JPS6130224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timepiece, and more particularly to a drive system for a pulse motor, which is an electromechanical converter thereof.

BACKGROUND ART Electromechanical converters used in electronic watches include a balance that is forcibly driven by a frequency-divided signal from a crystal oscillator, a pulse motor that rotates one step at a time in a fixed direction, and the like.

Generally, electromechanical transducers used in wristwatches have a problem with stability against shock loads. However, in order to improve the shock resistance of the balance drive system using single-phase pulses, the pulse width of the drive pulse is increased by the induced voltage in the drive coil. Methods for controlling this have been proposed and some have been put into practical use.

However, in the case of a single-phase drive system, in the case of a balance wheel, the drive pulse is only applied to one side of the reciprocating motion, so even if the pulse width becomes shockingly wide, malfunctions are likely to occur, and multi-phase pulses In the case of a motor, the motor has a multipolar structure and the rotation angle of one step becomes small, so the induced voltage becomes small and a sufficient control action cannot be performed, resulting in poor stability. From these points of view, stability is obtained by supplying pulses with the maximum pulse width, which has the disadvantage of increasing power consumption.

The present invention provides a highly stable converter drive circuit with good shock resistance and without the above-mentioned drawbacks.

The present invention provides a highly stable electric watch characterized in that the pulse width of the drive pulse of an electromechanical converter driven by two-phase drive pulses is controlled in a stepwise manner by the induced voltage of the drive coil. The purpose of this invention is to provide a drive circuit for a mechanical converter.

Another object of the present invention is to provide an electromechanical converter drive circuit for a watch, which is characterized by having an inverter having one end of the drive coil as an input, and an inverter having the other end as an input.

Examples will be described below.

Figures 1a and 1b show an embodiment of an electromechanical converter, in which 101 is a balance wheel, 102 is a magnet, 103, 1
04 is a drive coil, 105 is a balance spring, a,
b is a drive coil terminal, and the magnet fixed to the balance wheel receives a force due to the magnetic field generated in the drive coil due to the current caused by the two-phase pulse voltage applied to a and b, and the balance consisting of the hairspring and balance wheel is performs a reciprocating motion. FIG. 2 shows another embodiment of the electromechanical converter, in which 106 is a rotor made of a magnet having at least two magnetic poles, 107 and 108 are stators made of magnetic material, and 109 is a driving coil, a, b.
is a drive coil terminal, and it is a pulse motor that rotates the rotor in a fixed direction in a step manner by guiding the magnetic flux generated in the drive coil to the stator due to the current caused by the two-phase pulse voltage applied to a and b. .

FIG. 3 shows an embodiment of the electronic watch of the present invention, with 20
1 is a crystal oscillation circuit, 202 is a frequency dividing circuit, 203 is a pulse selection circuit 206, a pulse conversion circuit 207,
Pulse width switching circuit 204 including control circuit 208
205 is a detection storage circuit including a detection circuit 209 and a recovery means 210.

Figure 4 is an explanatory diagram of the state of the drive coil, Figures 5 and 6 are waveform diagrams of various parts when a balance wheel is used as an electromechanical converter, Figure 5 is at steady state, and Figure 6 is at impact. Indicates the status of 7 and 8 are waveform diagrams of various parts when a pulse motor is used as an electromechanical converter, with FIG. 7 showing a steady state and FIG. 8 showing a state at an impact.

In FIG. 3, the outputs of flip-flops (hereinafter referred to as FF) 117 and FF 118 of the frequency dividing circuit 202 are connected to the switching circuits 124 and 12 of the pulse selection circuit 206.
During normal operation, the output of FF117 is input to FF120, 12 of pulse conversion circuit 207.
Short pulse width pulses φ ₁ and φ ₂ are alternately generated at the respective outputs F ₁ and F ₂ . _F1 is the reset, _R4 terminal of the set flip-flop 126 (hereinafter referred to as RS-FF), _S6 terminal of the RS-FF127 constituting the return means 210, _F2 is the _S4 terminal of the RS-FF126, It is connected to the S ₅ terminal of the RS-FF 128, which is the return means 210. The other output ₁ of the FF 120 of the pulse conversion circuit 207 is the input of the FF 123 of the control circuit 208 and the P channel MOS transistor 133 (hereinafter referred to as P-Ch MOS transistor) of the drive circuit 204, and the other output ₂ of the FF 121 is the FF 12
3 other inputs and P-Ch MOS transistor 1
35, and the output F ₃ of FF123
is N-channel MOS transistor 136 (hereinafter referred to as N-Ch MOS transistor) ₃ is N
-Ch Connected to each gate of the MOS transistor 134. The drive coil 137 is connected between the common drains a and b of the MOS transistors, the a terminal is connected to the induced voltage detection inverter 130 of the detection circuit 209, and the b terminal is connected to the induced voltage detection inverter 12.
9 and connected to each input gate of the inverter 12.
9 output is connected to the R ₆ terminal of the FF 127 of the return means 210 via the gate circuit 131 and the inverter 13.
The 0 output is sent to the FF128 via the gate circuit 132.
Connected to _R5 terminal. Said FF127 output _F6
is the switching circuit 125 of the pulse selection circuit 206, FF
128 output F ₅ is connected to each input of switching circuit 124 .

First, considering the case of a balance wheel, in FIG. 5, a _φ1 pulse is generated at t= _t1 , and the P-Ch MOS transistor 133 is turned on. At this time F ₃ =
1, so N-Ch MOS transistor 136
is on, the drive circuit is in the state shown in FIG. 4, a drive voltage is applied to the a terminal, a current flows from a to b, and the balance receives a drive force. On the other hand, the _φ1 pulse is applied to the set terminal _S6 of the FF 127 of the return means 210, and the FF output returns to =1. t= _t2
When the pulse is cut off, F ₃ = 0, ₃ = 1, and P
-Ch MOS transistor 133N-Ch MOS transistor 136 is turned off, 134 is turned on,
It will look like Figure 4 2. A terminal is transistor 1
34, as shown in FIG. 5a, the induced voltage detection inverter 130 of the detection circuit 209 does not operate. On the other hand, the b terminal is grounded when the φ ₁ pulse is applied, but it is ungrounded immediately after the pulse ends, and the induced voltage is transferred to the inverter 129.
The induced voltage becomes higher than the threshold voltage of the inverter at t= _t3 to _t4 , and the gate circuit 131
An output d is generated. Gate circuits 131, 132
The FFs 127 and 1 of the recovery means 210 detect only the induced voltage, excluding the drive pulses detected by the induced voltage detection inverters 129 and 130 of the detection circuit 209.
This is used as a reset input for 28.

This output d is applied to the reset terminal _R6 of the FF127 of the recovery means 210, and the FF127 output=
It becomes 0. Therefore, since the selection gate 125 output of the pulse selection circuit 206 becomes the output of the FF 118,
The next φ ₂ pulse also has the same short pulse width as the φ ₁ pulse.

Next, at t=t ₅ , a φ ₂ pulse is generated, and P-Ch
MOS transistor 135 is turned on. N-Ch
Since the MOS transistor 134 remains on, the drive circuit 204 is in the state shown in FIG.
A driving voltage is applied to the terminal, a current flows from b to a, and the balance receives a driving force in the opposite direction. On the other hand, the _φ2 pulse is applied to the set terminal _S5 of the FF 128 of the return means 210, and the FF output returns to e=1. When the pulse ends at t=t ₆ , F ₃ = 1, ₃
= 0, P-Ch MOS transistor 134
is off and 136 is on, as shown in FIG. Since the b terminal is grounded through the transistor 136, as shown in FIG. 5b, the induced voltage detection inverter 129 does not operate. On the other hand, the a terminal is grounded when the φ pulse is applied, but immediately after the pulse ends, the grounding is released and an induced voltage is applied to the inverter 130, and at t= _t7 to _t8 , the induced voltage reaches the threshold of the inverter. The voltage exceeds the voltage, and gate circuit output C is generated. FF128 is reset by C and e=0, and the switching circuit 124 output becomes FF1.
17 output, and the next φ ₁ becomes a short pulse width pulse, and FF127 is set at φ ₁ , reset at d, and becomes = 0, and the output of the switching circuit 125 becomes
The output is FF117, and the next _φ2 is a pulse with a short pulse width.

Next, when an impact load is applied, the result will be as shown in FIG. In other words, the FF127 output is set to 1 at φ ₁ , but the induced voltage decreases and becomes below the threshold voltage, so no reset pulse is generated =
remains at FF1, and the switching circuit 125 switches to FF1.
The FF118 output is applied to the _R2 terminal of 21, and φ
₂ is twice the pulse width (t ₁₃ to t ₁₄ ). moreover
FF128 is set to 1 by _φ2 , but since a reset pulse is not generated, e=1 remains, the switching circuit 124 switches, and the FF118 output is applied to the _R1 terminal of FF120, and the next _φ1 is set to 2. The pulse width (t ₁₅ to t ₁₆ ) is doubled. When the pulse width doubles, the driving force increases, and the induced voltage returns to the previous state, a reset pulse is generated at d at t = t ₁₇ to _{t 18} , which becomes = 0, and the next φ ₂ returns to the previous state. Then, the _φ1 pulse also returns to the previous state.

Next, consider the case of a pulse motor. The induced voltage waveform is slightly different, and everything else is almost the same as in the case of the balance wheel, but in Fig. 7, t=t ₃₁
A _φ1 pulse is generated, a driving voltage is applied to the a terminal of the driving coil, and a current flows from a to b, and the stator 10
7 and 108 are excited, and the rotor 106 moves to the right.
It rotates 180°, oscillates with free damping for a certain period of time, and then stops. On the other hand, the _φ1 pulse is the FF of the return means 210.
127's set terminal _S6 , the FF output returns to =1. Immediately after _φ1 is disconnected, the a terminal is grounded, the b terminal is ungrounded, and the induced voltage accompanying the free damping vibration of the rotor is applied to the detection inverter 129 of the detection circuit 209, and t=t ₃₃ to _{t 34}
At this point, the induced voltage exceeds the threshold voltage of the detection inverter, and gate circuit output d is generated. FF1
The 27 output is reset to 0 and the next _φ2 has a short pulse width. The rotor becomes almost stationary and stable at t=t ₃₅ . Next, at t=t ₃₆ , a φ ₂ pulse is generated, a driving voltage is applied to the b terminal of the driving coil, and a current flows from b to a, and the coil is reversely excited and rotated 180° in the same direction. On the other hand, the _φ2 pulse is the FF of the return means 210.
It is applied to the set terminal _S5 of 128, and the FF output is e.
= returns to 1. When the pulse breaks at t=t ₃₇ , b
The terminal is grounded, the a terminal is ungrounded, the induced voltage is applied to the detection inverter 130, and t=
From _t38 to _t39 , the induced voltage becomes equal to or higher than the threshold voltage of the detection inverter, and the gate circuit output c is generated. FF128 is reset at c, e=0, and the switching circuit 124 output becomes the FF117 output, and the next _φ1 becomes a pulse with a short pulse width, and the FF12
7 is set at _φ1 , reset at d, becomes 0, and the output of the switching circuit 125 becomes the FF117 output, and the next _φ2 becomes a pulse with a short pulse width.

Next, when subjected to impact load, as shown in Figure 8, FF
The 127 output is set to 1 at φ ₁ , but the induced voltage decreases to below the threshold voltage of the detection inverter of the detection circuit 209, and the reset pulse d is no longer generated, so it remains set to 1. , the switching circuit 125 is connected to the switching FF 121.
The FF118 output is applied to the _R2 terminal, and φ2 is ₂
The pulse width (t ₄₃ to t ₄₄ ) is doubled. Furthermore FF12
8 is set by _φ2 and becomes e=1, and as the induced voltage decreases and becomes below the threshold voltage of the detection inverter 130 and the reset pulse c is no longer generated, e=1 remains set and the switching circuit changes. 124 is switched and the R ₁ terminal of FF120 is FF11.
Since 8 outputs are applied, the pulse width of _φ1 is doubled, and the driving force is increased, so that error movement can be prevented. When the load becomes 0, the induced voltage returns to the previous state and a reset pulse is generated at d, which becomes 0, the _φ2 pulse returns to the previous state, and the _φ1 pulse also returns to the previous state. In the case of a balance wheel, the induced voltage is generated just before and after the drive pulse, so either can be used for pulse width control, but in the case of a pulse motor, the induced voltage is only generated immediately after the drive pulse, so this method is not recommended. An example is appropriate.

If configured as in the present application, detecting the load state is purely related to the motion of the rotor that occurs in the drive coil due to the free damping vibration of the rotor after the application of drive pulses to the pulse motor ends. Since only the induced voltage can be measured, detection accuracy is improved, making it possible to accurately detect the load condition of a pulse motor, which was previously considered difficult. During normal operation, the converter is driven with a minimum pulse width of 5 milliseconds or less, and when an impact load is applied, the pulse width is increased to 5 milliseconds or more to provide driving force that overcomes shock. is applied to the converter to prevent malfunction, and if the shock load is eliminated, the average current consumption can be reduced to 1 μA or less by reducing the pulse width to the original 5 milliseconds or less.

In addition, since the induced voltage of the drive coil is detected by a CMOS inverter, there is no need for any detection mechanism such as installing a detection coil in the converter or providing contacts or semiconductors in the wheel train connected to the converter. Since there is no amplification circuit, the current consumption can be ignored. Therefore, it is possible to reduce the total current consumption including the oscillation circuit and the frequency dividing circuit to 2 μA or less.

In this embodiment, the drive pulse width is set to be twice as long as during normal operation when an impact occurs, but it is also possible to set the drive pulse width to an arbitrary pulse width in steps.

Further, in this embodiment, the driving pulse width at the time of impact has been described, but it is obvious that the invention can also be applied to cases where load fluctuation occurs, such as when driving a calendar display, for example.

[Brief explanation of the drawing]

1A and 1B are a plan view and a side view showing an embodiment of a balance wheel which is an electromechanical converter, FIG. 2 is a plan view showing an embodiment of a pulse motor which is an electromechanical converter, and FIG. is a circuit diagram showing one embodiment of the electronic timepiece of the present invention, FIG. 4 is a state explanatory diagram of a drive coil, FIGS. 5 and 6 are waveform diagrams of various parts when a balance wheel is used as an electromechanical converter, FIGS. 7 and 8 are waveform diagrams of various parts when a pulse motor is used. 101... Balance wheel, 102... Magnet, 103,
104, 109... Drive coil, 105... Balance spring, 106... Rotor, 107, 108...
... Stator, 201 ... Oscillation circuit, 110 ... Inverter, 111 ... Crystal resonator, 112 ... Feedback resistor, 113, 114 ... External capacitor, 202 ...
...Frequency dividing circuit, 115...Inverter, 116,
117, 118, 119...flip flop,
203...Pulse width switching circuit, 206...Pulse selection circuit, 207...Pulse conversion circuit, 208...
...Control circuit, 124, 125...Switching circuit, 20
4...Drive circuit, 133, 135...P-Ch
MOS transistor, 134, 136...N-Ch
MOS transistor, 137... Drive coil, 2
05...Detection storage circuit, 209...Detection circuit, 2
10... Recovery circuit, 129, 130... Detection inverter, 131, 132... Gate circuit.

Claims (1)

[Claims] 1. In an electronic watch equipped with a pulse motor including an oscillation circuit, a frequency dividing circuit, a pulse motor drive circuit, a drive coil, and a rotor, the free damping vibration of the rotor after the application of drive pulses to the pulse motor is completed. a detection circuit that detects the induced voltage generated in the drive coil; a pulse conversion circuit that generates a plurality of drive pulses with different driving forces; and a pulse conversion circuit that is controlled by the detection circuit to convert the output pulses of the pulse conversion circuit into pulses. An electronic timepiece characterized by comprising a pulse selection circuit for selectively supplying pulses to a motor drive circuit.