JPH0221293A - Electromagnetic driving circuit - Google Patents

Abstract

PURPOSE:To stabilize a swinging of a pendulum by arranging a coil for detecting and driving a permanent magnet, a variable reference voltage source for generating a reference voltage and a comparator circuit which generates an output when an induced voltage of the coil exceeds the reference voltage. CONSTITUTION:When an induced voltage of a coil LL with a length (a) of an electromagnetically driving circuit exceeds a voltage Vn-1 of a reference voltage source, an output is produced from a comparator circuit CM and in response to the output, a pulse with a specified voltage value is generated for a specified period from a pulse generation circuit PG. Then, counts of a counting circuit CT turn to n+1 by a clock pulse while a reference voltage of the reference voltage source VR shifts to Vn+1. The magnitudes of the reference voltage and the induced voltage are compared and when that of the induced voltage is larger, the reference voltage is raised by one step. When it is smaller, the reference voltage is lowered by one step. Thus, a pendulum is driven on optimum driving conditions thereby stabilizing the swinging of the pendulum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic drive circuit used for driving a pendulum or the like.

[Prior Art] For example, there is a drive circuit shown in FIG. 8 that detects and drives the pendulum of a clock using one coil.

In this circuit, an induced voltage is generated in coil L2 by the passage of a permanent magnet fixed to the pendulum, and when this exceeds a reference voltage, transistor T2 is turned off, transistor T1 is turned on, and a driving current flows through coil L2. . The on time t of this transistor T1 is determined by the time constants of the capacitor C and the resistor R1.

In order to drive the magnet efficiently, it is preferable to drive at the maximum point of the induced voltage, and in order to drive at this timing, the reference voltage and drive time t are set in advance to constant values.

[Problems to be Solved] The above circuit configuration is difficult to integrate, and is contrary to miniaturization and cost reduction.

Also, the reference voltage may vary depending on the length and period of the pendulum.
The adjustment work was complicated because it had to be set to an appropriate value each time.

Furthermore, when starting the pendulum from a stopped state, it is extremely difficult to stabilize the swing of the camera to a steady state.

The present invention has been made to solve the above-mentioned conventional problems,
It can be easily integrated, and the base I can be used regardless of the length or period of the pendulum.
It is an object of the present invention to provide an electromagnetic drive circuit that can automatically set the fl voltage to an optimum value and can quickly stabilize the swing of a pendulum from a stopped state to a steady state.

[Means for Solving the Problems] The present invention provides a coil for detecting and driving a permanent magnet, and a base! a variable reference voltage source that generates an fI voltage, a comparator circuit that generates an output when the induced voltage in the coil exceeds the reference voltage, and a pulse generator that generates a drive pulse in response to the generation of the output from the comparator circuit. a drive circuit that operates according to the drive pulse and causes a drive current to flow through the coil;
A counting circuit capable of raising and lowering the reference voltage of the variable reference voltage source, a control circuit controlling designation of up or down mode of the counting circuit, and a clock circuit supplying a clock signal to the counting circuit. The above object is achieved by the electromagnetic drive circuit.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, LL is a coil that detects and drives the permanent magnet of the pendulum, VR is a variable reference voltage source, and CM is a coil that compares the induced voltage generated in the coil LL with the reference voltage of the reference voltage source VR. A comparison circuit that generates an output when the induced voltage exceeds the base voltage, PG is a pulse generation circuit that generates a pulse of a predetermined width in response to the output of the comparison circuit CM, and DR is a pulse generation circuit that generates a pulse of a predetermined width in response to the output of the comparison circuit CM. Above coil LL
TM is a timer circuit that outputs a pulse when no pulse is generated from the pulse generation circuit PC for a predetermined period, W is a one-shot circuit that generates a one-shot pulse by the output of this timer circuit TM, and CT is a one-shot circuit that CNT is a counting circuit capable of raising and lowering the base L$- voltage of the variable base voltage iVR according to its output, and CNT is a counting circuit that can increase or decrease the base voltage of the variable base voltage iVR in response to the output of the pulse generation circuit PG and the output of the timer circuit TM. This is a control circuit that controls the up and down movements of the CT. CL is a clock circuit that is composed of an oscillation circuit, a frequency dividing circuit, and an output circuit, and supplies clock pulses to the counting circuit CT. When this example is applied to a watch, the clock pulses include output pulses to a motor, etc. can be used.

All of the above elements except the coil LL can be integrated, which is extremely effective in reducing the size and cost of the circuit.

Next, the operation of the above circuit will be explained according to the time chart shown in FIG.

Note that a % f shown in FIG. 2 indicates the state of points a to f in FIG. 1. The induced voltage of the coil LL at point a is equal to the reference voltage iVR.
When the voltage V n-1 is exceeded, an output is generated from the comparison circuit CM, and in response to this output, a pulse of a predetermined voltage value is generated from the pulse generation circuit PC for a predetermined period. This pulse causes current to flow through the drive circuit DR to the coil LL,
Apply driving energy to a permanent magnet (not shown). This pulse simultaneously sets the RS flip-flop of the control circuit CNT to set the counting circuit CT to the up mode and resets the timer circuit TM.

When a clock pulse is generated from the clock circuit CL in this state, the counting circuit CT counts up by one count, and the count value of the counting circuit CT changes from n - 1 to n.
Based on this count value, the reference voltage [VR voltage is V n-1
It increases from Vn to Vn.

Two pulses are subsequently generated from the pulse generating circuit PG, but these pulses basically only reset the timer circuit TM, and the reference voltage remains at vn.

Next, due to the clock pulse generated from the clock circuit CL, the count value of the counting circuit CT becomes n+1, and the reference voltage of the reference voltage IVR becomes Vn+1. That is,
The reference voltage of the reference voltage source VR can be changed only by clock pulses from the clock circuit CL.

After the reference voltage of the reference voltage source VR is set to V n+1, if no output is generated from the comparator circuit CM for a predetermined period of time, an output is generated in the timer circuit TM, and this output triggers the one-shot circuit W to generate a one-shot pulse. This one-shot pulse resets the control circuit CNT, and the output of the control circuit CNT sets the counting circuit CT to the down-count mode.

When a clock pulse is generated from the clock circuit CL in this state, the counting circuit CT counts down by one count, and the count value becomes n, and this count value causes the reference voltage of the reference voltage source VR to drop to Vn.

As described above, when the magnitude of the reference voltage and the induced voltage are compared and the induced voltage is larger, the reference voltage is increased by one step, and when the induced voltage is smaller (in the above embodiment, the induced voltage is is smaller), the reference voltage of the reference voltage source VR is automatically set to the optimum voltage by lowering the reference voltage by one step.

By the way, when starting the pendulum from a stopped state, the reference voltage of the reference voltage source gradually increases until it reaches a steady state. However, if this rising speed is too fast or too slow, the pendulum will not swing stably due to reasons such as not being able to supply driving energy to the pendulum at the optimal timing or not being able to supply enough driving energy to the pendulum. cannot be driven.

In this example, the clock pulse can be generated from the clock circuit CL at any period, and the reference voltage can be increased at any speed, so the pendulum can be driven under optimal driving conditions, and the pendulum swing can be started quickly. can be stabilized.

Usually, one period of the clock pulse is preferably about several times one period of the pendulum. For example, one period of a pendulum is 0.5
-1.5 seconds, one period of the clock pulse is preferably about 2 to 8 seconds.

In particular, in the above example, the driving pulse of the watch's motor is used as the clock pulse, and the period is usually about 1 to 2 seconds, so it is suitable for the clock pulse, and a frequency divider circuit is specially designed to generate the clock pulse. There is no need to add etc.

Note that in the above embodiment, the up mode of the counting circuit CT,
In both the down mode, the counting operation was performed using clock pulses from the clock circuit, but the clock pulses may be used only in the up mode, and the output pulses from the one-shot circuit W, for example, may be used in the down mode.

Further, in addition to an up/down counter, an addition/subtraction circuit or the like can be used as the counting circuit CT.

Next, a specific example of the pulse generation circuit PC will be explained.

In FIG. 3, G 1 and G 2 are gate circuits, Fl is a flip-flop circuit, and IN is an inverter. W,
W4 is a one-shot pulse generating circuit, and the respective pulse widths are set to tl and t2. Note that the same reference numerals as in FIG. 1 indicate the same things.

In the above configuration, when no output is generated from the comparison circuit CM, the one-shot pulse generation circuits W 1 and W 2 are set and reset, respectively, by the output of the gate circuit G3. Therefore, when the induced voltage in the coil LL exceeds the reference voltage V as shown in Fig. 4, the comparator circuit CM
From this, an output is generated as shown in Figure 4, and the setting and reset of the one-shot pulse generation circuits W and W4 are released via the gate circuit G3.Therefore, the output of the one-shot pulse generation circuit W3 is as shown in Figure 4. As shown in (2), after the time tl, the signal is inverted, which triggers the one-shot pulse generation circuit W4, and a pulse having a width of time t2 is generated from its output.

In this way, the one-shot pulse generation circuits W 1 and W 2 oscillate, and the output of the one-shot pulse generation circuit W 3 produces a fourth pulse.
The drive pulse train shown in Figure ■ is generated. By the rising edge of the first pulse of this drive pulse train, the flip-flop circuit F1
is triggered, and its output Q is held at "1" as shown in FIG. Therefore, the output of the gate circuit G3 is held at 1 degree from the generation of the output of the comparator circuit CM, as shown in FIG. 4, and a driving pulse train is generated from the gate circuit G4, as shown in FIG. This drive pulse train turns on the drive circuit DR using transistors, and a drive current flows through the coil LL.

The drive pulse train is supplied to the clock input of the flip-flop circuit F1, and its rising edge (thereby, the output state of the comparator circuit CM is determined).

Therefore, while the output from the comparator circuit CM is zero, the drive pulse train is generated and the coil LL is driven.

Then, the induced voltage becomes less than the reference voltage v, and the comparator circuit C
When the output of M stops, the output of the flip-flop circuit F is reversed to "0" by the rising edge of the first drive pulse, and the drive < 7 response train stops, and the coil L
The drive of L stops.

As described above, the drive current flows through the coil while the induced voltage exceeds the reference voltage v.

When the above-mentioned circuit is used as the pulse generating circuit PG, the output of the gate circuit G1 is used as the power of the gate circuit G in FIG. 1, the reset input of the timer circuit TM, and the set power of the flip-flop circuit F.

Incidentally, although omitted in the above explanation, the output width t2 of the one-shot pulse generation circuit W is set as follows. Since the coil LL is driven by a drive pulse train, when this pulse is interrupted, ringing r usually occurs for about 1 mS as shown in Figure N4 (■). While this ringing is occurring, the induced voltage in the coil LL becomes unstable, so if the next drive pulse is generated during this period and the output of the comparator circuit CM is determined by the flip-flop circuit F1,
There is a risk of malfunction. Therefore, the output width t2 of the one-shot pulse generation circuit W4 is set to about several milliseconds so that the next drive pulse is generated in a state where the induced voltage is stable.

Note that when driving the coil, even if there is a drive stop time of about several milliseconds, it does not affect the energization of the permanent magnet and can be ignored.

In the above embodiment, the reference voltage V that determines the drive start timing and the drive stop timing is set to the same voltage, but it is also possible to adjust the drive end timing by making them different. By switching the output of the flip-flop circuit F1 to the voltage vrl as shown in FIG. be.

Incidentally, the amplitude of the induced voltage is generally affected by fluctuations in the power supply voltage. If the amplitude of the induced voltage fluctuates, the timing at which it exceeds the reference voltage will shift, resulting in fluctuations in drive timing and drive time. Therefore, in order to reduce the influence of power supply fluctuations, the base I$ lightning voltage is set to a lower voltage that is less affected by voltage fluctuations, and the output from the comparator circuit is passed through a delay circuit (not shown). It is also possible to delay the drive by a certain period of time and start driving from this point.For example, as shown in Fig. 4 (■), by setting the base/$ voltage to a low voltage ■r2, the induced voltage becomes the voltage vr2. When the time exceeds t, an output is generated from the comparator circuit, which is delayed by a delay circuit for a time t.

The signal is supplied to the flip-flop circuit F and the gate circuit G3 with a delay of 10 minutes. This makes it possible to reduce the influence of fluctuations in power supply voltage, and to drive the coil at optimal timing and drive time.

Next, another example of the pulse generation circuit PG will be explained.

In FIG. 5, F2 is a flip-flop circuit, W5~
W8 is a one-shot pulse generation circuit, and the one-shot pulse generation circuit W6 uses a programmable one-shot circuit with variable output pulse width, and the pulse widths of the one-shot pulse generation circuits W5゜w and w are respectively t.
,ts.

It is set to t. CT t is an up-down karanta.

In the above configuration, it is assumed that the content of the counter CT1 is U, thereby setting the pulse width of the one-shot pulse generating circuit W6 to t4.

When the induced voltage exceeds the reference voltage V, an output is generated from the comparison circuit CM as shown in Figure 6 (■), the one-shot pulse generation circuit W5 is triggered, and a pulse with a width t3 is generated. With the fall of , a drive pulse having a width t4 is generated from the one-shot pulse generation circuit W6, the drive circuit DR is turned on, and a drive current flows through the coil LL.

The fall of this drive pulse causes the one-shot pulse generation circuit W7 to generate a pulse with a width t5, and the fall of the drive pulse triggers the flip-flop circuit F2 and the one-shot pulse generation circuit W,8. The output of the comparison circuit CM is supplied to the D input of the flip-flop circuit F2, and this output state is read into the flip-flop circuit F2. That is, the one-shot pulse generation circuit W7
It is determined whether the level of the induced voltage at the falling edge of the pulse from V exceeds the reference voltage V. If it exceeds the reference voltage, the output of the flip-flop circuit F2 becomes "1". , the counter CT1 enters the up mode. That is, in this case, it is determined that the drive pulse width is short and that the induced voltage is not generated efficiently around the maximum point.

On the other hand, as the pulse from the one-shot pulse generating circuit W7 falls, a pulse having a width te is generated from the one-shot pulse generating circuit W8, and this becomes the clock input of the counter CT1. As a result, the content of the counter CTl increases by one and becomes (u+1) as shown in FIG. 6p. Therefore, the pulse width of the one-shot pulse generation circuit W6 is set to be longer than the previous time.

Therefore, next time, the drive pulse width will be longer, and the pulse width of the drive pulse will be corrected.

This operation is repeated until the contents of the counter become m.
Assume that the drive pulse width becomes t4 as shown in FIG.

At this time, when the induced voltage level at the falling edge of the pulse from the one-shot pulse generation circuit W7 becomes lower than the reference voltage, the output of the flip-flop circuit F2 is inverted to "0" as shown in FIG. Goes into down mode.

Therefore, the content of the counter CTl decreases to (m-1), and the next drive pulse width becomes shorter by one step.

Therefore, the drive pulse width is stabilized by being alternately switched to t' and one step shorter than t'.

In this way, the drive pulse width can be automatically stabilized at a predetermined width at the optimal timing and stabilized at a constant swing angle.In the above example, only the drive pulse width was adjusted. , one-shot pulse generation circuit W
, W using a programmable one-shot circuit,
These pulse widths may also be adjusted as appropriate depending on the contents of the counter CT1. For example, if you want to set the swing angle of the pendulum small, the amplitude of the induced voltage in a stable state is small as shown in Figure 7a, and changes slowly, so the time t3 to t5 will be slightly smaller as shown in Figure 7a. It needs to be stabilized over a long period of time. Also, if you want to set a large swing angle of the pendulum, in a stable state, the amplitude of the induced voltage will increase and the change in amplitude will become steep, as shown in Figure 7.
The width of the drive pulse may also be short. Therefore, time t −
t5 needs to be stabilized in a relatively short time compared to that in FIG. 7a.

In the state of FIG. 7a and the state of FIG. 7S, the times ta, t
The ratio of time t4 to s is different, and by adjusting this ratio, a stable swing angle is set. For example, if you want to stabilize the state shown in Figure 7, set the pulse widths of the one-shot pulse generation circuits W5 to W7 so that each time has the ratio shown in the figure, and then The pulse width is set so that each pulse width is changed while maintaining this ratio.

Therefore, by automatically adjusting the times t3 to t5 as described below, the desired swing angle is stabilized. Depending on the contents of the counter CT1 in the initial state, the pulse width of the one-shot pulse generation circuits W5 to W7 is set to the seventh pulse width.
It is assumed that the value is set to the value shown in the figure. When the power is turned on in this state, the pendulum starts to vibrate, but since the swing angle is initially small, an induced voltage similar to that shown in FIG. 7a is generated. Therefore, at the time of the fall of the pulse from the one-shot pulse generation circuit W7, the induced voltage exceeds the reference voltage, it is determined that the drive pulse width is short, the contents of the counter CT are incremented by one, and the time t3 to t5 is The time is set one step longer. This operation is repeated and the time t3 to t5 increases step by step. In this way, the driving pulse width gradually increases, and following this, the swing angle of the pendulum gradually increases with a slight delay, and the amplitude of the induced voltage also increases accordingly.

Therefore, at a certain point, the drive pulse width becomes excessive, the counter CT1 switches to the down mode, and the time t
-t 5 is decreasing. Following this, the swing angle of the pendulum becomes smaller with a slight delay.

By repeating the above operations, the state approaches the state shown in FIG. 7, and eventually becomes stable in this state. In other words, automatic adjustment is performed so that driving is performed efficiently with the optimum drive pulse width at the maximum point of the induced voltage.

By the way, the pulse width t5 of the one-shot pulse generation circuit W7 is set so that the timing for determining the level of the induced voltage is performed at the point where it is easiest to determine the induced voltage. The settings should also take into account ringing.

In the above embodiment, the reference voltage for determining the drive start timing and the reference voltage for determining the induced voltage level after the end of the drive are the same voltage V, and the latter is set to the counter CT.
It may be changed depending on the content of t. for example,
The reference voltage is switched to a voltage corresponding to the contents of the counter CT1 only while output pulses from the one-shot pulse generation circuits W6 to W8 are being generated. This has the same meaning as adjusting the pulse width of the one-shot pulse generation circuit W7.

Note that unless fluctuations in the power supply voltage are taken into consideration, the one-shot pulse generation circuit W5 is not necessarily necessary, and the comparison circuit C
The output of M may be directly supplied to the one-shot pulse generation circuit W6.

Furthermore, in the above embodiment, a clock pulse is supplied to the counter CT1 every drive pulse, but for example, when the up/down mode of the counter CT1 is constant for three consecutive drive pulses, the clock pulse is supplied to the counter CT1 for each drive pulse. You may also upload one content. The same applies to the down mode.

In this case, a ternary counter may be provided between the one-shot pulse generating circuit W and the counter CT1, and this counter may be configured to be reset each time the output level of the flip-flop circuit F2 is inverted. This makes it possible to prevent malfunctions due to noise or the like.

[Effects] According to the present invention, since circuit elements can be integrated, it is possible to easily realize miniaturization or cost reduction of the circuit.

Furthermore, since the voltage of the reference voltage source is increased or decreased in accordance with the output state of the comparator circuit, the swing of the pendulum can be automatically stabilized.

Furthermore, when the pendulum is started from a stopped state, the reference voltage can be increased at any speed using a clock pulse from the clock circuit, so the swing of the pendulum can be quickly stabilized to a steady state.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, FIG. 2 is a voltage waveform diagram of the electric circuit shown in FIG. 1, and FIG.
Electrical circuit diagram showing a part of the electrical circuit diagram in detail, No. 4
The figure is a voltage waveform diagram of the electric circuit shown in Figure 3, Figure 5 is an electric circuit diagram showing another example of Figure 3, Figures 6 and 7 are the voltage waveform diagram of the electric circuit shown in Figure 5. The voltage waveform diagram in FIG. 8 is an electric circuit diagram of a conventional example. Applicant Seikosha Co., Ltd.

Claims (1)

[Scope of Claims] A coil for detecting and driving a permanent magnet, a variable reference voltage source for producing a reference voltage, a comparator circuit for producing an output when the induced voltage in the coil exceeds the reference voltage, and this comparison. a pulse generation circuit that generates a drive pulse in response to output generation from the circuit; a drive circuit that operates in response to the drive pulse and causes a drive current to flow through the coil; and an up/down circuit that specifies the reference voltage of the variable reference voltage source. 1. An electromagnetic drive circuit comprising: a counting circuit capable of controlling the counting circuit; a control circuit for controlling designation of an up or down mode of the counting circuit; and a clock circuit for supplying a clock signal to the counting circuit.