Electronic device, electronically-controlled mechanical timepiece, and electronic device controlling method

• US 6,693,852 B2
• Filed: 03/22/2002
• Issued: 02/17/2004
• Est. Priority Date: 03/29/2001
• 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): Martin, David
• Assistant Examiner(s): Lindinger, Michael L.
• Application Number:
  US10/104,935
• Publication Number:
  US 20020141528A1
• Time in Patent Office: 697 Days
• Field of Search: 368/203-204, 368/64, 368/66, 322/8, 322/24, 322/29, 322/46
• 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

Abstract

An electronic device in which a braking torque can be increased while reduction in power generation is suppressed, and in which a rotor is prevented from stopping or rotating at an excessive speed. Such an electronic device includes a generator which is driven by an mechanical energy source and a rotation controller which controls the rotational period of the generator. The rotation controller includes two switches which connect both terminals of the generator in the form of a closed loop, a chopping signal generator which generates a chopping signal that is applied to the switches, and a brake control circuit which performs chopper control of the generator by selectively switching between three brake control modes including a high-power brake control mode in which the effective braking force generated by applying the chopping signal is relatively large a low-power brake control mode in which the effective braking force is relatively small, and a mid-power brake control mode in which the effective braking force is between that of the high- and low-power brake control modes.

Claims

1. An electronic device, comprising:

a mechanical energy source;

a generator having two terminals, and configured to be driven by the mechanical energy source, to generate induced electrical power, and to provide electrical energy; and

a rotation controller configured to be driven by the electrical energy, and to control a rotation period of the generator, the rotation controller including

a switch that is able to selectively connect the terminals of the generator in the form of a closed loop,

a chopping signal generator configured to generate a chopping signal that is applied to the switch for brake control of the generator, and

a brake controller configured to control the chopping signal generator, and thereby control a braking force applied to the generator, by selectively switching between at least three brake control modes, including a high-power brake control mode in which an effective braking force is large, a mid-power brake control mode in which the effective braking force is less than the effective braking force of the high-power brake control mode, and a low-power brake control mode in which the effective braking force is less than the effective braking force of the mid-power brake control;

wherein the mid-power brake control mode is performed in a first transitional period during which the low-power brake control mode is switched to the high-power brake control mode, or in a second transitional period during which the high-power brake control mode is switched to the low-power brake control mode, or in both the first and second transitional periods.

2. An electronic device according to claim 1, wherein:

the chopping signal generator is configured to generate at least three chopping signals, each having a different duty factor or a different frequency than the others, to generate different effective braking forces depending on which chopping signal is applied to the switch, and

the brake controller includes a chopping signal selector configured to select one of the at least three chopping signals to be applied to the switch.

3. An electronic device according to claim 1, wherein, in switching from the high-power brake control mode to the low-power brake control mode the applied braking force is gradually reduced, and, in switching from the low-power brake control mode to the high-power brake control mode the applied braking force is gradually increased.

4. An electronic device according to claim 3, wherein, when the low-power brake control mode is switched to the high-power brake control mode, the effective braking force is gradually increased from a predetermined value.

5. An electronic device according to claim 3, wherein, when the high-power brake control mode is switched to the low-power brake control mode, the effective braking force is gradually reduced from a predetermined value.

6. An electronic device according to claim 4, wherein the predetermined value is based on the effective braking force which is applied immediately before the brake control mode is switched.

7. An electronic device according to claim 5, wherein the predetermined value is based on the effective braking force which is applied immediately before the brake control mode is switched.

8. An electronically-controlled, mechanical timepiece, comprising:

a mechanical energy source;

a generator having two terminals, and configured to be driven by the mechanical energy source, to generate induced electrical power, and to provide electrical energy;

a time display configured to be operated in association with the rotation of the generator; and

a rotation controller configured to be driven by the electrical energy, and to control the rotation period of the generator, the rotation controller including

a switch that is able to selectively connect the terminals of the generator in the form of a closed loop,

a chopping signal generator configured to generate a chopping signal that is applied to the switch for brake control of the generator, and

a brake controller configured to control the chopping signal generator, and thereby control a braking force applied to the generator, by selectively switching between at least three brake control modes, including a high-power brake control mode in which an effective braking force is large, a mid-power brake control mode in which the effective braking force is less than the effective braking force of the high-power brake control, and a low-power brake control mode in which the effective braking force is less than the effective braking force of the mid-power brake control mode;

wherein the mid-power brake control mode is performed in a first transitional period during which the low-power brake control mode is switched to the high-power brake control mode, or in a second transitional period during which the high-power brake control mode is switched to the low-power brake control mode, or in both the first and second transitional periods.

9. An electronic device according to claim 8, wherein:

the chopping signal generator is configured to generate at least three chopping signals, each having a different duty factor or a different frequency than the others, to generate different effective braking forces depending on which chopping signal is applied to the switch, and

the brake controller includes a chopping signal selector configured to select one of the at least three chopping signals to be applied to the switch.

10. An electronic device according to claim 8, wherein, in switching from the high-power brake control mode to the low-power brake control mode the applied braking force is gradually reduced, and, in switching from the low-power brake control mode to the high-power brake control mode the applied braking force is gradually increased.

11. An electronic device according to claim 10, wherein, when the low-power brake control mode is switched to the high-power brake control mode, the effective braking force is gradually increased from a predetermined value.

12. An electronic device according to claim 10, wherein, when the high-power brake control mode is switched to the low-power brake control mode, the effective braking force is gradually reduced from a predetermined value.

13. An electronic device according to claim 11, wherein the predetermined value is based on the effective braking force which is applied immediately before the brake control mode is switched.

14. An electronic device according to claim 12, wherein the predetermined value is based on the effective braking force which is applied immediately before the brake control mode is switched.

15. A method for controlling an electronic device which includes a mechanical energy source;

a generator having two terminals, and configured to be driven by the mechanical energy source, to generate induced electrical power, and to provide electrical energy; and

a rotation controller configured to be driven by the electrical energy and to control a rotation period of the generator, the method comprising the steps of;

applying a chopping signal to a switch that is able to selectively connect the terminals of the generator in the form of a loop; and

controlling the applying of the chopping signal, and thereby controlling a braking force applied to the generator, by selectively switching between at least three brake control modes, including a high-power brake control mode in which an effective braking force is large, a mid-power brake control mode in which the effective braking force is less than the effective braking force of the high-power brake control mode, and a low-power brake control mode in which the effective braking force is less than the effective braking force of the mid-power brake control mode;

wherein the mid-power brake control mode is performed in a first transitional period during which the low-power brake control mode is switched to the high-power brake control mode, or in a second transitional period during which the high-power brake control mode is switched to the low-power brake control mode, or in both the first and second transitional periods.