Apparatus for sensing the presence of a mobile telephone in its holder

• US 6,236,868 B1
• Filed: 05/29/1998
• Issued: 05/22/2001
• Est. Priority Date: 05/29/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Lygas, Edward A.
• Primary Examiner(s): Trost, William G.
• Application Number:
  US09/086,972
• Time in Patent Office: 1,089 Days
• Field of Search: 455/550, 455/569, 455/572-573, 455/575, 455/90, 455/347-351, 455/41, 379/428, 379/433, 379/429, 379/432, 248/309.4, 248/671, 248/683, 324/207.11, 324/207.13, 324/207.15, 324/207.2, 324/207.22, 324/219, 324/260-61
• US Class Current: 455/569.2
• CPC Class Codes: H04B 1/3877 Arrangements for enabling portable transceivers to be used in a fixed position, e.g. cradles or boosters
• CPC Class Codes: H04M 1/6075 adapted for handsfree use in a vehicle H04M1/6058 takes precedence; arrangements for holding telephones in a vehicle B60R11/0241

Abstract

A apparatus for sensing the presence of a mobile telephone within a holder for the telephone. A winding is located within either the telephone, the telephone'"'"'s battery pack or a plug connected to the telephone. A magnetic element is disposed within a portion of the holder that is proximate to the winding when the telephone is present within the holder. Detection circuitry is coupled to the winding and detects, based on current flow through the winding, if the winding is in proximity to the magnetic element, which indicates that the telephone is present within the holder. The system may automatically enter a hands-free mode whenever the presence of the telephone within the holder is sensed. The magnetic element may be a transformer secondary to enable power to be delivered to other electronics within the holder, such as a light emitting element, whenever the telephone is present therein.

Claims

1. An apparatus for sensing the presence of a mobile telephone within a holder for said telephone, comprising:

a winding located within one of said telephone, a battery pack of said telephone, and a plug connected to said telephone;

a magnetic element disposed within a portion of said holder that is proximate to said winding when said telephone is present within said holder; and

detection circuitry coupled to said winding for detecting, based on current flow through said winding, if said winding is in proximity to said magnetic element which indicates that said telephone is present within said holder;

wherein said detection circuitry comprises;

a resistive-capacitive (RC) circuit, including a current sense resistor coupled to said winding; and

switching circuitry for switchably coupling a source of potential to said RC circuit so as to generate an AC current through said winding, with frequency of said AC current being detected and determinative of whether the telephone is present within the holder.

2. The apparatus of claim 1 wherein said winding is located within said plug.

3. The apparatus of claim 1 wherein said winding is located within said telephone.

4. The apparatus of claim 1 wherein said winding is located within a removable battery pack of said telephone.

5. The apparatus of claim 1 wherein said magnetic element comprises ferromagnetic material.

6. The apparatus of claim 1 wherein:

said winding is wrapped around a magnetic core to form a transformer primary;

said magnetic element comprises a transformer secondary; and

said holder includes electronics that are activated by power induced in said secondary by magnetic coupling from said primary when said telephone is present within said holder.

9. The apparatus of claim 1 wherein said switching circuitry comprises a pair of switches, and said apparatus further comprises a control circuit which causes said pair of switches to switch on and off in a complementary manner.

10. The apparatus of claim 9, further comprising window comparator electronics coupled across said sense resistor for sensing AC current flow through said resistor and providing a logic output signal of a first level when said AC current exceeds a first threshold and of a different logic level when said AC current falls below a second threshold;

and a control circuit for monitoring the logic output of said window comparator and based thereon, determining whether said telephone is present within said holder.

11. The apparatus of claim 10 wherein said switches are switched in accordance with the output signal of said window comparator so as to maintain said AC current at a substantially constant amplitude.

12. The apparatus of claim 1, further comprising a cable connected to said plug and a base unit coupled to said telephone via said cable, said base unit housing said detection circuitry.

13. The apparatus of claim 1, further comprising speakerphone electronics to permit hands-free operation of said telephone, said speakerphone electronics being automatically activated in response to a signal from said detection circuitry indicating that said telephone is present within said holder.

7. An apparatus for sensing the presence of a mobile telephone within a holder for said telephone, comprising:

a primary winding located within one of said telephone, a battery pack of said telephone, and a plug connected to said telephone;

a secondary winding disposed within a portion of said holder that is proximate to said primary winding when said telephone is present within said holder; and

detection circuitry coupled to said primary winding for detecting, based on current flow through said primary winding, if said primary winding is in proximity to said secondary winding which indicates that said telephone is present within said holder;

wherein said holder includes electronics that are activated by power induced in said secondary winding by magnetic coupling from said primary winding when said telephone is present within said holder, said activated electronics including a light emitting element that illuminates said holder when said telephone is placed therein.

8. The apparatus of claim 7 wherein said electronics include an electronic dialer integrated with said holder.

14. An apparatus for sensing the presence, within a holder, of an electronic device removable from said holder, comprising:

a primary winding located within a plug connected to said electronic device;

a secondary winding disposed within a portion of said holder that is proximate to said electronic device when said electronic device is present within said holder;

detection circuitry coupled to said primary winding for detecting, based on current flow through said primary winding, if said primary winding is in proximity to said secondary winding which indicates said electronic device is present within said holder; and

said holder includes a light emitting element that is activated by power induced in said secondary winding when the electronic device is placed within the holder.

15. The apparatus of claim 14 wherein said primary and secondary windings are each wrapped around a magnetic core.

16. The apparatus of claim 15 wherein said detection circuitry comprises:

a resistive-capacitive (RC) circuit coupled to said primary winding;

a source of potential switchably coupled to said RC circuit via a pair of switches so as to generate an AC current through said primary winding, with frequency of said AC current being detected and determinative of the presence of the electronic device within the holder.

17. The apparatus of claim 16, further comprising a control circuit for controlling switching of said switches, and said apparatus further includes means for current-limiting said AC current such that said AC current is of a substantially constant amplitude.

18. A holder for a mobile telephone comprising:

a housing;

a transformer secondary disposed within said housing; and

,

a load coupled to said secondary, said load receiving driving power from a transformer primary associated with said telephone through said secondary via magnetic coupling when said telephone is present within said holder;

wherein said transformer primary exhibits an impedance; and

said load includes means for changing the impedance of said transformer primary by altering the load conditions on said secondary to provide digital signaling from said holder that is monitorable by sensing changes in current supplied to said transformer primary.

19. The holder of claim 18 wherein said means for changing the impedance comprises coupling means for coupling said secondary to a reference potential and means for varying the impedance of said coupling means.

20. The holder of claim 19 wherein said coupling means is a resistor and said means for varying the impedance of said coupling means is a switch connected in parallel with said resistor.

21. Mobile telephone apparatus comprising:

a base unit for supplying power;

a mobile telephone unit connected to said base unit for receiving current from said base unit, said mobile telephone unit including a transformer primary to which said current is supplied, said transformer primary exhibiting an impedance;

a holder for said mobile telephone unit and including a transformer secondary magnetically coupled to said transformer primary;

a load coupled to said transformer secondary, said load receiving driving power from said transformer primary through said transformer secondary and including means for changing the impedance of said transformer primary by altering the load conditions on said transformer secondary to thereby vary the current supplied to said transformer primary and provide digital signaling from said holder via said mobile telephone unit to said base unit as a function of the varied current.

22. An apparatus for sensing the presence of a mobile telephone within a holder for said telephone, comprising:

a winding located within a plug connected to said mobile telephone;

a magnetic element disposed within a portion of said holder that is proximate to said winding when said telephone is present within said holder; and

detection circuitry coupled to said winding for detecting, based on current flow through said winding, if said winding is in proximity to said magnetic element which indicates that said telephone is present within said holder.

23. The apparatus of claim 22 wherein said plug is integrated with a cable connecting said mobile telephone to a base unit containing said detection circuitry.

24. The apparatus of claim 22 wherein said plug consisting essentially of:

said winding;

wires that connect said winding to a base unit containing said detection circuitry; and

a connector portion electrically connecting said mobile telephone to said base unit.