JP2739098B2 - Electromagnetic drive circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic drive circuit used for driving a pendulum or the like. 2. Description of the Related Art FIG . 4 shows a drive circuit for detecting and driving a pendulum of a timepiece with one coil, for example. [0003] The circuit is the one pole of the pendulum of the permanent magnet M of the two poles of the permanent magnet is opposed to the coil L2 such as those and 6 of the type driven to face the coil L2 as shown in FIG. 5 It can be used for both of the driving type. Here, the operation when the type shown in FIG. 6 is driven will be described. When the magnet M moves in the direction of the arrow as shown in FIG. 7A and opposes the coil L2, a maximum induced voltage v1 of FIG. 8A is generated in the coil L2, which excites the magnet M in a direction to stop. Conversely, figure
7 magnets M as B is moved from the opposite direction the coil L
2A , the maximum induced voltage v2 of FIG. 8A is generated, which also excites the magnet M in the direction to stop. At this maximum point, that is, at the timing shown in FIG. 7A or B, it is most preferable from the viewpoint of efficiency to drive the magnet by supplying a drive current to the coil. [0005] Therefore the threshold voltage of the transistor T2 of FIG. 4 is intended to set the voltage vr of FIG. As a result, when the induced voltage exceeds the voltage vr, the transistor T2 is turned off, and the transistor T1 is turned on . As shown in FIG. 8A , a driving current flows through the coil L2 at the timing of the induced voltage v1, and the magnet M Is energized. [0008] The type shown in FIG. 5 is also set so that a drive current flows through the coil at the maximum point of the induced voltage in the same manner as described above. [0007] Generally, the amplitude of the induced voltage varies depending on the number of turns of the coil, the strength of the magnetic force of the magnet, the distance between the coil and the magnet, and the like. In the above-described conventional configuration, the drive timing of the coil may be shifted due to the variation in the amplitude of the induced voltage, and the drive efficiency may be reduced. That is, when the amplitude of the induced voltage is reduced as shown in FIG. 8B , for example, the timing of reaching the voltage vr is delayed, and the drive current flows through the coil later than the optimum timing. Conversely, when the amplitude of the induced voltage increases, the drive current flows through the coil earlier than the optimum timing, and in any case, the drive efficiency is reduced. Therefore, in order to maintain the driving efficiency at an optimum, it is necessary to eliminate variations in various factors affecting the amplitude of the induced voltage, and precision in manufacturing and assembling is strictly required. The present invention is not affected by the amplitude of the induced voltage,
The coil can be driven at an efficient timing, and a malfunction can be prevented. SUMMARY OF THE INVENTION The present invention is directed to a coil
A reference voltage for detecting the induced voltage, the amplitude variation of the induced voltage may be set to a small low level, delayed by Jo Tokoro time when the induced voltage of the coil exceeds the reference voltage efficiency
The drive pulse is generated at a good timing, and the drive pulse is generated only when the induced voltage exceeds the reference voltage continuously for a predetermined time or more for reliable operation. FIG . 1 shows a permanent magnet L1 (not shown).
Detection and drive coil, Vr is the reference voltage source .
As shown in FIG. 2 , the reference voltage vr is set to be lower than the conventional one. CM is a comparison circuit for comparing the induced voltage of the coil L1 with the reference voltage vr. G1 and G2 are gate circuits, and G3 is a gate circuit constituting a control circuit. W1 to W3 are one-shot pulse generation circuits for generating pulses having widths T1 to T3, respectively. One-shot pulse generators W1 and W2 constitute an output generator, and one-shot pulse generators W2 and W3 and gate circuits G1 and G2 constitute an inhibit circuit. T is a transistor constituting a drive circuit. In the above configuration, the induced voltage of the coil L1 is compared with the reference voltage vr by the comparison circuit CM .
When the induced voltage exceeds the reference voltage vr as in 2A, an output is generated from the comparison circuit CM, the one-shot pulse generation circuit W1 is triggered via the gate circuit G1, and a pulse having a width T1 is output from the output. Occur. The time T1 is set to a time from when the induced voltage exceeds the reference voltage vr to when a drive pulse is generated at an optimum timing at the maximum point of the induced voltage. That is, the falling of the pulse triggers the one-shot pulse generation circuit W2, and a drive pulse having a width T2 is generated from its output. The transistor T is turned on by this driving pulse, and the coil L1
, A driving current flows, and the magnet is energized at an optimal timing. The falling of the drive pulse triggers the one-shot pulse generation circuit W3, and a pulse having a width T3 is generated from its output. This pulse and the preceding drive pulse are supplied to the gate circuit G2, and the gate circuit G1 is closed during the generation of each pulse. That is, during the times T2 and T3 in FIG. 2 , even if an output is generated from the comparison circuit CM, the one-shot pulse generation circuit W1 is not triggered, and malfunction is prevented. This is because the reference voltage vr is set to a low level, so that the induced voltage may exceed this reference voltage even at times other than the local maximum, and in this case, a drive pulse is prevented from being generated. . The output of the one-shot pulse generating circuit W1 may also be supplied to the gate circuit G2 so that the gate circuit G1 is closed during the time T1. Incidentally, although omitted in the above description, the output of the one-shot pulse generation circuit W1 is supplied to the gate circuit G3, and the gate circuit G3 is open while the pulse is being generated. . Therefore, during this time, the comparison circuit C
When the output of M stops, the one-shot pulse generation circuit W
1 ～W3 is reset, the drive pulse is generated
There is no. This is to prevent malfunction due to noise or induced voltage other than the maximum point. When the voltage exceeds the reference voltage vr continuously for the time T1 or more, it is regarded as the maximum induced voltage. Is to be generated. [0017] In the above configuration, the amplitude of the induced voltage in FIG.
Even if as 2 B small, since the reference voltage vr has been set to a low level, amplitude fluctuations is very small in this vicinity, the generation timing of the output from the comparison circuit CM Figure 2
It is almost the same as A. Therefore, the generation timing of the drive pulse is hardly shifted, and the drive pulse can be reliably generated at the maximum point of the induced voltage. The same applies to the case where the amplitude of the induced voltage increases. In the above example, the case where a two-pole magnet as shown in FIG. 6 is used has been described . However, the same can be applied to a case where a one-pole magnet as shown in FIG. 5 is used.
The induced voltage waveform in this case is as shown in FIG. 3 , and the drive current flows through the coil at the maximum point of the induced voltage in the same manner as described above. According to the present invention, when the induced voltage of the coil exceeds the reference voltage, the drive current is supplied to the coil with a delay of a predetermined time, so that the reference voltage is set to a low level. Therefore, the drive pulse generation timing is almost unaffected by the amplitude fluctuation of the induced voltage.
It not, can flow a driving current to the coil in good time of efficiency. Therefore, high precision is not required for the manufacturing and assembling, and the manufacturing and assembling process can be simplified. Further, by generating a drive pulse only when the induced voltage continuously exceeds the reference voltage for a predetermined time or more, malfunction due to induced voltage, noise, and the like other than at the time of the maximum can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electric circuit diagram showing one embodiment of the present invention. 2 is a voltage waveform diagram for explaining the operation of Figure 1. FIG. 3 is a voltage waveform diagram when the circuit of FIG . 1 is used in another example. FIG. 4 is an electric circuit diagram showing an example of a conventional electromagnetic drive circuit. FIG. 5 is an explanatory diagram showing an example of a relationship between a permanent magnet and a coil of a pendulum. FIG. 6 is an explanatory diagram showing another example of the relationship between the pendulum and the permanent magnet. FIG. 7 is an explanatory diagram showing excitation polarities of a coil in the example of FIG . 6 ; 8 is a voltage waveform diagram for explaining the operation of Figure 4. [Explanation of Signs] L1 ... Coil Vr ... Reference voltage source CM ... Comparing circuits W1 to W3 ... One shot pulse generating circuit T ... Drive circuit G3 ... Control circuit

Claims (1)

(57) [Claims] Induced voltage is generated as the permanent magnet reciprocates
A coil for energizing the movement of the permanent magnet, a comparison circuit for generating an output when the induced voltage of the coil exceeds a reference voltage, and a drive pulse of a predetermined width delayed by a predetermined time from the generation of the output from the comparison circuit. an output generating circuit for generating a, to generate the drive pulse from the output generating circuit when the output from the comparator circuit is interrupted during the predetermined time period
And no control circuit, the permanent magnetic operated by a drive pulse from the output generating circuit to flow a driving current to the coil
An electromagnetic drive circuit consisting of a drive circuit for energizing the rock .