JPH05291904A - Electromagnetic drive circuit - Google Patents

Abstract

PURPOSE:To drive a coil in a very efficient timing at all times and to prevent malfunction without being affected by an amplitude of an induced voltage. CONSTITUTION:When an induced voltage in a coil L2 exceeds a reference voltage V2, an output is produced from a comparator circuit CM and a drive pulse is generated from a one-shot pulse generating circuit W2 with a prescribed time delay T1 and the drive circuit T is active. When the output from the comparator circuit CM is interrupted for the time T1, the production of the drive pulse is stopped by an output of a circuit G3.

Description

Detailed Description of the Invention

[0001]

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.

[0002]

2. Description of the Related Art For example, a drive circuit for detecting and driving a pendulum of a timepiece with one coil is shown in FIG.

[0003] The circuit includes a coil L ₂ a 2-pole permanent magnet such as those and FIG. 6 of the type driven to face the coil L ₂ and one pole of the pendulum of the permanent magnets M as Figure 5
It can be used as both of the type that is driven facing each other. Here, the operation for driving the type shown in FIG. 6 will be described. Magnet M is the 7th
As shown in FIG. A, when the coil L ₂ moves in the direction of the arrow and faces the coil L ₂ , the maximum induced voltage v ₁ shown in FIG. Conversely, when the magnet M moves from the opposite direction and faces the coil L ₂ as shown in FIG. 7B, the maximum induced voltage v of FIG. 8A is excited in the direction in which the magnet M is stopped in this case as well. ₂ occurs.

At this maximum point, that is, it is most preferable in terms of efficiency to apply a drive current to the coil to energize the magnet at the timing shown in FIG. 7A or B.

Therefore, the threshold voltage of the transistor T ₂ shown in FIG. 4 is set to the voltage v _r shown in FIG. As a result, when the induced voltage exceeds the voltage v _r , the transistor T ₂ is turned off and the transistor T ₁ is turned on to drive the coil L ₂ at the timing of the induced voltage v ₁ as shown in FIG. 8A. A current flows and the magnet M is energized.

The type shown in FIG. 5 is also set so that the drive current flows through the coil at the maximum point of the induced voltage, as in the above case.

[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 deviated due to the amplitude fluctuation of the induced voltage, and the drive efficiency may be reduced.

That is, for example, when the amplitude of the induced voltage becomes small as shown in FIG. 8B, the timing of reaching the voltage v _r is delayed, and the drive current flows through the coil later than the optimum timing.

On the contrary, when the amplitude of the induced voltage becomes large, the drive current flows through the coil earlier than the optimum timing, and the drive efficiency is lowered in any case. Therefore, in order to keep the driving efficiency at an optimum level, it is necessary to eliminate variations in various factors that affect the amplitude of the induced voltage, and the precision of manufacturing and assembling is strictly required.

The present invention is not affected by the amplitude of the induced voltage,
The coil can always be driven at an efficient timing, and a malfunction can be prevented.

[0011]

According to the present invention, the reference voltage for coil detection is set to a low level in which the amplitude fluctuation of the induced voltage is small, and when the induced voltage of the coil exceeds the reference voltage, a fixed time is required. Therefore, the drive pulse is generated at an optimum timing by delaying only the above, and the drive pulse is generated only when the induced voltage continuously exceeds the reference voltage for a set time or longer in order to ensure the operation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, L ₁ is a detection and drive coil for a permanent magnet (not shown), V _r is a reference voltage generation source, and a reference voltage v _r at a lower level than in the prior art is used as shown in FIG. It is set to occur. CM is a comparison circuit for comparing the induced voltage of the coil L ₁ and the reference voltage v _r . G ₁ ,
G ₂ is a gate circuit, and G ₃ is a gate circuit which constitutes an inhibition circuit. W _{1 to} W ₃ are one-shot pulse generation circuits which generate pulses of widths T _{1 to} T ₃ , respectively. The one-shot pulse generation circuit W ₁ , W ₂ constitutes an output generation circuit, and the one-shot pulse generation circuit W
₂ , W ₃ and the gate circuits G ₁ , G ₂ form a prohibition circuit. T is a transistor forming a drive circuit.

In the above configuration, the induced voltage of the coil L ₁ is compared with the reference voltage v _r by the comparison circuit CM, and when the induced voltage exceeds the reference voltage v _r as shown in FIG. 2A, the comparison circuit CM outputs it. Occurs, the one-shot pulse generation circuit W ₁ is triggered via the gate circuit G _1, and a pulse of width T ₁ is generated from the output. This time T ₁ is set to the time from when the induced voltage exceeds the reference voltage v _r until the drive pulse is generated at the optimum timing at the maximum point of the induced voltage. That is, the one-shot pulse generation circuit W ₂ is triggered by the falling edge of the pulse,
A drive pulse of width T ₂ is generated from the output. This drive pulse turns on the transistor T, and the coil L
_The drive current flows to ₁ and the magnet is energized at the optimum timing.

The one-shot pulse generation circuit W ₃ is triggered by the trailing edge of the drive pulse, and a pulse of width T ₃ is generated from the output thereof. This pulse and the preceding drive pulse are supplied to the gate circuit G ₂ , and the gate circuit G ₁ is closed during the generation of each pulse. That is, during the times T ₂ and T _{3 in} FIG. ₂ , even if an output is generated from the comparison circuit CM, the one-shot pulse generation circuit W ₁ is not triggered, and a malfunction is prevented. This is because the reference voltage v _r is set to a low level, so that the induced voltage may exceed the reference voltage even when it is not maximum, and in this case, a drive pulse is prevented from being generated. is there.

The output of the one-shot pulse generating circuit W ₁ may also be supplied to the gate circuit G _{2 so} that the gate circuit G ₁ is closed during the time T ₁ .

By the way has been omitted in the above description, the output of the one-shot pulse generating circuit W ₁ is gate - Yes supplied to preparative circuit G _3, while the pulse is generated gate - is collected by circuit G ₃ is open. Therefore, during this period, the comparison circuit C
When the output of M is stopped, the one-shot pulse generation circuit W
₁ to _W-3 is reset, the generation of the drive pulse is suppressed. This is to prevent malfunction due to noise or an induced voltage other than the maximum point, and is considered as a maximum induced voltage only when the reference voltage v _r is continuously exceeded for a time T ₁ or longer, and only in this case. This is to generate a drive pulse.

In the above configuration, even if the amplitude of the induced voltage becomes small as shown in FIG. 2B, the reference voltage v _r is set to a low level, so that the amplitude fluctuation in this vicinity is extremely small and the comparison is made. The generation timing of the output from the circuit CM is almost the same as that in the case of FIG. 2A. Therefore, the generation timing of the drive pulse hardly shifts, and the drive pulse can be reliably generated at the maximum point of the induced voltage. The same applies when the amplitude of the induced voltage becomes large.

In the above example, the case of using the two-pole magnet as shown in FIG. 6 has been described, but it can be similarly applied to the case of using the one-pole magnet as shown in FIG. is there. The waveform of the induced voltage 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 as in the above case.

[0019]

According to the present invention, when the induced voltage of the coil exceeds the reference voltage, the drive current is passed through the coil with a delay of a predetermined time. Therefore, the reference voltage should be set to a low level. Therefore, the generation timing of the drive pulse is hardly influenced by the fluctuation of the amplitude of the induced voltage, and the drive current can be always supplied to the coil at the most efficient timing. Therefore, the manufacturing and assembling process is not required to have a higher precision than the conventional one, and the manufacturing and assembling process can be simplified.

Further, by generating the drive pulse only when the induced voltage continuously exceeds the reference voltage for a predetermined time or longer, it is possible to prevent malfunction due to induced voltage, noise, etc. other than the maximum time.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is a voltage waveform diagram for explaining the operation of FIG.

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 of a pendulum and a coil.

FIG. 6 is an explanatory diagram showing another example of the relationship between a pendulum and a permanent magnet.

FIG. 7 is an explanatory diagram showing an exciting magnetic pole property of the coil in the example of FIG. 6;

FIG. 8 is a voltage waveform diagram for explaining the operation of FIG.

[Explanation of symbols]

L ₁ ... coil V _r ... reference voltage generating source CM ... comparison circuit W ₁ ~W ₃ ... one-shot pulse generating circuit T ... driving circuit G ₁ ~G ₃ ... gate - DOO circuit

Claims (1)

[Claims] 1. A coil for detecting and driving a permanent magnet, a comparator circuit for producing an output when an induced voltage of the coil exceeds a reference voltage, and a coil of a prescribed width delayed by a prescribed time from the output of the comparator circuit. An output generation circuit that generates a drive pulse, a suppression circuit that suppresses the generation of a drive pulse from the output generation circuit when the output from the comparison circuit is interrupted during the predetermined time, and an output generation circuit from the output generation circuit. An electromagnetic drive circuit comprising a drive circuit which operates by a drive pulse and supplies a drive current to the coil.