Analog electronic timepiece drive circuitry for energizing stepping motor drive coil in full and intermediate excitation states, and method therefor

Claim 2

In an electronic timepiece having a stepping motor comprised of a stator, rotor and drive coil; and time-indicating means connected to the stepping motor for indicating time in response to rotation of the rotor: circuit means for periodically energizing the drive coil by periodically applying thereto drive signals so as to rotationally drive the rotor in a stepwise manner in a forward direction of rotation, said circuit means including means operative during each energization period for sequentially energizing the drive coil first in a full excitation state by applying thereto a first drive signal component composed of a pulse of uniform voltage level to apply a given effective power to the drive coil effective to at least initiate driving of the rotor in the forward direction from an initial position through at least a 180° forward angle of rotation to a new position, and then in an intermediate excitation state by applying thereto a second drive signal component to apply effective power less than said given effective power to the drive coil effective to ensure completion of the driving of the rotor through said at least 180° forward angle of rotation by preventing return rotation of the rotor in the reverse direction back to its initial position after the rotor has forwardly rotated through a certain angular extent towards its new position thereby stabilizing the operation of the stepping motor.

Claim 3

An electronic timepiece according to claim 1; wherein said circuit means includes means for producing and applying to the drive coil during each energization period a second drive signal component composed of a pulse of predetermined pulse width to energize the drive coil in said intermediate excitation state.

Claim 4

An electronic timepiece according to claim 1; wherein said circuit means includes means for producing and applying to the drive coil during each energization period a second drive signal component composed of a plurality of pulses of the same polarity to energize the drive coil in said intermediate excitation state.

Claim 5

An electronic timepiece according to claim 1; wherein said circuit means comprises means for periodically generating drive signals of alternate polarity and successively applying the drive signals to the drive coil in successive energization periods to energize the dirve coil so as to rotationally drive the rotor, each drive signal having a first drive signal component effective to energize the drive coil in the full excitation state and a second drive signal component effective to energize the drive coil in the intermediate excitation state.

Claim 6

An electronic timepiece according to claim 4; wherein the first drive signal component of each drive signal has greater effective power that the second drive signal component.

Claim 7

An electronic timepiece according to claim 4; wherein the first drive signal component of each drive signal has a greater duration than the second drive signal component.

Claim 8

An electronic timepiece according to claim 4; wherein each drive signal comprises a compound drive pulse having a normal drive pulse component corresponding to the first drive signal component and effective to energize the drive coil in the full excitation state to at least initiate driving of the rotor in the forward direction through said at least 180° forward angle of rotation under normal loading, and a secondary drive pulse component corresponding to the second drive signal component and effective to energize the drive coil in the intermediate excitation state to ensure completion of the driving of the rotor through said at least 180° forward angle or rotation.

Claim 9

An electronic timepiece according to claim 1; wherein the secondary drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity each having a pulse width substantially less than that of the normal drive pulse component.

Claim 10

An electronic timepiece according to claim 8; wherein at least some of the plurality of pulses which comprise the secondary drive pulse component of each compound drive pulse have different pulse widths.

Claim 11

An electronic timepiece according to claim 5; wherein each drive signal comprises a compound drive pulse having a first drive signal component which includes a correction drive pulse component effective to energize the drive coil in the full excitation state to at least initiate driving of the rotor in the forward direction through said at least 180° forward angle of rotation under worst case loading, and a secondary drive pulse component corresponding to the second drive signal component and effective to energize the drive coil in the intermediate excitation state to ensure completion of the driving of the rotor through said at least 180° forward angle of rotation.

Claim 12

An electronic timepiece according to claim 10; wherein the secondary drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity each having a pulse width substantially less than that of the normal drive pulse component.

Claim 13

An electronic timepiece according to claim 11; wherein at least some of the plurality of pulses which comprise the secondary drive pulse component of each compound drive pulse have different pulse widths.

Claim 14

An electronic timepiece according to claim 10; wherein the correction drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity.

Claim 15

An electronic timepiece according to any one of claims 1, 4, 7 and 10; wherein said circuit means includes means for periodically energizing the drive coil in energization periods longer than one second.

Claim 16

An electronic timepiece according to any one of claims 4, 7 and 10; wherein the first drive signal component of each drive signal has a duration of about 6.8 milliseconds.

Claim 19

A method according to claim 16; wherein the step of energizing the drive coil includes producing and applying to the drive coil during each energization period a second drive signal component composed of a pulse of predetermined pulse width to energize the drive coil in said intermediate excitation state.

Claim 20

A method according to claim 16; wherein the step of energizing the drive coil includes producing and applying to the drive coil during each energization period a second drive signal component composed of a plurality of pulses of the same polarity to energize the drive coil in said intermediate excitation state.

Claim 21

A method according to claim 16; wherein the step of energizing the drive coil comprises periodically generating drive signals of alternate polarity and successively applying the drive signals to the drive coil in successive energization periods to energize the drive coil so as to rotationally drive the rotor, each drive signal having a first drive signal component effective to energize the drive coil in the full excitation state and a second drive signal component effective to energize the drive coil in the intermediate excitation state.

Claim 22

A method according to claim 19; wherein the first drive signal component of each drive signal has greater effective power than the second drive signal component.

Claim 23

A method according to claim 19; wherein the first drive signal component of each drive signal has a greater duration than the second drive signal component.

Claim 24

A method according to claim 19; wherein each drive signal comprises a compound drive pulse having a normal drive pulse component corresponding to the first drive signal component and effective to energize the drive coil in the full excitation state to at least initiate driving of the rotor in the forward direction through said at least 180° forward angle of rotation under normal loading, and a secondary drive pulse component corresponding to the second drive signal component and effective to energize the drive coil in the intermediate excitation state to ensure completion of the driving of the rotor through said at least 180° forward angle of rotation.

Claim 25

A method according to claim 22; wherein the secondary drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity each having a pulse width substantially less than that of the normal drive pulse component.

Claim 26

An electronic timepiece according to claim 23; wherein at least some of the plurality of pulses which comprise the secondary drive pulse component of each compound drive pulse have different pulse widths.

Claim 27

A method according to claim 19; wherein each drive signal comprises a compound drive pulse having a first drive signal component which includes a correction drive pulse component effective to energize the drive coil in the full excitation state to at least initiate driving of the rotor in the forward direction through said at least 180° forward angle of rotation under worst case loading, and a secondary drive pulse component corresponding to the second drive signal component and effective to energize the drive coil in the intermediate excitation state to ensure completion of the driving of the rotor through said at least 180° forward angle of rotation.

Claim 28

A method according to claim 25; wherein the secondary drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity each having a pulse width substantially less than that of the normal drive pulse component.

Claim 29

A method according to claim 26; wherein at least some of the plurality of pulses which comprise the secondary drive pulse component of each compound drive pulse have different pulse widths.

Claim 30

A method according to claim 25; wherein the correction drive pulse component of each compound drive pulse comprises a plurality of pulses of the same polarity.

Claim 33

An electronic timepiece according to claim 3; wherein the second drive signal component of each drive signal comprises a plurality of pulses each having the same pulse width.

Claim 34

An electronic timepiece according to claim 31; wherein the plurality of pulses which comprise each second drive signal component each have the same duty ratio.

Claim 35

An electronic timepiece according to claim 3; wherein the second drive signal component of each drive signal comprises a plurality of pulses each having the same duty ratio.

Claim 36

In an electronic timepiece having a stepping motor comprised of a stator, rotor and drive coil; and time-indicating means connected to the stepping motor for indicating time in response to rotation of the rotor; circuit means for periodically energizing the drive coil by periodically applying thereto drive signals so as to rotationally drive the rotor in a stepwise manner in a forward direction of rotation, said circuit means including means operative during each energization period for sequentially energizing the drive coil first in a full excitation state by applying thereto a first drive signal component composed of a pulse of uniform voltage level to apply a given effective power to the drive coil effective to at least initiate driving of the rotor in the forward direction from an initial position through a predetermined forward angle of rotation to a new position, and then in an intermediate excitation state by applying thereto a second drive signal component composed of a plurality of pulses each having the same pulse width and the same duty ratio to apply effective power less than said given effective power to the drive coil effective to ensure completion of the driving of the rotor through said predetermined forward angle of rotation by preventing return rotation of the rotor in the reverse direction back to its initial position after the rotor has forwardly rotated through a certain angular extent towards its new position thereby stabilizing the operation of the stepping motor.

Claim 37

In an electronic timepiece having a stepping motor comprised of a stator, rotor and drive coil; and time-indicating means connected to the stepping motor for indicating time in response to rotation of the rotor; circuit means for periodically energizing the drive coil by periodically applying thereto drive signals so as to rotationally drive the rotor in a stepwise manner in a forward direction of rotation, said circuit means including means operative during each energization period for sequentially energizing the drive coil first in a full excitation state by applying thereto a first drive signal component composed of a pulse of uniform voltage level to apply a given effective power to the drive coil effective to at least initiate driving of the rotor in the forward direction from an initial position through a predetermined forward angle of rotation to a new position, and then in an intermediate excitation state by applying thereto a second drive signal component composed of a plurality of pulses each having the same pulse width and the same duty ratio to apply effective power less than said given effective power to the drive coil effective to ensure completion of the driving of the rotor through said predetermined forward angle of rotation by preventing return rotation of the rotor in the reverse direction back to its initial position after the rotor has forwardly rotated through a certain angular extent towards its new position thereby stabilizing the operation of the stepping motor.

Claim 38

An electronic timepiece according to claim 34; wherein said circuit means includes means for producing and applying drive signals to the drive coil to effect stepwise driving of the rotor through predetermined forward angles of rotation of at least 180°.