one processor.

7. An apparatus as claimed in any in of the preceding claims, wherein the electronic circuitry is arranged to actuate the switch in order to prevent derivation of power from the second power source in response to the apparatus being decoupled from the electronic unit.

8. An apparatus as claimed in any in of Claims 1 to 6, wherein the electronic circuitry is arranged to actuate the switch in order to prevent derivation of power from the second power source in response to the apparatus being instructed to power-down.

9. A combined radio-communi cations and modem apparatus as claimed in any one of Claims 1 to 8.

10. A method of deriving power for an electronic apparatus to be coupled with an electronic unit having a first power source, the electronic apparatus being selectively coupled to a second power source by a switch, the method comprising the steps of. deriving at least sufficient power initially from the first power source of the electronic unit to enable the electronic circuitry to subsequently actuate the switch, deriving power, in response to the actuation of the switch, from the second power source thereafter.

11. An electronic apparatus substantially as hereinbefore described with reference to FIG. 1.

12. A method of deriving power substantially as hereinbefore described with reference to FIG. 2.