HK1160234A - Stepping motor control circuit and analog electronic timepiece - Google Patents

Description

Stepping motor control circuit and analog electronic timepiece

Technical Field

The present invention relates to a stepping motor control circuit and an analog electronic timepiece using the stepping motor control circuit and a secondary battery as a power source.

Background

In the past, stepping motors have been used for time hand driving of analog electronic timepieces.

In addition, electronic watches have been developed that use a secondary battery as a power source and store power in the secondary battery using a power generation unit such as a solar cell.

In a conventional electronic timepiece using a secondary battery as a power source, a voltage detection circuit such as a comparator is installed to suppress overcharge of the secondary battery, and a discharge unit for increasing energy of a motor drive pulse is operated to suppress overcharge of the secondary battery when a voltage of the secondary battery exceeds a predetermined value (see, for example, patent document 1).

The overcharge of the secondary battery can be suppressed by controlling the voltage of the secondary battery as described above, but since the voltage of the secondary battery is detected by using a voltage detection dedicated circuit such as a comparator, there are problems that the circuit scale increases, it is difficult to achieve miniaturization, and the cost increases.

In addition, when the secondary battery is overdischarged, if the overdischarge cannot be notified as soon as possible without being in an environment where the secondary battery can be automatically charged, there is a possibility that an erroneous operation may occur or the secondary battery may fall into a function stop state.

[ patent document 1 ] Japanese patent application laid-open No. 2008-256453

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to detect that a secondary battery is out of a suitable charging region without designing a circuit dedicated to voltage detection such as a comparator circuit.

Further, the present invention is directed to suppress deterioration of a secondary battery due to overcharge without designing a circuit dedicated to voltage detection such as a comparator circuit.

According to the present invention, there is provided a stepping motor control circuit comprising: a secondary battery as a power source that supplies at least electric power to the stepping motor; a rotation detection unit that detects a rotation condition of the stepping motor; and a control unit that selects a drive pulse having an energy corresponding to a rotation state of the stepping motor from a plurality of types of drive pulses and drives the stepping motor, wherein the control unit performs a predetermined operation corresponding to a voltage of the secondary battery when it is determined that the voltage of the secondary battery is outside a charging suitable region.

For example, the present invention provides a stepping motor control circuit, comprising: a secondary battery as a power source that supplies at least electric power to the stepping motor; a rotation detection unit that detects a rotation condition of the stepping motor; and a control unit that selects a drive pulse having energy corresponding to a rotation state of the stepping motor from a plurality of types of drive pulses and drives the stepping motor, wherein when it is determined that the stepping motor can be rotated by an overcharge-indicating drive pulse having a predetermined energy, the control unit changes the drive pulse to an overconsumption drive pulse having energy larger than that of the overcharge-indicating drive pulse and drives the stepping motor.

Further, according to the present invention, there is provided an analog electronic timepiece comprising: the stepping motor control circuit is characterized in that the stepping motor control circuit is adopted as a control unit for controlling the stepping motor.

According to the stepping motor control circuit of the invention, the secondary battery can be detected to be out of the charging suitable area without designing a special voltage detection circuit such as a comparison circuit.

Further, according to the stepping motor control circuit of the present invention, it is possible to suppress deterioration of the secondary battery due to overcharge without designing a circuit dedicated to voltage detection such as a comparator circuit.

Further, according to the analog electronic timepiece of the present invention, it is possible to suppress deterioration of the secondary battery due to overcharge without designing a circuit dedicated to voltage detection such as a comparator circuit, and it is possible to achieve miniaturization.

Drawings

Fig. 1 is a block diagram of an analog electronic timepiece according to an embodiment of the present invention.

Fig. 2 is a flowchart of a stepping motor control circuit and an analog electronic timepiece according to embodiment 1 of the present invention.

Fig. 3 is a flowchart of a stepping motor control circuit and an analog electronic timepiece according to embodiment 2 of the present invention.

Fig. 4 is a flowchart of a stepping motor control circuit and an analog electronic timepiece according to embodiment 3 of the present invention.

Fig. 5 is a flowchart of a stepping motor control circuit and an analog electronic timepiece according to embodiment 4 of the present invention.

Description of the reference symbols

101 an oscillating circuit; a divide by 102 circuit; 103 a degradation count circuit; 104 a control circuit; 105 a main drive pulse generating circuit; 106 correction drive pulse generating circuit; 107 motor drive circuits; 108 a stepper motor; 109 a rotation detection circuit; 110 an analog display unit; 111 a secondary battery; 112 solar cells.

Detailed Description

Fig. 1 is a block diagram of an analog electronic timepiece using a stepping motor control circuit according to an embodiment of the present invention, and is a block diagram common to each of the embodiments described later, and shows an example of an analog electronic wristwatch.

In fig. 1, the analog electronic timepiece includes: an oscillation circuit 101 that generates a signal of a predetermined frequency; a frequency dividing circuit 102 that divides a signal generated by the oscillation circuit 101 to generate a clock signal as a reference for timing; a control circuit 104 that performs various controls such as a clock operation of the clock signal, control of each electronic circuit element constituting an analog electronic timepiece, and control of changing a drive pulse; and a degradation count circuit 103 that outputs a degradation signal for degrading the main drive pulse P1 to the main drive pulse generating circuit 105 every time the clock signal is clocked for a predetermined time.

The analog electronic timepiece further includes: a main drive pulse generation circuit 105 that selectively outputs a plurality of types of main drive pulses P1 having different energies from each other in accordance with a main drive pulse control signal from the control circuit 104, and that lowers (degrades) the level of the main drive pulse P1 by one level in response to the degradation signal; a correction drive pulse generation circuit 106 that outputs a correction drive pulse P2 having energy larger than that of each main drive pulse P1, in accordance with a correction drive pulse control signal from the control circuit 104; and a motor drive circuit 107 that drives the stepping motor 108 to rotate in response to the main drive pulse P1 from the main drive pulse generating circuit 105 and the correction drive pulse P2 from the correction drive pulse generating circuit 106.

The analog electronic timepiece further includes: a stepping motor 108 driven to rotate by a motor drive circuit 107; an analog display unit 110 having a time hand for displaying time driven to rotate by the stepping motor 108, a calendar display unit, and the like; a rotation detection circuit 109 that detects an induced signal VRs generated by the stepping motor 108 in a predetermined rotation detection interval and outputs a detection signal indicating a rotation state; a secondary battery 111 as a power source that supplies electric power to each electronic circuit element of an analog electronic timepiece represented by the stepping motor 108; and a solar cell 112 that charges the secondary battery 111.

A rotation detection section that detects whether the stepping motor 108 has rotated is set immediately after the rotational driving by the main drive pulse P1, and the rotation detection circuit 109 determines whether the induced signal VRs generated due to the free vibration immediately after the stepping motor 108 is driven exceeds a predetermined reference threshold voltage Vcomp, thereby detecting a rotation condition indicating whether the stepping motor 108 has rotated normally (i.e., the drive energy of the main drive pulse P1 is sufficient or insufficient).

The control circuit 104 determines the rotation state of the stepping motor 108 based on the detection signal from the rotation detection circuit 109, outputs a control signal to the main drive pulse generation circuit 105 or the correction drive pulse generation circuit 106, and performs pulse control such as up-conversion and down-conversion of the main drive pulse P1 and drive control based on the correction drive pulse P2. As for the drive pulse, plural kinds of drive pulses different in energy from each other (i.e., different in pulse width from each other) are prepared as the main drive pulse P1, and a correction drive pulse P2 capable of forcibly rotating the stepping motor 108, which is larger in energy (i.e., larger in pulse width) than the respective main drive pulses P1, is prepared.

The minimum drive pulse P1min of the main drive pulses P1 is a main drive pulse (overcharge instruction drive pulse Pkj) indicating that the secondary battery 111 is overcharged (that is, the secondary battery 111 is in a state of being charged to a predetermined voltage (for example, the highest rated charge voltage defined so as not to shorten the life of the secondary battery 111) or more and is outside the charge suitable region).

The pulse width of the overcharge instruction drive pulse Pkj is set so that the stepping motor 108 cannot be rotated because energy is small when the voltage of the secondary battery 111 is not overcharged but is equal to or lower than the predetermined voltage, but the energy of the drive pulse is increased although the pulse width is small when the secondary battery 111 is overcharged and the voltage is equal to or higher than the predetermined voltage, and the stepping motor 108 can be rotated.

When it is determined that the overcharge instruction drive pulse Pkj has degraded to the predetermined energy, the control circuit 104 determines that the secondary battery 111 is outside the appropriate charge region, that is, in the overcharge region, and performs predetermined control.

The driving pulse P1max with the largest energy among the main driving pulses P1 is a main driving pulse (overdischarge indication driving pulse Pkh) indicating that the secondary battery 111 is overdischarged (that is, the secondary battery 111 is in a state of being charged to a predetermined voltage (for example, the lowest rated voltage required for driving an analog electronic timepiece) or less and outside a suitable charging range). The pulse width of the over-discharge indication drive pulse Pkh is set so that the stepping motor 108 can be rotated because of a large energy when the secondary battery 111 is not over-discharged but is at a voltage higher than the above-mentioned voltage, but the stepping motor 108 cannot be rotated because the energy of the drive pulse is reduced although the pulse width is large when the secondary battery 111 is over-discharged and the voltage is reduced.

When determining that the overdischarge indication drive pulse Pkh has been upgraded to a predetermined energy, the control circuit 104 determines that the secondary battery 111 is in an overdischarge region, which is outside the charge suitable region, and performs predetermined control.

For example, the predetermined voltage, which is the suitable charging range of the secondary battery 111, is set to a rated charging voltage 1.2V to 2.0V defined for the secondary battery 111. In this case, the overcharge-indicating drive pulse Pkj indicates that the secondary battery 111 is charged to 2.0V or more, which is an overcharge region outside the charge suitable region, and the overdischarge-indicating drive pulse Pkh indicates that the secondary battery 111 is lowered to 1.2V or less, which is an overdischarge region outside the charge suitable region.

The secondary battery 111 is configured to supply electric power not only to the stepping motor 108 but also to all circuit elements of the analog electronic timepiece, but may be configured to supply electric power to at least the stepping motor 108.

The oscillation circuit 101 and the frequency dividing circuit 102 constitute a signal generating means, the analog display unit 110 constitutes a display means, and the rotation detecting circuit 109 constitutes a rotation detecting means. The solar cell 112 constitutes a power generation unit that generates electric power and a charging unit that charges the secondary battery 111. The main drive pulse generating circuit 105 and the correction drive pulse generating circuit 106 constitute a drive pulse generating unit. The oscillation circuit 101, the frequency dividing circuit 102, the degradation count circuit 103, the control circuit 104, the main drive pulse generation circuit 105, the correction drive pulse generation circuit 106, and the motor drive circuit 107 constitute control means.

Fig. 2 is a flowchart showing the operation of embodiment 1 of the present invention.

Next, the operation of embodiment 1 of the present invention will be described in detail with reference to fig. 1 and 2.

The solar cell 112 generates power under the control of the control circuit 104, and charges the secondary battery 111. Electric power is supplied from a secondary battery 111 as a power source to a circuit element of an analog electronic timepiece represented by the stepping motor 108, and the analog electronic timepiece operates.

First, an outline of the time display operation in a normal state will be described, and in fig. 1, the oscillation circuit 101 generates a signal of a predetermined frequency, the frequency dividing circuit 102 divides the signal generated by the oscillation circuit 101, generates a clock signal (for example, a signal of a 1-second cycle) serving as a reference for timing, and outputs the clock signal to the degradation count circuit 103 and the control circuit 104.

The control circuit 104 outputs a main drive pulse control signal to the main drive pulse generating circuit 105 at a predetermined cycle in response to the clock signal to drive the stepping motor 108 to rotate.

The main drive pulse generation circuit 105 outputs a main drive pulse P1 of an energy level corresponding to the main drive pulse control signal from the control circuit 104 to the motor drive circuit 107. The motor drive circuit 107 rotationally drives the stepping motor 108 by the main drive pulse P1. The main drive pulse P1 rotationally drives the stepping motor 108 to rotate the time hand of the analog display unit 110. Thus, when the stepping motor 108 has rotated normally, the current time display by the time hand or the like is performed on the analog display unit 110.

The degradation count circuit 103 counts the clock signal from the frequency divider circuit 102, performs a clocking operation, and outputs a degradation signal for degrading the main drive pulse P1 to the main drive pulse generation circuit 105 at a predetermined cycle (for example, 80-second cycle).

The main drive pulse generating circuit 105 changes the energy level to the main drive pulse P1 whose energy level is lowered by one step in response to the degradation signal, and outputs the changed pulse to the motor driving circuit 107. The motor drive circuit 107 drives the stepping motor 108 by the main drive pulse P1 after the step down.

The rotation detection circuit 109 detects the induced signal VRs generated due to the free vibration of the stepping motor 108 in the rotation detection section immediately after the completion of the driving of the stepping motor 108 with the main drive pulse P1, thereby detecting the rotation condition of the stepping motor 108. The rotation detection circuit 109 outputs a 1 st detection signal indicating that the stepping motor 108 has rotated (in other words, the energy of the main drive pulse P1 is sufficient) when the sense signal VRs exceeds the predetermined reference threshold voltage Vcomp, and the rotation detection circuit 109 outputs a 2 nd detection signal indicating that the stepping motor 108 has not rotated (in other words, the energy of the main drive pulse P1 is insufficient) when the sense signal VRs does not exceed the reference threshold voltage Vcomp.

When the rotation detection circuit 109 detects that the stepping motor 108 is not rotating, that is, when the 2 nd detection signal is received from the rotation detection circuit 109, the control circuit 104 outputs a correction drive pulse control signal to the correction drive pulse generation circuit 106. The correction drive pulse generating circuit 106 forcibly rotates the stepping motor 108 with the correction drive pulse P2 through the motor driver 107 in response to the correction drive pulse control signal.

When receiving the 2 nd detection signal, the control circuit 104 controls the main drive pulse generation circuit 105 to output a main drive pulse control signal to increase the level of the main drive pulse P1 by one step in the next driving.

The main drive pulse generating circuit 105 drives the stepping motor 108 with the main drive pulse P1 of which the level of energy is raised by one step in response to the control signal at the time of the next driving. Thereby, the stepping motor 108 is driven by the main drive pulse P1 having the larger energy level.

Next, operations including an excessive power consumption operation when the secondary battery 111 is overcharged will be described with reference to fig. 2.

After the degradation count circuit 103 counts the clock signal from the frequency divider circuit 102 once (step S201), the control circuit 104 determines whether or not a predetermined time (80 seconds in the present embodiment) has elapsed, that is, whether or not the degradation count circuit 103 has counted for a predetermined time, that is, 80 seconds (step S202).

If it is determined in step S202 that the predetermined time has not elapsed, the control circuit 104 outputs a main drive pulse control signal to the main drive pulse generation circuit 105 so that the stepping motor 108 is driven to rotate by the main drive pulse P1 (step S204) when the main drive pulse P1 driven this time is not a drive pulse indicating that the voltage of the secondary battery 111 is at the energy level in the overcharge region (the main drive pulse P1 at the minimum energy level, that is, the overcharge instruction drive pulse Pkj) (step S203). The main drive pulse generating circuit 105 drives the stepping motor 108 to rotate by the main drive pulse P1 through the motor drive circuit 107 in response to the main drive pulse control signal.

The rotation detection circuit 109 detects the rotation state of the stepping motor 108 by the driving based on the main drive pulse P1, and outputs a corresponding detection signal to the control circuit 104. When it is determined that the stepping motor 108 has rotated based on the detection signal, the control circuit 104 ends the process (step S205). The control circuit 104 controls the stepping motor 108 to be driven to rotate by the main drive pulse P1 at the time of the next driving.

When it is determined that the stepping motor 108 is not rotated based on the detection signal (step S205), the control circuit 104 outputs a correction drive pulse control signal to the correction drive pulse generation circuit 106 so that the stepping motor 108 is driven to rotate by the correction drive pulse P2 (step S209), and then raises the level of the main drive pulse P1 by one step to end the process (step S210). The correction drive pulse generating circuit 106 forcibly rotates the stepping motor 108 with the correction drive pulse P2 by the motor drive circuit 107 in response to the correction drive pulse control signal. Thereby, the stepping motor 108 rotates. The next driving is performed by the main drive pulse P1 having a level one step larger than the main drive pulse P1.

When the main drive pulse P1 driven this time in step S203 is the overcharge-indicating drive pulse Pkj, the control circuit 104 outputs a main drive pulse control signal to the main drive pulse generation circuit 105 so that the stepping motor 108 is driven to rotate by the over-consumption drive pulse Pks (the main drive pulse P1 having the maximum energy in the present embodiment 1, i.e., the main drive pulse P1max) having a predetermined energy larger than the overcharge-indicating drive pulse Pkj (step S208).

The main drive pulse generating circuit 105 drives the stepping motor 108 to rotate by the motor drive circuit 107 using an overconsumption drive pulse Pks having a predetermined energy greater than the overcharge indication drive pulse Pkj in response to the main drive pulse control signal. As a result, since a large amount of energy is consumed, the amount of charge in the secondary battery 111 can be rapidly reduced, and the secondary battery can be brought from the overcharged region to an appropriate charged region.

The control circuit 104 performs control in step S208 so that the stepping motor 108 is driven to rotate by the over-consumption drive pulse Pks, and then drives the next holding state by the over-charge instruction drive pulse Pkj, ending the process. When the next driving is performed, the control circuit 104 proceeds to the process of step 203, and the state is maintained in the previous process, and the driving is performed by the overcharge instruction driving pulse Pkj, and therefore, it is determined in step S203 of the current process that the main driving pulse P1 to be driven is the overcharge instruction driving pulse Pkj, and the control is performed in the same manner as the previous process, so that the stepping motor 108 is driven to rotate by the overconsumption driving pulse Pks. Thereafter, the above-described process is repeated.

When it is determined in step S202 that the predetermined time has elapsed, if the main drive pulse P1 driven this time is a drive pulse (overcharge instruction drive pulse Pkj) indicating an energy level in the overcharge region, the control circuit 104 proceeds to step S204 and outputs a control signal to the main drive pulse generating circuit 105 so that the stepping motor 108 is driven by the overcharge instruction drive pulse Pkj (step S206).

In this case, the stepping motor 108 is driven to rotate by the overcharge-indicating drive pulse Pkj (step S204), and driving and upgrading based on the correction drive pulse P2 are performed according to the rotation condition (steps S205, S209, S210). Thus, when the main drive pulse is the overcharge instruction drive pulse Pkj, the drive is performed by the overconsumption drive pulse Pks before a predetermined time (80 seconds in the present embodiment 1) elapses (steps S202, S203, S208), and the drive is performed by the overcharge instruction drive pulse Pkj after the predetermined time elapses (steps S202, S206, S204).

In the case where the main drive pulse P1 driven this time is not the overcharge-indicating drive pulse Pkj in the processing step S206, the control circuit 104 lowers the level of the main drive pulse by one step (step S207), and then proceeds to the processing step S204.

When determining that the stepping motor 108 is not rotating (step S205), the control circuit 104 outputs a correction drive pulse control signal to the correction drive pulse generation circuit 106 so that the stepping motor 108 is driven to rotate by the correction drive pulse P2 (step S209), and then raises the level of the main drive pulse P1 by one step to end the process (step S210). This time of driving is driven by the main drive pulse P1 having a level one step larger than the main drive pulse P1. When the current driving is the overcharge instruction driving pulse Pkj, the next driving is performed by the main driving pulse P1 having a level one step higher than the overcharge instruction driving pulse Pkj.

Therefore, every time the stepping motor 108 is driven for a predetermined time (in other words, a predetermined number of times) by the overconsumption drive pulse Pks, the stepping motor is driven by the overcharge indication drive pulse Pkj, and when the stepping motor 108 cannot be rotated by the overcharge indication drive pulse Pkj, the level of the main drive pulse P1 is increased, and the stepping motor is driven by the main drive pulse P1 other than the overconsumption drive pulse Pks.

As described above, the present embodiment 1 is characterized by including: a battery 111 as a power source that supplies at least the stepping motor 108 with electric power; a rotation detection circuit 109 that detects the rotation state of the stepping motor 108; and a control unit that selects a drive pulse having an energy corresponding to a rotation state of the stepping motor 108 from a plurality of types of drive pulses and drives the stepping motor 108, wherein the control unit performs a predetermined operation corresponding to a voltage of the secondary battery 111 when it is determined that the voltage of the secondary battery 111 is outside the suitable charging range.

Further, embodiment 1 is characterized by including: a battery 111 as a power source that supplies at least the stepping motor 108 with electric power; a rotation detection circuit 109 that detects the rotation state of the stepping motor 108; a control unit that selects and drives the driving pulses P1 and P2 having energy corresponding to the rotation state of the stepping motor 108 from among the plurality of types of driving pulses P1 and P2; and a charging unit that charges the secondary battery 111, wherein the control unit changes the drive to the over-consumption drive pulse Pks having the predetermined energy larger than the over-charge indication drive pulse Pkj and drives the stepping motor 108 when it is determined that the stepping motor 108 can be rotated by the over-charge indication drive pulse Pkj having the predetermined energy among the plurality of types of drive pulses P1 and P2.

Therefore, it is possible to detect that the secondary battery 111 is out of the appropriate charging region without designing a circuit dedicated to voltage detection such as a comparator circuit, and to perform an operation according to the detection result.

When the stepping motor 108 can be driven by the overcharge instruction drive pulse Pkj in this way, it is determined that the secondary battery 111 is overcharged, and the driving is performed by a drive pulse having energy larger than energy required for the stepping motor 108 to rotate, so that the power consumption is excessively large, and the amount of charge in the secondary battery 111 is rapidly reduced without being overcharged, and therefore, it is not necessary to design a circuit dedicated to voltage detection such as a comparator circuit, and it is possible to suppress overcharging of the secondary battery 111 and further to suppress deterioration of the secondary battery 111.

Further, although the overcharge-indicating drive pulse Pkj and the overconsumption drive pulse Pks are drive pulses for normally driving the stepping motor 108, and thus the drive pulse type does not need to be increased, the overcharge-indicating drive pulse Pkj dedicated to overcharge determination and the overconsumption drive pulse Pks dedicated to overconsumption may be used.

Further, the stepping motor 108 can be rotated by the over consumption drive pulse Pks to consume a large amount of power.

Further, according to embodiment 1, since overcharge of the secondary battery 111 can be suppressed without designing a circuit dedicated to voltage detection such as a comparator circuit, the circuit configuration can be reduced in size, and a small analog electronic timepiece can be configured.

If the drive pulse is returned to the overcharge instruction drive pulse Pkj at fixed time intervals and it is determined that the stepping motor 108 is not rotating during the drive by the overcharge instruction drive pulse Pkj, it is determined that the drive pulse is not in the overcharge region, and therefore it is possible to reliably determine whether the secondary battery 111 is in the overcharge region.

Fig. 3 is a flowchart showing the operation of embodiment 2 of the present invention. The block diagram of embodiment 2 is the same as that of fig. 1.

In the above embodiment 1, when the stepping motor 108 can be rotated by the overcharge instruction drive pulse Pkj, it is determined that the secondary battery 111 is overcharged, and the stepping motor 108 is driven by the main drive pulse P1max having the maximum energy which is the overconsumption drive pulse Pks, thereby preventing the overcharge; in embodiment 2, when it is determined that the secondary battery 111 is overcharged as described above, the correction drive pulse P2 is used as the over-consumption drive pulse Pks to perform driving.

That is, in the case where the main drive pulse P1 driven this time in the processing step S203 in fig. 3 is the overcharge-indicating drive pulse Pkj, the control circuit 104 outputs the correction drive pulse control signal to the correction drive pulse generating circuit 106 so that the stepping motor 108 is driven to rotate by the over-consumption drive pulse Pks (the correction drive pulse P2 in the present embodiment 2) having a predetermined energy larger than the overcharge-indicating drive pulse Pkj (step S301).

The correction drive pulse generating circuit 106 drives the stepping motor 108 to rotate by the motor drive circuit 107 using an over-consumption drive pulse Pks (in the present embodiment, the correction drive pulse P2) of a predetermined energy which is larger than the overcharge-indicating drive pulse Pkj in response to the correction drive pulse control signal. As a result, since a large amount of energy is consumed, the amount of charge in the secondary battery 111 can be rapidly reduced, and the secondary battery can be brought from the overcharged region to an appropriate charged region. Further, since the excessive consumption drive pulse Pks having energy larger than that of the embodiment 1 is used, the overcharge suppressing effect is increased.

Fig. 4 is a flowchart showing the operation of embodiment 3 of the present invention. The block diagram of embodiment 3 is the same as that of fig. 1.

As described above, in the embodiments 1 and 2, when it is determined that the secondary battery 111 is overcharged, the single main drive pulse P1max or the correction drive pulse P2 is used as the over-consumption drive pulse Pks, and in the present embodiment, the main drive pulse P1max or the correction drive pulse P2 is used in combination with a plurality of drive pulses, so that a large amount of power is consumed to suppress the overcharge.

That is, the control circuit 104 drives the stepping motor 108 by the main drive pulse P1 in the processing step S204 of fig. 4, and then drives the stepping motor by the correction drive pulse P2 having the same polarity as that of the main drive pulse P1 when the main drive pulse P1 is the overcharge-indicating drive pulse Pkj (steps S205, S401, and S402). In this way, when the main drive pulse P1 is the overcharge indication drive pulse Pkj indicating overcharge, the main drive pulse P1 is driven by the correction drive pulse P2 in addition to the overcharge indication drive pulse Pkj (steps S204 and S402).

In this way, since the excessive consumption drive pulse Pks is formed by a combination of a plurality of types of drive pulses (in embodiment 3, the overcharge-indicating drive pulse Pkj and the correction drive pulse P2), it is possible to consume a large amount of energy, rapidly reduce the amount of electricity stored in the secondary battery 111, and enter an appropriate charge range from an overcharge range, as in embodiments 1 and 2. Further, since the stepping motor 108 is rotated by the overcharge instruction drive pulse Pkj at the time of the first drive, and a large amount of power can be consumed without rotating the stepping motor 108 by the subsequent correction drive pulse P2 of the same polarity, the roles of the respective drive pulses are clearly shared, and the control can be easily performed.

Fig. 5 is a flowchart showing the operation of embodiment 4 of the present invention. The same reference numerals are given to the parts subjected to the same processing as in fig. 2 to 4. The block diagram of embodiment 4 is the same as that of fig. 1.

The above-described 1 st to 3 rd embodiments are examples when the secondary battery 111 enters the overcharge region, and the present 4 th embodiment is an example when the secondary battery 111 enters the overdischarge region, and the present 4 th embodiment can be combined with the above-described 1 st to 3 rd embodiments.

In fig. 1 and 5, when it is determined in the processing step S202 that the predetermined time has not elapsed, the control circuit 104 outputs a main drive pulse control signal to the main drive pulse generation circuit 105 so that the stepping motor 108 is driven to rotate by the main drive pulse P1 (step S204) when the main drive pulse P1 driven this time is not a drive pulse (the overdischarge indication drive pulse Pkh (the main drive pulse P1max at the maximum energy level in the present embodiment 4)) indicating that the voltage of the secondary battery 111 is at the predetermined energy level in the overdischarge region (step S203). The main drive pulse generating circuit 105 drives the stepping motor 108 to rotate by the main drive pulse P1 through the motor drive circuit 107 in response to the main drive pulse control signal.

When it is determined in step S203 that the main drive pulse P1 driven this time is the overdischarge-indicating drive pulse Pkh of the predetermined energy, the control circuit 104 determines that the secondary battery 111 is in the overdischarge region, and controls the time hand to rotate the stepping motor 108 by the main drive pulse P1max of the maximum energy level so that the time hand performs an irregular operation (the driving of the stepping motor 108 at this time is referred to as an irregular driving) different from the regular operation (the driving of the stepping motor 108 at this time is referred to as a regular driving) (step S501).

The drive pulse used in step S501 is a drive pulse equal to or larger than the overdischarge indication drive pulse Pkh so that the stepping motor can be rotated more reliably, and may be a drive pulse equal to or larger than the overdischarge indication drive pulse Pkh, and may be a main drive pulse P1max having the maximum energy, the correction drive pulse P2, or a specific drive pulse.

The normal drive is an operation of driving the stepping motor 108 once every time a predetermined time elapses, and is an operation of driving the stepping motor 108 to rotate so that, for example, a second hand, which is a time hand for displaying time, is moved 1 time every 1 second. The irregular driving is an operation of rotationally driving the stepping motor 108 in a manner different from the above-described ordinary driving. For example, the stepping motor is driven a plurality of times within a predetermined time every time the predetermined time elapses. For example, in the case of normal driving, the second hand is operated 1 time per 1 second, and in the case of non-normal driving, the second hand is operated 2 times per 2 seconds.

After performing the control of the irregular driving in step S501, the control circuit 104 holds the state for the next time and drives the over-discharge instruction driving pulse Pkh, and ends the processing. When the control circuit 104 proceeds to the process of step 203 at the time of the next driving, since the state is maintained in the previous process to perform the driving by the overdischarge-indicating drive pulse Pkh, the main drive pulse P1 determined to be the overdischarge-indicating drive pulse Pkh at the process of this time of step S203 is controlled in the same manner as the previous time so that the stepping motor 108 is irregularly driven (step S501). Thereafter, the above-described process is repeated.

The control circuit 104 changes the main drive pulse P1 to the main drive pulse P1 smaller than the overdischarge indication drive pulse Pkh by a predetermined level (one level in the present embodiment) at predetermined time intervals (80 seconds in the present embodiment) and drives the same (steps S202, S207, and S204). When the stepping motor 108 can be rotated by the main drive pulse P1, the control circuit 104 determines that the secondary battery 111 is not in the overdischarge area, and drives the stepping motor by the main drive pulse P1 while keeping the state in the next driving (step S205). Thereby, the next irregular driving is stopped.

As described above, according to embodiment 4, when it is determined that the overdischarge indication drive pulse Pkh has been upgraded to a predetermined energy, the control circuit 104 determines that the secondary battery 111 is in the overdischarge region and drives the stepping motor 108 to rotate by the irregular driving different from the normal driving, and thus the user can be urged to charge the secondary battery 111 without designing a dedicated circuit or the like for detecting the voltage of the secondary battery.

In addition, although the energy level is changed by changing the pulse width using the main drive pulse P1 of the rectangular wave in each of the above embodiments, the pulse width may be fixed by using the main drive pulse of the comb teeth shape, the drive energy may be changed by changing the duty ratio, the duty ratio may be fixed, the drive energy may be changed by changing the number of teeth of the comb (the pulse width is changed in this case), or the drive energy may be changed by changing the pulse voltage or the like.

Further, as the charging unit of the secondary battery 111, a structure is adopted in which the solar battery 112 is built, but a configuration may be adopted in which a charging unit other than the solar battery 112, such as an automatic winding-up or manual winding-up charging unit, is adopted, or a configuration may be adopted in which a charging unit separate from the analog electronic timepiece is adopted.

Further, it can be applied to a stepping motor that drives components other than the time hand and the calendar.

Further, although an example of an electronic timepiece has been described as an example of application of a stepping motor, the present invention can also be applied to an electronic device using a motor.

Industrial applicability

The stepping motor control circuit of the present invention can be applied to various electronic apparatuses using a stepping motor.

The electronic timepiece of the present invention is applicable to various analog electronic timepieces with a calendar function, such as an analog electronic timepiece with a calendar function and an analog electronic timepiece with a calendar function.

Claims (13)

1. A stepping motor control circuit, comprising:

a secondary battery as a power source that supplies at least electric power to the stepping motor;

a rotation detection unit that detects a rotation condition of the stepping motor; and

a control unit for selecting a drive pulse having an energy corresponding to a rotation state of the stepping motor from a plurality of types of drive pulses and driving the stepping motor,

the control unit performs a predetermined operation corresponding to the voltage of the secondary battery when it is determined that the voltage of the secondary battery is outside the suitable charging range.

2. The stepping motor control circuit according to claim 1, wherein the control means determines that the secondary battery is in an overcharged region and changes the drive to an over-consumption drive pulse having energy larger than that of the overcharge-indicating drive pulse, when it is determined that the stepping motor can be rotated by the overcharge-indicating drive pulse having predetermined energy.

3. The stepping motor control circuit according to claim 2,

as the plurality of types of drive pulses, a plurality of types of main drive pulses having different energies from each other and a correction drive pulse having a larger energy than each of the main drive pulses are prepared,

the overcharge-indicating drive pulse is a main drive pulse having the lowest energy among the plurality of kinds of main drive pulses.

4. The stepping motor control circuit according to claim 2,

as the plurality of types of drive pulses, a plurality of types of main drive pulses having different energies from each other and a correction drive pulse having a larger energy than each of the main drive pulses are prepared,

the over-consumption driving pulse is the main driving pulse with the largest energy among the plurality of kinds of main driving pulses.

5. The stepping motor control circuit according to claim 2,

as the plurality of types of drive pulses, a plurality of types of main drive pulses having different energies from each other and a correction drive pulse having a larger energy than each of the main drive pulses are prepared,

the over-consumption driving pulse is the correction driving pulse.

6. The stepping motor control circuit according to claim 2,

as the plurality of types of drive pulses, a plurality of types of main drive pulses having different energies from each other and a correction drive pulse having a larger energy than each of the main drive pulses are prepared,

the over-consumption drive pulse is a drive pulse obtained by combining an over-charge indication drive pulse and a correction drive pulse.

7. The stepping motor control circuit according to claim 2, wherein the control means changes the main drive pulse to the overcharge-indicating drive pulse at predetermined time intervals, and changes the main drive pulse to a main drive pulse other than the overconsumption drive pulse to drive when the stepping motor cannot be rotated by the overcharge-indicating drive pulse.

8. The stepping motor control circuit according to claim 1, wherein the control unit determines that the secondary battery is in an overdischarge region in a case where it is determined that an overdischarge-indicating drive pulse has been upgraded to a predetermined energy, and drives the stepping motor to rotate by irregular driving different from normal driving.

9. The stepping motor control circuit according to claim 8,

as the plurality of types of drive pulses, a plurality of types of main drive pulses having different energies from each other and a correction drive pulse having a larger energy than each of the main drive pulses are prepared,

the overdischarge-indicating drive pulse is a main drive pulse having the largest energy among the plurality of kinds of main drive pulses.

10. The stepping motor control circuit according to claim 8, wherein the control unit drives the stepping motor once every time a predetermined time elapses in the normal driving, and drives the stepping motor a plurality of times every time a predetermined time elapses in the irregular driving.

11. The stepping motor control circuit according to claim 8, wherein the control unit changes a main drive pulse from a main drive pulse to a main drive pulse smaller than the overdischarge indication drive pulse by a predetermined level at predetermined time intervals, determines that the secondary battery is not in an overdischarge area when the stepping motor can be rotated by the main drive pulse, and stops the irregular drive.

12. The stepping motor control circuit according to claim 1, wherein the stepping motor control circuit has a charging unit that charges the secondary battery.

13. An analog electronic timepiece having a stepping motor that drives a time hand to rotate, and a control unit that controls the stepping motor,

as a control unit for controlling the stepping motor, the stepping motor control circuit according to claim 1 is used.