Electronically controlled timepiece, and power supply control method and time correction method therefor

• US 6,757,220 B1
• Filed: 07/28/2000
• Issued: 06/29/2004
• Est. Priority Date: 09/22/1998
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nakamura, Hidenori, Shimizu, Eisaku, Koike, Kunio
• Primary Examiner(s): Miska, Vit
• Assistant Examiner(s): GOODWIN, JEANNE M
• Application Number:
  US09/554,963
• Time in Patent Office: 1,432 Days
• Field of Search: 368/203, 368/204
• US Class Current: 368/204
• CPC Class Codes: G04C 10/00 Arrangements of electric power supplies in time pieces circuits G04G19/00; mounting, assembling of components of electromechanical watches G04C3/008, of electronic watches G04G17/00
• CPC Class Codes: G04G 19/00 Electric power supply circuits specially adapted for use in electronic time-pieces
• CPC Class Codes: G04G 19/12 Arrangements for reducing power consumption during storage
• CPC Class Codes: G04G 5/00 Setting, i.e. correcting or changing, the time-indication radio-controlled time-pieces G04R

Abstract

An electronically controlled timepiece includes an analog circuit (160) driven by a power source (22), a logic circuit (170) driven by a constant voltage regulator circuit (161) forming part of the analog circuit, an oscillator circuit (51) driven by the constant voltage regulator, a power source switch (162) for cutting off the supply of power to the analog circuit other than the constant voltage regulator circuit from the power source during a time correction operation, and a clock cutoff gate (171) for cutting off a clock input from the oscillator circuit to the logic circuit. During the time correction operation, power consumption is reduced because only the oscillator circuit and the constant voltage regulator circuit are operative. The oscillator circuit is not suspended, and an error in time display is eliminated.

Claims

1. An electronically controlled timepiece comprising:

a power source;

a logic circuit;

an analog circuit driven by said power source, said analog circuit including a power supply circuit arranged in the analog circuit and having an output for driving said logic circuit;

an oscillator circuit driven by the output of said power supply circuit for the logic circuit;

a power source switch for suspending the supply of electrical energy from said power source to said analog circuit except said power supply circuit for said logic circuit during a time correction operation of the electronically controlled timepiece; and

clock input limiter for suspending a clock input from said oscillator circuit to said logic circuit during said time correction operation.

2. An electronically controlled timepiece according to claim 1, wherein the power supply circuit for the logic circuit comprises a constant voltage regulator.

3. An electronically controlled timepiece according to of claim 1, comprising logic circuit initializing means for initializing the internal status of the logic circuit during the time correction operation.

4. An electronically controlled timepiece according to claim 1, comprising:

a mechanical energy source,

a generator which is driven by the mechanical energy source, and generates an electromotive force, thereby supplying electrical energy, and

a rotation controller, driven by the electrical energy, for controlling the rotation period of the generator.

5. A power supply control method for an electronically controlled timepiece comprising a power source, an analog circuit driven by the power source, said analog circuit including a power supply circuit arranged in the analog circuit for a logic circuit, the logic circuit being driven by the output of the power supply circuit therefor, and an oscillator circuit driven by the output of the power supply circuit for the logic circuit, the power supply control method comprising:

the step of suspending the supply of electrical energy from the power source to the analog circuit except the power supply circuit for the logic circuit during a time correction operation of the electronically controlled timepiece, and the step of suspending a clock input from the oscillator circuit to the logic circuit during the time correction operation.

6. A power supply control method for an electronically controlled timepiece according to claim 5, comprising the step of initializing the internal status of the logic circuit during the time correction operation of the electronically controlled timepiece.

7. An electronically controlled timepiece comprising:

a mechanical energy source;

a generator driven by the mechanical energy source, said generator being effective for outputting electrical energy;

a storage unit for storing electrical energy output by the generator;

a rotation controller driven by electrical energy supplied by the storage unit, said rotation controller being effective for controlling the rotation period of the generator;

a power supply control unit for suspending the supply of electrical energy from the storage unit to the rotation controller while the generator stops the operation thereof in response to a time correction operation, and

an indication error corrector unit for correcting an error in time indication until the rotation controller resumes a normal operation wherein the power supply control unit restarts the supply of electrical energy from the storage unit to the rotation controller in response to the activation of the generator.

8. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit is designed to perform a constant quantity correction corresponding to a predetermined value.

9. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit sets a correction value in accordance with a voltage of the storage unit.

10. An electronically controlled timepiece according to claims 7, wherein the indication error corrector unit adjusts a correction value in response to detected temperature.

11. An electronically controlled timepiece according to claim 7, wherein the indication error corrector unit comprises:

a temperature sensor,

a voltage detector for measuring a voltage of the storage unit, and

a correction value setter for setting a correction value based on values detected by the temperature sensor and the voltage detector.

12. An electronically controlled timepiece according to one of claim 7, wherein the power supply control unit comprises a switch which is connected in series with the storage unit and is closed while the generator is running, and is opened while the generator is not running.

13. An electronically controlled timepiece according to claim 12, wherein the switch is a mechanically driven switch.

14. An electronically controlled timepiece according to claim 13, wherein the switch is a mechanically driven switch that is opened when a crown remains pulled out during a time correction mode, and is closed when the crown is pushed in during a normal mode.

15. An electronically controlled timepiece according to claim 7, comprising a second storage unit connected in parallel with the storage unit.

16. A time correction method for an electronically controlled timepiece including a mechanical energy source, a generator driven by the mechanical energy source, said generator being effective for outputting electrical energy, a storage unit for storing electrical energy output by the generator, and a rotation controller driven by electrical energy supplied by the storage unit, said rotation controller being effective for controlling the rotation period of the generator, said time correction method comprising:

the step of suspending the supply of electrical energy from the storage unit to the rotation controller during a time correction operation of the electronically controlled timepiece, and

the step of correcting an error in time indication until the rotation controller resumes a normal operation when the supply of electrical energy from the storage unit to the rotation controller is restarted at the end of the time correction operation.

17. A time correction method for an electronically controlled timepiece according to claim 16, wherein an indication error is corrected by a constant quantity correction corresponding to a predetermined value at the end of the time correction operation.

18. A time correction method for an electronically controlled timepiece according to claim 16, wherein an indication error is corrected by a correction value set in response to a voltage of the storage unit, at the end of the time correction operation.

19. A time correction method for an electronically controlled timepiece according to one of claim 16,

wherein temperature is detected at the end of the time correction operation, and the correction value is adjusted in response to the detected temperature.

20. A timepiece comprising:

a power supply including;

a first power rail and a second power rail;

a power generator selectively placed in an active mode in which power is supplied to said first and second power rails and in an inactive mode in which power is not supplied to said first and second power rails;

a first power storage device for receiving power from said power generator through said first and second power rails;

a first power load coupled to said first power storage device;

a second power load coupled to said first power storage device, said second power load being a voltage regulator having an output coupled to a third power rail to provide a regulated output voltage on said third power rail;

a pulse generator coupled to said third power rail for receiving said regulated output voltage, said pulse generator having a clock output for producing a clocking signal when the voltage of said third power rail is above a minimum active voltage level;

a digital circuit coupled to said third power rail for receiving said regulated output voltage and having a clock input selectively coupled to said clock output;

wherein said first power load is decoupled from said first power storage device and said clock input is decoupled from said clock output when said power generator is in said inactive mode.

21. The timepiece of claim 20 wherein said first power load is an analog circuit.

22. The timepiece of claim 20 wherein said pulse generator and said digital circuit are maintained coupled to said third power rail during both active and inactive modes of said power generator.

23. The timepiece of claim 20 wherein said pulse generator includes at least an oscillator.

24. The timepiece of claim 23, wherein said oscillator is substantially the only load on said third power rail drawing power from said third power rail during said inactive mode.

25. The timepiece of claim 20 further having a logic gate to mask the output of said clock output from said clock input during said inactive mode whereby said clock input is decoupled from said clock output.

26. The timepiece of claim 20, wherein said digital circuit includes a control output node for producing a periodic error correction signal for regulating the generation of power by said power generator when said power generator is in said active mode and for producing no error correction signal when said power generator is said inactive mode.

27. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is larger when the voltage of said third power rail falls below said minimum active voltage level during said inactive mode than when the voltage of said third power rail remains above said minimum active voltage level during said inactive mode.

28. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is dependent on the voltage of said first power storage device.

29. The timepiece of claim 28, wherein the initial amount of power regulation is inversely proportional to the voltage of said first power storage device.

30. The timepiece of claim 28, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is further dependent on temperature.

31. The timepiece of claim 30, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is inversely proportional to temperature.

32. The timepiece of claim 30, wherein said digital circuit further includes:

a temperature sensor to produce a digital representation of the temperature;

a voltage detector coupled to said first power storage device to produce a digital representation of observed voltage across said first power storage device.

33. The timepiece of claim 26, wherein the initial amount of power regulation applied to said power generator at a transition from said inactive mode to said active mode is dependent on initial conditions of said digital circuit following a transition from said inactive mode to said active mode of said power generator.

34. The timepiece of claim 33, wherein said initial conditions are loaded as a numerical value into said digital circuit following said inactive mode.

35. The timepiece of claim 34, wherein said numerical value is fixed such that said digital circuit has the same initial conditions at every transition from said inactive mode to said active mode.

36. The timepiece of claim 34, wherein the numerical value loaded into said digital circuit is a first predetermined value when the voltage of said third power rail remains above said minimum active voltage value during said inactive mode and is a second predetermined value when the voltage of said third power rail falls below said minimum active voltage value during said inactive mode.

37. The timepiece of claim 36, wherein said second predetermined value is greater than said first predetermined value.

38. The timepiece of claim 34, wherein the numerical value loaded into said digital circuit is selected from a table of predetermined values.

39. The timepiece of claim 38, wherein the numerical value to be loaded into said digital circuit is selected from among said predetermined values in said table in accordance with a measured voltage across said first power storage device and a measured temperature.

40. The timepiece of claim 39, wherein said digital circuit further includes:

a temperature sensor to measure said temperature and produce a digital representation of the measured temperature;

a voltage detector coupled to said first power storage device to produce a digital representation of said measured voltage across said first power storage device.

41. The timepiece of claim 20, wherein the duty cycle of said error correction signal is dependent on initial conditions of said digital circuit following a transition from said inactive mode to said active mode of said power generator.

42. The timepiece of claim 26, wherein the initial duty cycle of said error correction signal at a transition from said inactive mode to said active mode is larger when the voltage of said third power rail falls below said minimum active voltage level during said inactive mode than when the voltage of said third power rail remains above said minimum active voltage level during said inactive mode.

43. The timepiece of claim 26, wherein at a transition from said inactive mode to said active mode, the initial duty cycle of said error correction signal is assigned a first predetermined value if the voltage of said third power rail falls below said minimum active voltage level during said inactive mode and assigned a second predetermined value otherwise.

44. The timepiece of claim 26, wherein at a transition from said inactive mode to said active mode, the initial duty cycle of said error correction signal is determined by an assigned value dependent on the voltage of said first power storage device.

45. The timepiece of claim 44, wherein said assigned value is further dependent on temperature.

46. The timepiece of claim 26, wherein said error correction signal is effective for regulating the generation of power by said power generator when said power generator is in said active mode.

47. The timepiece of claim 26, wherein said control output node is coupled to a control input node of said power generator and is effective for retarding the generation of power by said generator in accordance with said error correction signal.

48. The timepiece of claim 26, wherein said power generator includes an AC power generating circuit coupled to a voltage rectifier, and said digital circuit includes at least an error correction circuit for generating said error correction signal, said error correction circuit being responsive to the frequency of said AC power generating circuit.

49. The timepiece of claim 48, wherein said power generator uses a multiple of said clocking signal to obtain a measure of the frequency of said AC power generating circuit, the duty cycle of said error correction signal being adjusted to be proportional to said measure of the frequency of said AC power generating circuit.

50. The timepiece of claim 49, wherein said error correction signal is effective for reducing the frequency of said AC power generating circuit whereby a feedback system is established.

51. The timepiece of claim 50, wherein said error correction circuit includes a counter for determining the application of said error correction signal, said counter being reset to an initial count value at a transition from said inactive mode to said active mode.

52. The timepiece of claim 51, wherein said counter is reset to the same predetermined count value at every transition from said inactive mode to said active mode.

53. The timepiece of claim 51, wherein said counter is reset to a first predetermined count value in response to the voltage of said third power rail remaining above said minimum active voltage during said inactive mode, and is reset to a second predetermined count value in response to the voltage of said third power rail falling below said minimum active voltage during said inactive mode.

54. The timepiece of claim 53, wherein said second predetermined count value is greater than said first predetermined count value.

55. The timepiece of claim 53, wherein said second predetermined count value is selected from a table of available count values.

56. The timepiece of claim 55, wherein a target count value from among said table of available count values is selected as said second predetermined count value in accordance with the voltage across said first power storage device.

57. The timepiece of claim 55, wherein a target count value from among said table of available count values is selected as said second predetermined count value in accordance with the temperature of said pulse generator.

58. The timepiece of claim 20, further having a second power storage device coupled between said first and second power rails, said first power storage device being decoupled from at least one of said first and second power rails during said inactive mode and being re-coupled to said first and second power rails in response to said active mode.

59. The timepiece of claim 58, wherein said second power storage device remains coupled to said first and second power rails during both of said active mode and inactive mode.

60. The timepiece of claim 58, wherein said first power storage device has a greater power storage capacity than said second power storage device.

61. The timepiece of claim 60, wherein said first and second power storage devices are respective first and second capacitors.