JPS6123516B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timepiece, and more particularly to an improvement in a drive circuit 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 converters used in wristwatches have problems with stability against equilibrium loads.However, in order to improve shock resistance, the balance drive system uses single-phase pulses, and in order to improve shock resistance, the drive pulses are controlled by the induced voltage of the drive coil. A method for controlling the pulse width has 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 wide at the time of impact, malfunctions are likely to occur, and multi-phase pulse motors In this case, the structure is multi-polar and the rotation angle of one step becomes small, so the induced voltage becomes small and it is not possible to perform a sufficient control action, resulting in poor stability. From these viewpoints, since stability is obtained by supplying pulses with the maximum pulse width, the power consumption is also increased.

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 power 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 example 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, 109 is a drive coil, a,
b is the drive coil terminal, and it is a pulse motor that rotates the rotor in a fixed direction in steps by guiding the magnetic flux generated in the drive coil to the stator due to the current due to the two-phase pulse voltage applied to a and b. be.

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 when a balance wheel is used as an electromechanical converter, Figure 5 is the state at steady state, and Figure 6 is the state at the time of impact. shows. 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.
1, and short pulses φ ₁ and φ ₂ are alternately generated at each output F ₁ and F ₂ .
F ₁ is reset, set flip-flop 126
(hereinafter referred to as RS-FF) _R4 terminal, return means 2
The S ₆ terminal and F ₂ of the RS-FF 127 constituting the RS-FF 10 are connected to the S ₄ terminal of the RS-FF 126 and the S ₅ terminal of the RS-FF 128 which is the recovery 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 of the drive circuit 204.
(hereinafter referred to as P-ChMOS transistor), FF1
The other output ₂ of 21 is the other input of FF123 and P
- Connected to each gate of the ChMOS transistor 135, output F ₃ of the FF 123 N-channel MOS transistor 136, (hereinafter referred to as N-ChMOS transistor) ₃ is the N-ChMOS transistor 13
It is connected to each gate of 4. Drive coil 13
7 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, the b terminal is connected to each input gate of the induced voltage detection inverter 129,
The output of the inverter 129 is connected to the _R6 terminal of the FF 127 of the return means 210 via the gate circuit 131.
The inverter 130 output is connected to the _R5 terminal of the FF 128 via a gate circuit 132. Said
The FF127 output _F6 is the switching circuit 125 of the pulse selection circuit 206, and the FF128 output _F5 is the switching circuit 124.
connected to each input.

First, considering the case of a balance wheel, in Fig. 5, a _φ1 pulse is generated at t=t, and P-Ch, MOS
Transistor 133 is turned on. At this time F ₃
= 1, so N-ChMOS transistor 136
is on, the drive circuit is in the state shown in FIG. 4(1), a drive voltage is applied to the a terminal, a current flows from a to b, and the balance receives a driving 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 f=1. t= _t2
When the pulse is cut off, F ₃ = 0, ₃ = 1, and P-
ChMOS transistor 133N-ChMOS transistor 136 is turned off, 134 is turned on, and the fourth
It will look like Figure (2). The a terminal is the transistor 134
Since the inverter 13 for detecting the induced voltage of the detection circuit 209 is grounded as shown in FIG.
0 does not work. On the other hand, the b terminal is grounded when the _φ1 pulse is applied, but immediately after the pulse is cut off, the grounding is released and an induced voltage is applied to the inverter 129. At t= _t3 to _t4 , the induced voltage is The voltage exceeds the threshold voltage, and the output d of the gate circuit 131 is generated. The gate circuits 131 and 132 are connected to the induced voltage detection inverter 12 of the detection circuit 209.
This is for using only the induced voltage, excluding the drive pulses detected by FFs 9 and 130, as the reset input for the FFs 127 and 128 of the recovery means 210.

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= _t5 , a _φ2 pulse is generated, and P-
ChMOS transistor 135 is turned on. N-
Since the ChMOS transistor 134 remains on, the drive circuit 204 is in the state shown in FIG. 4(3),
A driving voltage is applied to the b 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
Therefore, P-ChMOS transistor 135, N-
The ChMOS transistor 134 is turned off and the ChMOS transistor 136 is turned on, as shown in FIG. 4(4). Since the b terminal is grounded through the transistor 136, as shown in FIG. 5b, the induced voltage detection inverter 129
doesn't work. On the other hand, the a terminal is grounded when the _φ2 pulse is applied. Immediately after the pulse ends, the ground is released and an induced voltage is applied to the inverter 130, and at t= _t7 to _t8 , the induced voltage becomes equal to or higher than the threshold voltage of the inverter, and a gate circuit output C is generated. FF128 is reset by C and e=0, and the switching circuit 124 output becomes the FF117 output.
The next φ ₁ is a short pulse width and FF
127 is set at _φ1 and reset at d=
0, the output of the switching circuit 125 becomes the output of the FF 117, and the next _φ2 becomes a pulse with a short pulse width.

Next, when an impact load is applied, the result will be as shown in FIG. That is, the FF127 output f is set to 1 at φ ₁ , but since the induced voltage decreases and becomes below the threshold voltage, no set pulse is generated, so it becomes =1.
remains as it is, and the switching circuit 125 switches FF12.
FF118 output is applied to the _R2 terminal of 1, and _φ2
becomes twice the pulse width _t13 to _t14 . Furthermore FF12
8 is set to 1 by _φ2 , but since a reset pulse is not generated, e remains at 1, and the switching circuit 124 switches and the _R1 terminal of FF120 is set to FF11.
8 outputs are applied, the next φ ₁ is twice the pulse width
It becomes _t15 to _t16 . When the pulse width doubles, the driving force increases, and the induced voltage returns to its previous state, t=t ₁₇
At ~ _t18 , a reset pulse is generated at d, which becomes =0, and the next _φ2 pulse returns to the previous state, and furthermore, the _φ1 pulse also returns to the previous state.

Next, consider the case of a pulse motor. The induced voltage waveform is slightly different, but 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 FF1 of the return means 210.
Applied to the set terminal _S6 of 27, the FF output is =
Return to 1. Immediately after _φ1 is cut off, the a terminal is grounded, the b terminal is ungrounded, and the induced voltage accompanying the rotor's free decay is applied to the detection inverter 129 of the detection circuit 209, and the induced voltage is induced at t= _t33 to _t34 . When the voltage exceeds the threshold voltage of the detection inverter, a gate circuit output d is generated. The FF127 output is reset to 0 and the next _φ2 is 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 FF1 of the return means 210.
28 set terminal _S5 , the FF output is e=
Return to 1. When the pulse ends at t=t ₃₇ , the b terminal is grounded, the a terminal is ungrounded, the induced voltage is applied to the detection inverter 130, and t=t ₃₈
At ~ _t39 , the induced voltage becomes equal to or higher than the threshold voltage of the detection inverter, and gate circuit output c is generated.
FF128 is reset at c and e=0, and the switching circuit 124 output becomes the FF117 output and the next φ
₁ becomes a pulse with a short pulse width, FF127 is set at _φ1 , reset at d, becomes 0, and the output of the switching circuit 125 becomes the output of FF117, 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 and becomes below the threshold voltage of the detection inverter of the detection circuit 209, causing the reset pulse d.
Since no longer occurs, it remains set to 1, the switching circuit 125 switches, and the FF 121
The FF118 output is applied to the _R2 terminal, and φ2 is ₂
The pulse width is doubled from t ₄₃ to _{t 44} . Furthermore, the FF 128 is set by φ ₂ and becomes e=1, the induced voltage decreases and becomes below the threshold voltage of the detection inverter 130, and the reset pulse c is no longer generated, so e=1 remains set and the switching is performed. The circuit 124 is switched and the output of the FF 118 is applied to the R ₁ terminal of the FF 120, and φ ₁ becomes twice the pulse width and the driving force increases, thereby preventing malfunction. load is 0
When the voltage 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 one 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 Examples are suitable. As in the present application, the transistors of the pulse motor drive circuit are configured to be independently controlled to detect the state of the load, and one end of the drive coil is disconnected from the power supply line by the transistor when the rotor freely damps vibrations. According to
Since the induced voltage is detected with a large amplitude, the detection circuit is simplified, and it is now possible to accurately detect the load condition of a pulse motor, which has been difficult in the past.

If configured as in the present application, the converter will be driven with a drive pulse of 5 milliseconds or less, which is the minimum pulse required to drive the converter, during normal operation, and when an impact load is applied, the converter will be driven with a drive pulse of 5 milliseconds or less.
By increasing the pulse width to 5 milliseconds or more, we can provide the converter with driving force to overcome the impact and prevent malfunctions, and once the shock load is removed, by reducing the pulse width to the original 5 milliseconds or less, the average Current consumption 1μA
It is possible to do the following.

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, although the present embodiment has been described with respect to the drive pulse at the time of an impact, it is obvious that the present invention can also be applied to a case where there is a load fluctuation, 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-
ChMOS transistor, 134, 136...N
- ChMOS transistor, 137... Drive coil, 205... Detection storage circuit, 209... Detection circuit, 210... Recovery circuit, 129, 130... Detection inverter, 131, 132... Gate circuit.

Claims (1)

[Claims] 1. A pulse motor including an oscillation circuit, a frequency dividing circuit, a pulse motor drive circuit, a drive coil, and a rotor,
a detection circuit that detects an induced voltage generated in a drive coil due to free damping vibration of the rotor after the application of drive pulses to the pulse motor ends; a pulse conversion circuit that generates a plurality of drive pulses with different drive forces; In an electronic timepiece that is controlled by the detection circuit and includes a pulse selection circuit for selectively supplying output pulses of the pulse conversion circuit to the pulse motor drive circuit, the pulse motor drive circuit has a plurality of independently controlled pulse motor drive circuits. 1. An electronic timepiece comprising a control circuit configured of MOS transistors and controlling each MOS transistor constituting the pulse motor drive circuit to substantially disconnect at least one end of the drive coil from a power supply line.