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

• US 6,956,794 B2
• Filed: 02/06/2003
• Issued: 10/18/2005
• 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: Shimizu, Eisaku, Koike, Kunio, Nakamura, Hidenori
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): GOODWIN, JEANNE M
• Application Number:
  US10/361,074
• Publication Number:
  US 20030128631A1
• Time in Patent Office: 985 Days
• Field of Search: 368203-205, 368/76, 368/64, 320/103, 320/148, 320/149, 320/152, 320/155, 320/166, 320/167
• US Class Current: 368/203
• 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 mechanical energy source;

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

a rotation controller driven by electrical energy, and effective for controlling a rotation period of the generator;

a main storage unit for storing electrical energy supplied by the generator to drive the rotation controller;

an auxiliary storage unit connected in parallel with the main storage unit through a mechanically driven switch that is responsive to a time correction operation; and

a charge control circuit arranged between the main storage unit and the auxiliary storage unit, said charge control circuit being effective for adjusting charging currents to the main storage unit and the auxiliary storage unit, and for controlling a direction and a magnitude of a current flow between the main storage unit and the auxiliary storage unit.

2. An electronically controlled timepiece according to claim 1, wherein:

the charge control circuit makes the charging current to the auxiliary storage unit smaller than the charging current to the main storage unit when the mechanically driven switch is closed to charge the main storage unit and the auxiliary storage unit with electrical energy from the generator; and

the charge control circuit further allows the auxiliary storage unit to charge the main storage unit when the voltage of the auxiliary storage unit is higher than the voltage of the main storage unit.

3. An electronically controlled timepiece according to claim 2, wherein the charge control circuit comprises a passive element only.

4. An electronically controlled mechanical timepiece according to claim 1, wherein the main storage unit has a capacitance set substantially equal to or lower than a capacitance of the auxiliary storage unit.

5. An electronically controlled timepiece according to claim 1, wherein the mechanically driven switch is opened during the time correction operation, and is closed at the end of the time correction operation.

6. An electronically controlled timepiece according to claim 1, wherein the charge control circuit comprises a resistor and a diode connected in parallel with the resistor;

and

wherein the diode is configured with the reverse direction thereof aligned with the direction of a current charging the auxiliary storage unit from the generator, and the forward direction thereof aligned with the direction of a current of the auxiliary storage unit charging the main storage unit.

7. An electronically controlled timepiece according to claim 1, wherein the charge control circuit comprises only a diode having a reverse leakage current, and wherein the diode is configured with the reverse direction thereof aligned with the direction of a current charging the auxiliary storage unit from the generator and the forward direction thereof aligned with the direction of a current of the auxiliary storage unit charging the main storage unit.

8. An electronically controlled timepiece according to claim 1, wherein the charge control circuit comprises a resistor and a one-way element connected in parallel with the resistor;

and

wherein the one-way element is configured to cut off a current flowing in a direction to charge the auxiliary storage unit from the generator and to conduct a current of the auxiliary storage unit flowing in a direction to charge the main storage unit.

9. An electronically controlled timepiece according to claim 1, further including an indication error corrector unit for correcting an error in time indication until the rotation controller resumes a normal operation when the supply of electrical energy of the main storage unit to the rotation controller is restarted with the mechanically driven switch closed.

10. An electronically controlled timepiece according to claim 9, wherein the indication error corrector unit is designed to perform a constant quantity correction corresponding to a predetermined value.

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

12. An electronically controlled timepiece according to claim 9, wherein the indication error corrector unit adjusts a correction value in response to detected temperature.

13. An electronically controlled timepiece according to claim 9, wherein the indication error corrector unit includes:

a temperature sensor;

a voltage detector for measuring a voltage of the storage unit;

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

14. A power supply control method for an electronically controlled timepiece having a mechanical energy source, a generator for outputting electrical energy and driven by the mechanical energy source, and a rotation controller for controlling the rotation period of the generator and driven by electrical energy, the power supply control method comprising:

a step of connecting an auxiliary storage unit in parallel with a main storage unit through a mechanically driven switch, wherein the main storage unit stores electrical energy supplied by the generator to drive the rotation controller;

a step of opening the mechanically driven switch during a time correction operation of the electronically controlled timepiece; and

a step of flowing a current from the auxiliary storage unit to the main storage unit to charge the main storage unit when the voltage of the auxiliary storage unit is higher than the voltage of the main storage unit with the mechanically driven switch closed at the end of the time correction operation; and

a step of making a charging current supplied from the generator to the main storage unit greater than a charging current supplied from the generator to the auxiliary storage unit when the voltage of the auxiliary storage unit is not higher than the voltage of the main storage unit.

15. A timepiece comprising:

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 second power storage device coupled between said first and second power rails;

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

a second power load couple 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;

a current-flow-discriminating circuit effective for providing a first impedance to current flow in one direction and a second impedance to current flow in an opposite direction, said first impedance being greater than said second impedance;

wherein said first storage device is coupled to said second storage device through said current-flow-discriminating circuit; and

wherein said current-flow-discriminating circuit is arranged to provide said first impedance to the flow of current from said second power storage device to said first power storage device, and arranged to provide said second impedance to current flow from said first power storage device to said second power storage device.

16. The timepiece of claim 15, wherein said current-flow-discriminating circuit includes a diode.

17. The timepiece of claim 16, wherein said current-flow-discriminating circuit includes a resistor in parallel with said diode.

18. The timepiece of claim 15, wherein said power generator is connected directly to said second power storage device.

19. The timepiece of claim 15 wherein said first and second power storage devices are respective first and second capacitors.

20. The timepiece of claim 19, wherein said first capacitor has a greater capacitance than said second capacitor.

21. The timepiece of claim 15, wherein said first power storage device is decoupled from at least one of said first and second power rails during said inactive mode and is re-coupled to said first and second power rails in response to said active mode.

22. The timepiece of claim 21, wherein said power generator is connected directly to said second power storage device.

23. The timepiece of claim 21 wherein said first and second power storage devices are respective first and second capacitors.

24. The timepiece of claim 23, wherein said first capacitor has a greater capacitance than said second capacitor.

25. The timepiece of claim 21, wherein said current-flow-discriminating circuit includes a diode.

26. The timepiece of claim 25, wherein said current-flow-discriminating circuit includes a resistor in parallel with said diode.

27. The timepiece of claim 15, wherein said power supply is effective for providing electrical power to a time piece.

28. The timepiece of claim 15, further including a user-controlled mode selector for selectively placing said power generator in said active mode and in said inactive mode, said user-controlled mode selector including:

a first inverter and a second inverter;

a first signal line for connecting the output of said first inverter to the input of said second inverter;

a second signal line for connecting the output of said second inverter to the input of said first inverter; and

a switch for connecting a signal input line to one of said first and second signal lines to indicate said inactive mode, and for connecting said signal input line to the other of said first and second signal lines to indicate said active mode.