US3818376A - Method and apparatus for synchronizing the balance system of clocks or wrist watches - Google Patents

Abstract

A watch pulse synchronizing circuit includes a transistor driver stage in a given circuit arrangement with a drive coil for a watch balance system and a transistor switching stage controlled by a sync pulse. The vibration frequency of the balance system is slightly higher or lower than one half of the sync frequency. The sync signal through action of the switching stage turns the driver stage on and off once for each half vibration of the balance system. Changes between the vibration and sync frequency changes the width of a primary pulse and generates a secondary pulse to charge a capacitor so that the sum of the energy of the two pulses remain constant for the output of the driver coil.

Description

United States Patent [191 Keller et al.

[111 I 3,818,376 June 18, 1974 METHOD AND APPARATUS FOR SYNCHRONIZING THE BALANCE SYSTEM OF CLOCKS OR WRIST WATCHES Inventors: Hans Keller, Freiburg; Wolfgang Schultz, Waldkirch, both of Germany Assignee: lTT Industries, New York, NY.

Filed: Feb. 16, 1973 Appl. N0.: 333,428

[30] Foreign Application Priority Data Mar. 4, 1972 Germany 2210542 US. Cl. 331/116 M, 58/23 A, 318/128, 331/172 Int. Cl G04c 3/00, H03b3/04, H03b 5/30 Field of Search 331/116 M, 172; 58/23 A, 58/23 AC, 28 A; 318/128 References Cited UNITED STATES PATENTS 5/1970 Shelley et a1 331/1 16 M X 3,618,311 11/1971 Wiesner et a1. 331/116M X Primary Eraminer-Herman Karl Saalbach Assistant Eraminer-Siegfried H. Grimm Attorney, Agent, or Firm-John T. OHalloran; Menotti .l. Lombardi, Jr.; Alfred C. Hill [57] ABSTRACT driver stage on and off once for each half vibration of the balance system. Changes between the vibration and sync frequency changes the width of a primary pulse and generates a secondary pulse to charge a capacitor so that the sum of the energy of the two pulses remain constant for the output of the driver coil.

4 Claims, 5 Drawing Figures PAIENIEDJUNI 1w 3.818.376

' sum 10? 3 MAGNET TYPE R BALANCE SYSTEM MAGNET 7 2 L TYPE Q A BALANCE L SYSTEM 2 E A CRYSTAL K R2 OSCILLATOR AND fi- FREQUENCY L CRY5TAL DIVIDER OSCILLATOR I AND Fly-l y 5 FREQUENCY DIVIDER A/\ a) I V Fig.2

PATENTEDJUN 1 81974 SHEET 2 OF 3 zfo f PATENTEDJUHWW 3.818.378 SHEET 30F 3 Fig.4

BACKGROUND OF THE INVENTION The step-by-step devices primarily considered for use as electromechanical transducers for utility-type crystal-controlled clocks and particularly for crystalcontrolled wrist watches are relatively sensitive to shock. Electromagnetically driven balance systems show a much better behavior in this respect.

The vibration frequency of a balance system depends on, among other things, the kind of energy supply. This fact, which is disadvantageous in itself, can be used to synchronize an electromagnetically driven balance system.

It is known, for example, from German published Patent Application 2,01 1,233 that a simple one or twocoil balance system driven automatically by a suitable circuit can be synchronized if, in addition to the main drive pulse, one or more auxiliary drive pulses are applied which are shifted in time relative to the reference position of the balance system and are triggered by the sync signal occurring several times during a vibration of the balance system, i.e., the frequency of the sync pulses is several times higher than that of the balance system vibration. In that method, however, more power than necessary is needlessly applied to the balance sys tem through the auxiliary drive pulse, so that the amplitude of vibration of the balance system increases and the battery is additionally loaded, while undesirable transient conditions occur during the control.

On the other hand, it is known from Swiss published Patent Application 12,571/67 that the vibration frequency of an electromagnetic balance system can be better synchronized if the drive coil is supplied with two successive drive current pulses having a constant total energy content, one of which is applied before the reference position of the balance system, and the other thereafter, the vibration frequency of the balance system being changed as a function of the sync signal by variation of the relative amplitude values of the two pulses.

To enable a better terminological distinction, the sole drive pulse occuring automatically with an unsynchronized drive circuit will hereinafter be referred to'as primary pulse, while the second drive pulse will be termed secondary pulse.

For the realization of the method of said Swiss Patent Application, a complicated and expensive circuit is disclosed which comprises a bridge push-pull stage, designed to drive the electromagnetic balance system, and two moving coils, which cannot be connected direct to one pole of the battery as is particularly desirable for a realization using, monolithic integrated circuit techniques. In addition, the bridge push-pull circuit is not capable of maintaining the vibrations of the balance system without the utilization of the circuit generating the sync signal. The complete circuit of the known kind operates on the principle of phase comparison between the vibration frequency of the balance system and the frequency of the sync signal. It, therefore, has several multivibrator stages and a sawtooth generator to achieve the phase comparison, which adds to the above-mentioned complexity. In addition, the

known circuit is tailored for a special coil and magnet,

system with two concentric pancake coils and a pair of magnetic poles in the direction of vibration where in the coil legs located before and behind the reference position one positive and one negative pulse is generated with each semi-vibration of the balance system, from which fact the above-mentioned use of a bridge push-pull circuit follows of necessity.

SUMMARY OF THE INVENTION The present invention therefore relates to a method of synchronizing, by means of the divided frequency of a crystal oscillator, the balance system of utility clocks, and particularly of wrist watches, which, in the direction of vibration, preferably has three pairs of magnetic poles of alternating polarity, wherein, without synchronization, the vibrations of the balance system are maintained by an automatic drive circuit through one drive pulse (primary pulse) per semi-oscillation, while, with synchronization, two successive drive current pulses (primary pulse secondary pulse) having a total energy content divided between them are applied per semi-oscillation to the drive coil of the electromagnetic balance system.

Starting from the prior art, the present invention has for its object to provide a method whereby the above described disadvantages of the arrangement disclosed in the above-mentioned German Patent Application can be avoided. Use will be made of the principle of dividing the drive current pulse at a constant total energy content of the divided drive pulses as disclosed in the above-mentioned Swiss Patent Application, with a view to considerably simplifying circuit arrangements suitable for carrying out the method.

A feature of the present invention is the provision of a method of synchronizing a balance system of clocks and wrist watches having an automatic drive circuit and a given vibration frequency comprising the steps of: generating a sync signal having a given frequency, one half of the given frequency being slightly different than the given vibration frequency of the balance system; controlling by the sync signal the conduction of the drive circuit once per semi-vibration of the balance system in such a manner that the more the given vibration frequency departs from one half of the given frequency the more the energy content of a primary pulse produced by the drive circuit is' reduced; and producing automatically in the drive circuit a secondary pulse having the same polarity as the primary pulse as the energy content of the primary pulse is reduced, the energy content of the secondary pulse being dependent on the energy content of the primary pulse, both the primary pulse and the secondary pulse providing a constant total energy content for the drive circuit.

Another feature of the present invention is the provi sion of a circuit arrangement to carry out the above method comprising: a circuit to produce a sync signal; a driving transistor of given conductivity type; a control transistor of a conductivity type complementary the given conductivity type; a balance system; a supply voltage source having a positive pole and a negative pole; a drive coil for the balance system having one end thereof coupled to one of the poles of the source; a first resistor coupled between the other end of the drive coil and the collector of the driving transistor; the emitter of the driving transistor being coupled to the other of the poles of the-source; a capacitor having one plate thereof coupled to the one of the poles of the source;

a second resistor coupled between the other plate of the capacitor and the junction of the drive coil and the first resistor; the emitter of the control transistor being coupled to the other plate of the capacitor; a third resistor and a fourth resistor coupled in series between the other of the poles of the source and the junction of the drive coil and the first and second resistors; the base of the control transistor being coupled to the junction of the third and fourth resistors; the collector of the control transistor being coupled to the base of the driving transistor; an auxiliary transistor of a conductivity type complementary to the given conductivity type, the collector of the auxiliary transistor being coupled to the other of the poles of the source, the emitter of the auxiliary transistor being coupled to the other plate of the capacitor and the base of the auxiliary transistor being coupled to the junction of the junction of the driving coil and the first and second resistors; and an additional transistor having its base coupled to the circuit to produce the sync signal and its collector-emitter path inserted at a given point in the circuit arrangement to control the conduction of the driving transistor.

A further feature of the present invention is the provision of a circuit arrangement to carry out the above method comprising: a. circuit to produce a sync signal; a supply voltage source having a positive pole and a negative pole; a balance system; a transistor having its collector-emitter path coupled to one of the poles of the source; a operating coil for the balance system disposed in the collector-emitter circuit of the transistor; a control coil for the balance system; a self-starting network including a resistor coupled between the one of the poles of the source and the base of the transistor, and a capacitor coupled in series with the control coil in the base-emitter circuit of the transistor; and an additional transistor having its base coupled to the circuit to produce the sync signal and its collector-emitter path inserted at a given point in the circuit arrangement to control the conduction of the transistor. v

The invention is based on the discovery that most conventional oneand two-coil circuits for driving electromechanical balance system can be synchronized without transient conditions and within a wide range if one of the current paths of the circuit is turned on and off or off and on by the sync signal instead of carrying out a complicated phase comparison or only applying or triggering a falsely positioned additional pulse as is the case in the prior art circuits. It is particularly advantageous if the sync-signal duration for which the current path of the automatic drive circuit is on or off is approximately equal to the duration of the voltage induced in the control coil during a semi-vibration.

BRIEF DESCRIPTION OF THE DRAWING cuit for carrying out the method in accordance with the principles of the present invention;

FIG. 2 illustrates, for the two possibilities and their signs, the voltage induced in the drive coil of FIG. 1

during one vibration of the balance system;

FIG. 3 illustrates the sync signal and the voltage waveform across the drive coil at three different balance frequencies for positive induced voltage;

FIG. 4 illustrates the sync signal and the voltage waveform across the drive coil at three different balance frequencies for negative" induced voltage; and

FIG. 5 is a schematic diagram of a conventional, selfstarting two-coil drive circuit for carrying out the method in accordance with the principles of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the one-coil drive circuit disclosed in the copending application of H. Keller and W. Sauer, Ser. No. 227,369, filed Feb. 18, 1972 now US. Pat. No. 3,742,385 which, by addition of a further transistor whose base is fed with the sync signal, was expanded so as to be suitable for carrying out the method in accordance with the principles of the present invention. However, a further transistor may also be added to most of the other known one-coil drive circuits containing a capacitor so that synchronization by a crystal oscillator with following frequency divider is made possible.

The drive circuit shown in FIG. 1 contains only the coil L, which acts as an operating and control coil. Superimposed on the voltage which is induced in coil L by the magnet system of balance system 1 and whose waveform, generated by a three-magnet system, is shown in FIG. 2 for a complete vibration of the balance system is the drive pulse generated by the circuit, as is shown in FIG. 31). One end of the coil L is connected to one pole of the supply voltage source U, while its other end is connected via resistor R3 to the collector of the driving transistor T1, whose emitter is in turn connected to the other pole of supply voltage source U. The base of driving transistor T1 of the npn conductivity type is connected to the collector of the control transistor T2, which is complementary to the driving transistor (i.e. of the pnp conductivity type) and whose emitter is connected through capacitor C to one pole of supply voltage source U. The emitter of control transistor T2 is connected via resistor R4 to the junction point of coil L and resistor R3. This junction point is connected via the voltage divider consisting of resistors R1 and R2 to the other pole of the supply voltage source U, while the junction point of the two resistors R1 and R2 has the base of the control transistor T2 connected thereto. The complementary auxiliary transistor T3 (i.e. of the pnp conductivity type) has its base connected to the junction point of coil L and resistor R3, while its collector is connected to the other pole of supply voltage source U. The emitter of the auxiliary transistor T3 is connected to the emitter of the control transistor T2. This one-coil drive circuit is capable of maintaining the vibrations of the balance system automatically.

The current path to be turned on and off by the sync signal may be provided at any point of the circuit, as required. Particularly well suited for this purpose is each of the three lines connected to the electrodes of each of the two transistors T1 and T2. It is, however, also possible to use either of the two lines connected to supply voltage source U from the circuit as the current path to be turned on and off by the sync signal.

In the embodiment of FIG. 1, the base current path of driving transistor T1 is turned on and off at the common junction point of the base of driving transistor T1 and the collector of control'transistor T2 by an additional transistor T4 of the npn conductivity type, which acts as a switch controlled by the sync signal, connected between said common junction point and the other pole of the supply voltage source U. The sync signal is produced by a crystal controlled oscillator and frequency divider 2 which may take the form disclosed in the copending application of H. Keller and W. Kreitz, Ser. No. 290,919, filed Sept. 22, 1972. The emitter of additional transistor T4 is connected to the negative pole of the supply voltage source, and its collector is connected to said -common junction point, while its base, serving as the input E, is supplied with sync signal. Hence, the inventive turning-on and -off of a current path also comprises rendering a current path of the circuit inoperative by means of a short circuit to be opened or closed and connected in parallel to the current path, as is shown in FIG. I for the base-emitter path of driving transistor T1.

As already mentioned, FIG. 2 shows the voltage induced in coil L by a three-magnet system during one vibration of the balance system. The broken vertical line gives the reference position of the balance system. The balance system passes through this reference position twice per vibration. This induced voltage comprises a positive and a negative main peak and a positive and a negative secondary or satellite peak.

FIG. 2a shows the induced voltage referred to above as positive. An induced voltage is defined as positive if the first secondary peak relative to time and the second main peak relative to time are positive. An in duced voltage is defined as negative if the first secondary peak relative to time and the second main peak relative to time are negative. This induced voltage is shown in FIG. 2b.

The use of a three-magnet system requires that in both the counterclockwise semi-vibration and the clockwise semi-vibration of the balance system the same pulse shape of the induced voltage is generated, as is shown in the two respective identical wave patterns of FIG. 2a and FIG. 2b.

In the method according to the present invention, the frequency of the sync signal f, is chosen to be about twice as high as the vibration frequency f, of the balance system, as shown in FIGS. 3 and 4. In FIGS. 3a and 4a, the output pulse of crystal oscillator and frequency divider 2 is illustrated as the sync signal. The frequency divider usually consistsof series-connected, bistable flip-flop stages and divides the oscillator frequency by a number corresponding to a power of two, with the exponent corresponding to the number of stages. Such bistable flip-flop stages deliver at their outputs a square-wave signal with a unity mark-to-space ratio, as shown in FIGS. 3a and 40.

It is not absolutely necessary, however, that the sync signal have a unity mark-to-space ratio. Other mark-tospace ratios may be chosen provided that is is insured that the duration of the sync signals pulse portion turning the current path on or off is approximately equal to the duration of the voltage induced in the coil during one semi-vibration.

FIGS. 3!) to 3d show, for positive induced voltages and for different cases of the numerical relationship between the frequency f, of the sync signal and the vibration frequency f, of the balance system, waveforms developed when the method in accordance with the present invention is carried out. In the present case it is assumed that the balance system, without any sync signal acting upon the circuit, has a natural frequency f, which results in a positive-going rate of the clock, i.e., which causes the clock to be fast. Thus, without sync signal, the vibration frequency of the balance system has been chosen to be slightly higher than one-half the frequency f, of the sync signal. The voltage pulse then appearing across the coil L is shown in FIG. 3c. In this case, the voltage drop caused across the dc. (direct current) resistance of the coil by the primary and secondary pulses is superimposed on the induced voltage. The interrelationship of positive induced voltage and gaining balance system must be employed if, as in the circuit of FIG. 1, the driving transistor is of the npn conductivity type and if, consequently, its emitter is connected to the negative pole of the supply voltage source. With a driving transistor of the pnp conductivity type, which, of course, is also possible and whose emitter would have to be connected to the positive pole of the supply voltage source, and with positive induced voltage, the balance system would then be slow.

Due to the higher repetition frequency of the induced voltage pulses relative to the sync signal, the waveform of the induced voltage as shown in FIG. 30 is shifted to the left relative to the synchronous condition of FIG. 3b. Since, in the circuit of FIG. 1, the sync signal, if positive, turns the base current path of the driving transistor off, the primary pulse I, which, without synchronization, would be possible at an earlier instant relative to the induced voltage, cannot occur until after the current path has been turned on again, i.e. after the induced voltage has become more negative than that of FIG. 3b.

Since, however, after the triggering of the primary pulse I, the circuit acts independently of the sync signal, the primary pulse I is ended after the induced voltage has exceeded a threshold value predetermined by the design of the drive circuit, i.e., the primary pulse I of FIG. 30 has a smaller width and, consequently, a lower energy content than that of FIG. 3b.

As a result of the smaller width of the primary pulse I, however, the capacitor C could not be charged through auxiliary transistor T3 to the extent shown in FIG. 3b, so that a secondary pulse II is generated whose width depends on the charging condition of capacitor C and which is of the same polarity as the primary pulse I. In the case of FIG. 3b, however, the capacitor C has been charged through auxiliary transistor T3 by the primary pulse I to such an extent, and thus the threshold of response of the control transistor T2 has been shifted to such an extent, that a second drive pulse can no longer be generated.

FIG. 3d shows the case where the balance vibration j", is even higher than in the case of FIG. 3c. In the case of FIG. 3d, the balance system vibrates so fast that the sync signal does not enable the circuit to deliver the primary pulse I until the induced voltage has exceeded its negative peak value. Therefore, the primary pulse I is very narrow. Since, in the case of FIG. 3d, the capacitor C has been charged by the narrow primary pulse I even less than in the case of FIG. 3c, the secondary pulse II is correspondingly wider.

FIGS. 4b to 4d show the corresponding waveforms for a negative induced voltage. In this case, the balance system has a natural frequency which results in a negative-going rate of the clock, i.e. which causes the clock to be slow. Thus, the vibration frequency f of the balance system is chosen to be slightly lower than one-half the frequency f, of the sync signal. Due to the lower repetition frequency of the induced voltage pulses, the

' waveform of the induced voltage as shown in FIG. 4c

is shifted to the right relative to the synchronous condition of FIG. 4b. Therefore, the primary pulse I is ended by the sync signal earlier than in the free-running condition of the drive circuit, i.e., the primary pulse I has a smaller width and, consequently, a lower energy content than that of FIG. 4b.

Here, too, similarly to the cases described with reference to FIG. 3, the reduction of the energy of the primary pulse I results in the occurrence of a secondary pulse II, whose width depends on the width of the primary pulse I in a mirror-inverted manner relative to time compared with the cases of FIG. 3, i.e., the secondary pulse II associated with a pulse of the induced voltage is linked with the primary pulse I associated with the previous pulse of the induced voltage to cause a division of the energy content of the total drive pulse. The interrelationship of negative induced voltage and losing balance system must be employed if, as in the circuit of FIG. 1, the driving transistor is of the npn conductivity type and if, consequently, its emitter is connected to the negative pole of the supply voltage source. With a driving transistor of the pnp conductivity type, which, of course, is also possible, and whose emitter would have to be connected to the positive pole of the supply voltage source, and with negative induced voltage, the balance system would be fast.

FIG. 5 shows a conventional two-coil drive circuit which is capable of starting by itself via an RC (resistorcapacitor) network and can also be synchronized by the method in accordance with the present invention. The circuit comprises the transistor T, which amplifies the pulses generated by the magnet system of balance system 1 in the control coil L, and causes these pulses to become effective in the operating coil L Thus, the operating coil L also coupled to balance system 1 is located in the output circuit of the transistor. In the embodiment of FIG. 5, coil L is inserted in the emitter line of transistor T with one end of coil L being connected to the emitter of transistor T. One end of control coil L, is connected to the emitter of transistor T, while its other end is connected via the capacitor C to the base of transistor T. Thus, coil L, is located in the input circuit of the transistor T. The base of transistor T is also connected via the resistor R to one pole (-l-) of the supply voltage source U and the collector of the transistor T is connected to this pole direct. If the other end of coil L, is connected to the other pole of supply voltage source U, the conventional two-coil drive circuit with self-starting RC-network is obtained such as is known in principle from FIG. 1 of French Patent 1,376,358. If the balance system is at rest, this circuit, by charging capacitor C through resistor R, is capable of generating a drive current pulse in operating coil L which causes the balance system to start from standstill, because capacitor C is charged until the threshold voltage necessary to render transistor T conductive is reached.

In the embodiment of FIG. 5 there is also provided additional transistor T4, whose collector-emitter path is inserted between that end of operating coil L, which is remote from the emitter of transistor T, and the negative pole of the supply voltage source U, while its base serves as the input E for the sync signal from crystal osare the same as in the arrangement of FIG. 1, whose operation was described in connection with FIGS. 3 and 4, with the only exception that here, in the case of a positive sync signal, the current path is not turned on and off.

In the arrangement of FIG. 5 it is also, of course, possible to place the additional transistor at any other point of the two-coil drive circuit, i.e., in two-coil circuits, so that the current path to be turned on or off by the sync signal can be chosen as required.

Maintaining the principle underlying the present invention, the method in accordance with the invention can also be used in clocks with magnet systems which have a greater or smaller number of poles.

It is particularly advantageous if all electronic circuit parts are made using monolithic integrated circuit techniques. It is possible to provide both a single integrated circuit, comprising the automatic drive circuit and the frequency divider stages, in one enclosure and several individual integrated circuits in several enclosures for the individual circuit parts. In the latter case it is possible, for example, to make one part, mainly the frequency divider stages, as a monolithic integrated circuit using insulated gate field effect transistors (MOS- F et), while the other parts are made as monolithic integrated circuits using bipolar transistors. However, other distributions to MOS and bipolar techniques are possible, also.

The essential advantage of the method in accordance with this invention is that a crystal-controlled clock can be derived in a simple manner from a clock with electromagnetic balance drive by only providing an additional electronic unit comprising the crystal oscillator and the frequency divider, but without any structural changes in the movement, and that such a crystal controlled clock can be mass-produced. A synchronization range of more than :3 min/d is easy to achieve, so that even extreme changes in the natural frequency of the balance system can becorrected. Another advantage of the method in accordance with this invention is that, with the kind of synchronization in accordance with the invention, the vibration amplitude of the balance is kept constant, so that the synchronization can cause no control oscillations. In addition, the vibration amplitude of the balance system can be chosen to be large (e.g. 200), so that the torques exerted on wrist-watch balance systems due to motions of the hand or of the arm have only little effect.

While we have described above the principles of our invention in connection with specific apparatus it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. A circuit arrangement for carrying out a method of synchronizing a balance system of clocks and wristwatches having an automatic drive circuit and a given vibration frequency comprising the steps of: generating a sync signal having a given frequency, one half of said given frequency being slightly different than said given vibration frequency of said balance system; controlling by said sync signal the conduction of said drive circuit departs from one half of said given frequency the more the energy content of a primary pulse produced by said drive circuit is reduced; and producing automatically in said drive circuit a secondary pulse having the same polarity as said primary pulse as the energy content of said primary pulse is reduced, the energy content of said secondary pulse being dependent on the energy content of said primary pulse, both said primary pulse and said secondary pulse providing a constant total energy content for said drive circuit; said circuit arrangement comprising:

a circuit to produce said sync signal; a driving transistor of given conductivity type; a control transistor of a conductivity type'complementary to said given conductivity type; a balance system; a supply voltage source having a positive pole and a negative pole; a drive coil for said balance system having one end thereof coupled to one of said poles of said source;

a first resistor coupled between the other end of said drive coil and the collector of said driving transistor;

the emitter of said driving transistor being coupled to the other of said poles of said source;

a capacitor having one plate thereof coupled to said one of said poles of said source;

a second resistor coupled between the other plate of said capacitor and the junction of said drive coil and said first resistor;

the emitter of said control transistor being coupled to said other plate of said capacitor;

a third resistor and a fourth resistor coupled in series between said other of said poles of said source and the junction of said drive coil and said first and second resistors;

the base of said control transistor being coupled to the junction of said third and fourth resistors;

the collector of said control transistor being coupled to the base of said driving transistor;

an auxiliary transistor of a conductivity type complementary to said given conductivity type, the collector of said auxiliary transistor being coupled to said other of said poles of said source, the emitter of said auxiliary transistor being coupled to said other plate of said capacitor and the base of said auxiliary transistor being coupled to the junction of said driving coil and said first and second resistors; and

an additional transistor having its base coupled to said circuit to produce said sync signal and its collector-emitter path inserted at a given point in said circuit arrangement to control the conduction of said driving transistor.

2. A circuit arrangement according to claim I, wherein said collector-emitter path of said additional transistor is interposed between the base of said driving transistor and said other of said poles of said source. 3. A circuit arrangement for carrying out a method of synchronizing a balance system of clocks and wrist- 'watches having an automatic drive circuit and a given vibration frequency comprising the steps of: generating a sync signal having a given frequency, one half of said given frequency being slightly different than said given vibration frequency of said balance system; controlling by said sync signal the conduction of said drive circuit once per semi-vibration of said balance system in such a manner that the more said given vibration frequency departs from one half of said given frequency the more the energy content of a primary pulse produced by said drive circuit is reduced; and producing automatically in said drive circuit a secondary pulse having the same polarity as said primary pulse as the energy content of said primary pulse is reduced, the energy content of said secondary pulse being dependent on the energy content of said primary pulse, both said primary pulse and said secondary pulse providing a constant total energy content for said drive circuit; said circuit arrangement comprising:

a circuit to produce said sync signal; a supply voltage source having a positive pole and a negative pole; a balance system; a transistor having its collector-emitter path coupled to one of said poles of said source; an operating coil for said balance system disposed in the collector-emitter circuit of said transistor; a control coil for said balance system; a self-starting network including a resistor coupled between said one of said poles of said source and the base of said transistor, and a capacitor coupled in series with said control coil in the base-emitter circuit of said transistor; and

ing coil and the other of said poles of said source.

Claims (4)

1. A circuit arrangement for carrying out a method of synchronizing a balance system of clocks and wrist-watches having an automatic drive circuit and a given vibration frequency comprising the steps of: generating a sync signal having a given frequency, one half of said given frequency being slightly different than said given vibration frequency of said balance system; controlling by said sync signal the conduction of said drive circuit once per semi-vibration of said balance system in such a manner that the more said given vibration frequency departs from one half of said given frequency the more the energy content of a primary pulse produced by said drive circuit is reduced; and producing automatically in said drive circuit a secondary pulse having the same polarity as said primary pulse as the energy content of said primary pulse is reduced, the energy content of said secondary pulse being dependent on the energy content of said primary pulse, both said primary pulse and said secondary pulse providing a constant total energy content for said drive circuit; said circuit arrangement comprising: a circuit to produce said sync signal; a driving transistor of given conductivity type; a control transistor of a conductivity type complementary to said given conductivity type; a balance system; a supply voltage source having a positive pole and a negative pole; a drive coil for said balance system having one end thereof coupled to one of said poles of said source; a first resistor coupled between the other end of said drive coil and the collector of said driving transistor; the emitter of said driving transistor being coupled to the other of said poles of said source; a capacitor having one plate thereof coupled to said one of said poles of said source; a second resistor coupled between the other plate of said capacitor and the junction of said drive coil and said first resistor; the emitter of said control transistor being coupled to said other plate of said capacitor; a third resistor and a fourth resistor coupled in series between said other of said poles of said source and the junction of said drive coil and said first and second resistors; the base of said control transistor being coupled to the junction of said third and fourth resistors; the collector of said control transistor being coupled to the base of said driving transistor; an auxiliary transistor of a conductivity type complementary to said given conductivity type, the collector of said auxiliary transistor being coupled to said other of said poles of said source, the emitter of said auxiliary traNsistor being coupled to said other plate of said capacitor and the base of said auxiliary transistor being coupled to the junction of said driving coil and said first and second resistors; and an additional transistor having its base coupled to said circuit to produce said sync signal and its collector-emitter path inserted at a given point in said circuit arrangement to control the conduction of said driving transistor.

2. A circuit arrangement according to claim 1, wherein said collector-emitter path of said additional transistor is interposed between the base of said driving transistor and said other of said poles of said source.

3. A circuit arrangement for carrying out a method of synchronizing a balance system of clocks and wrist-watches having an automatic drive circuit and a given vibration frequency comprising the steps of: generating a sync signal having a given frequency, one half of said given frequency being slightly different than said given vibration frequency of said balance system; controlling by said sync signal the conduction of said drive circuit once per semi-vibration of said balance system in such a manner that the more said given vibration frequency departs from one half of said given frequency the more the energy content of a primary pulse produced by said drive circuit is reduced; and producing automatically in said drive circuit a secondary pulse having the same polarity as said primary pulse as the energy content of said primary pulse is reduced, the energy content of said secondary pulse being dependent on the energy content of said primary pulse, both said primary pulse and said secondary pulse providing a constant total energy content for said drive circuit; said circuit arrangement comprising: a circuit to produce said sync signal; a supply voltage source having a positive pole and a negative pole; a balance system; a transistor having its collector-emitter path coupled to one of said poles of said source; an operating coil for said balance system disposed in the collector-emitter circuit of said transistor; a control coil for said balance system; a self-starting network including a resistor coupled between said one of said poles of said source and the base of said transistor, and a capacitor coupled in series with said control coil in the base-emitter circuit of said transistor; and an additional transistor having its base coupled to said circuit to produce said sync signal and its collector-emitter path inserted at a given point in said circuit arrangement to control the conduction of said transistor.

4. A circuit arrangement according to claim 3, wherein one end of said operating coil is coupled to the emitter of said transistor, and the collector-emitter path of said additional transistor is coupled between the other end of said operating coil and the other of said poles of said source.

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