Electronic watch

Abstract

An electronic watch 400 which comprises a power supply 401 and a watch circuit 402. The watch circuit 402 comprises an oscillator circuit 403, a frequency divider circuit 404, a drive pulse generation means 405, a drive motor 406 which, in response to a drive pulse P1 that is output by the above-noted drive pulse generation means 405, drives at least one of the hour / minute, second, and functional hands including chronograph hands, a drive circuit means 407 which controls the drive of the drive motor 406, a drive circuit control means 408 which controls the above-noted drive circuit means 407, and a control condition detection means 409 which is connected to the above-noted drive circuit control means 408 and which detect the control condition in the drive circuit control means 408, the control condition detection means 409 being provided with a non-proper condition detection means 410 which senses the occurrence of a condition in which it is not possible to properly drive the above-noted drive motor 406 under a prescribed condition in a prescribed control mode currently being executed, and a control mode change-instructing means 411 which, in response to a detection signal of the above-noted non-proper condition detection means 410, issues an instruction to the drive circuit control means 408 to change the control mode currently being executed.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an electronic watch, and more specifically it relates to an electronic watch having a drive motor which is driven by a normal hand-movement drive pulse and a drive motor which is driven by a non-normal hand-movement drive pulse that differs from the above-noted normal hand-movement drive pulse, so that even if the power supply voltage or drive conditions change, a proper drive condition is maintained for the drive motor which is driven by a normal hand-movement drive pulse, and which can also achieve low-power-consumption operation[0003]2. Description of the Related Art[0004]There is a usual type of stepping motor for an electronic watch rotates in the forward direction only in response to, for example, an input signal, and is configured so as not to rotate in the reverse direction.[0005]For this reason, if it is desirable to cause the rotor to rotate in the reverse direction, for exampl...

AI Technical Summary

Benefits of technology

[0114]An object of the present invention is to provide an electronic watch which offers an improvement with respect to the above-noted drawback in the prior art, this electronic watch either comprising a drive motor which is driven by a normal hand-drive pulse and a drive motor which is driven by a non-normal hand-drive pulse, or comprising a single drive motor which is driven by normal hand-drive pulse and a non-normal hand-drive pulse, and being capable not only of maintaining accuracy timekeeping display or functional display including chronograph display, but also of achieving low power consumption.

[0116]The second object of the present invention is to provide an electronic watch in which there exist at least two drive motors adjacent to one another, and which has a function that prevents erroneous detection in the load compensation operation of one drive motor caused by magnetic interference thereto from the other drive motor.

[0119]That is, in an electronic watch according to the present invention in supplying a prescribed drive pulse to an appropriate drive motor via the drive circuit control means so as to cause the execution by the above-noted drive motor of a prescribed display operation, in addition to monitoring the control mode which is currently being executed by the drive circuit control means, in the case in which, in this control mode, because of a change in the drive voltage of the power supply or a change in another condition, a condition occurs in which the reliability with regard to a prescribed display operation of the drive motor decreases, the control mode is changed either by causing the above-noted drive circuit control means to stop the currently executing control mode, or causing it to execute a different control mode, or by performing processing, for example, to change the output condition of the drive pulse, so that regardless of the manner in which the drive environment changes, it is not only possible to maintain a proper drive condition in the above-noted drive motor, but also to drive the above-noted drive motor at all times with an optimum low power consumption, thereby enabling the achievement of operation with low power consumption.

Problems solved by technology

However, the reverse rotation operation of the above-noted stepping motor exhibits a narrower range of operating voltage than for forward operation, and it is particularly difficult to achieve normal operation at a low voltage.

Additionally, because the drive frequency for fast forward drive is high, the pulse width must be made narrow, making normal operation at a low voltage difficult.

Thus, when one stepping motor rotates, it magnetically interferes with the other stepping motor.

In a motor such as the first stepping motor, in which detection is made of rotation and non-rotation, the above-noted magnetic interference can result in a misjudgment that the first stepping motor has rotated, when in fact it has not rotated, thereby resulting in inhibiting of the output of the compensation drive pulse, this resulting in a disturbance of the timekeeping by the watch.

Thus, although the first stepping motor has not actually rotated, an erroneous detection to the effect that it did not rotate occurs, and a compensation drive pulse Ph is not output as a result.

Thus, at a low voltage at which drive is not possible, drive is only possible at a power supply voltage Vc of 2.6 V or greater.

However, at a high power supply voltage Vc, the normal pulse Ps8 has more drive capacity than is necessary, so that the power consumption becomes large.

However, because with the normal pulse Ps4 drive is not possible with the power supply voltage Vc of 1.7 V, the compensation pulse Psh is output to perform compensation drive, the normal pulse being returned to the next larger normal pulse Ps5 the next time output is made.

Although the current consumption of the compensation pulse Psh is larger than with a normal pulse Ps, this occurs only one time in 100, so that th effect extremely small and not enough to cause a problem.

However, it is known that with a solar watch the power supply voltage varies widely, making it impossible to obtain sufficient motor drive energy with a fixed pulse width when performing non-normal pulse drive such as high-speed pulse drive and reverse pulse drive at low voltages, another associated problem being that a high voltages rotor overrun occurs, preventing proper drive, and thereby limiting the voltage range over which drive is possible.

Accommodation of the above-noted functions in solar watches, in which the power supply voltage varies widely, is therefore not possible.

However, with multistage load compensation, because of the time period for detection an the time period of output of a compensation drive pulse, the amount of time until the output of the next pulse becomes long, this posing the problem of preventing high-speed drive.

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