EP0764895B1 - Sound generator, in particular for time piece - Google Patents

Sound generator, in particular for time piece Download PDF

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Publication number
EP0764895B1
EP0764895B1 EP96114707A EP96114707A EP0764895B1 EP 0764895 B1 EP0764895 B1 EP 0764895B1 EP 96114707 A EP96114707 A EP 96114707A EP 96114707 A EP96114707 A EP 96114707A EP 0764895 B1 EP0764895 B1 EP 0764895B1
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EP
European Patent Office
Prior art keywords
sound generator
generator according
capacitor
current mirror
control
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP96114707A
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German (de)
French (fr)
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EP0764895A1 (en
Inventor
Rudolf Bugmann
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ETA SA Manufacture Horlogere Suisse
Ebauchesfabrik ETA AG
Original Assignee
Ebauchesfabrik ETA AG
Eta SA Fabriques dEbauches
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G13/00—Producing acoustic time signals
    • G04G13/02—Producing acoustic time signals at preselected times, e.g. alarm clocks
    • G04G13/021—Details
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/02—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos
    • G10H1/04—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation
    • G10H1/053—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation during execution only
    • G10H1/057—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation during execution only by envelope-forming circuits

Definitions

  • the present invention relates to a generator sound system comprising an acoustic system having preferably a piezoelectric element or electromagnetic as a transducer of the sounds to be produced.
  • the invention relates to a sound generator intended to generate a short melody so, for example, that it can be used as an alarm in a timepiece.
  • a sound generator of this type is known from the patent US 4,567,806.
  • the acoustic system here a sound transducer
  • a controlled current source such as a semiconductor component whose electrode command receives a melody signal composed of pulses having the frequency of the musical note to be produced and of which the amplitude is gradually decreasing during one predetermined evanescent time. This decrease is planned to improve the sound quality of the note produced and allows this quality to be compared to that of which the human ear is used to when listening of certain musical instruments.
  • the evanescence of the note produced is obtained in providing in the control circuit of the semiconductor component a capacity that is charged whenever a note must be produced and discharged during the time of production of the note that is to say to the rhythm of the frequency of this note and with amplitude pulses decreasing.
  • This form of control signal occurs naturally echoes in the main circuit of the semiconductor component and, consequently, in the sound transducer.
  • An object of the invention is to propose a generator sound of the kind briefly described above, but lacking of the disadvantages mentioned.
  • Another object of the present invention is to provide such a generator which is inexpensive and easy to achieve.
  • the subject of the invention is therefore a sound generator, especially to serve as an alarm in a room watchmaking, intended to generate sounds at amplitude variable, and including an acoustic system mounted in series with a controlled current source, the electrode control of said controlled current source being connected to a control circuit comprising a capacity and capable of providing a control signal having a frequency determining the note to be produced and having a envelope corresponding to said variable amplitude, said generator being characterized in that said circuit control also includes a programmable current mirror whose output branch supplies said control electrode, and an input branch of which is connected in series with said capacity.
  • the sound generator is intended more particularly to be incorporated as alarm generator in a wristwatch, alarm to reproduce a series of notes forming a melody.
  • the generator sound comprises a first part 1 advantageously integrated with the watch circuit on the same chip semiconductor material.
  • a second part 2 is made with discrete components for which must therefore each find room in the movement of the watch. We naturally try to reduce this place necessary as much as possible.
  • This second part 2 of the sound generator comprises an acoustic system A comprising a transducer 3, of preferably piezoelectric, connected in parallel to a self 4 which is intended, in a manner known per se, for produce an overvoltage on the transducer 3, each time applied pulse.
  • This parallel mounting of the transducer 3 and the choke 4 is connected in series with the collector-emitter path of a current source controlled, for example a bipolar transistor 5 of the type NPN, and intended as a discrete component.
  • the emitter of this bipolar transistor 5 is connected to the ground, while a battery 6 is connected between the assembly in aforementioned parallel and ground.
  • the sound transducer 3 can also be of the type electromagnetic.
  • a capacitor 7 called “envelope capacity” is connected between terminal 8 of part 1 of the sound generator and ground.
  • This part 1 comprises two other terminals by means of which it is connected to part 2.
  • One of them, referenced 9 is connected to the base of the transistor 5, while the other terminal, referenced 10, is connected to the battery positive terminal 6.
  • the latter supplies the supply potential V DD of all the functional units of part 1 of the integrated circuit.
  • the other supply potential V SS is grounded. All the power connections of these functional units are clearly shown in the diagram in FIG. 1 and they will therefore not be discussed further in the following.
  • the sound generator includes a current mirror programmable realized using MOS transistors and generally designated by the reference 11.
  • This mirror of current has an output branch 12 in which the source-drain paths are inserted, respectively drain-source of three transistors, namely a transistor M2 type P (the mirror output), a transistor M1 of P type also and an N type M3 transistor (the switches).
  • Terminal 9 is connected to the node between transistors M2 and M3 and therefore controls the electrode command, which is in the example therefore the basis, of bipolar transistor 5.
  • the output 12 of the current mirror 11 thus provides the base-emitter current of this transistor.
  • the current mirror 11 also includes three input branches 13, 14 and 15 qualified respectively of "long”, “medium” and “short” in this description for reasons that will appear in the following this one.
  • the first 13 of these input branches, the branch "long”, also includes in series the source-drain paths, drain-source respectively of three transistors, know a P type M5 transistor (the mirror input), a transistor M4, also of type P and a transistor M6 of type N (switches).
  • the gates of the transistors M1, M3 and M4 are connected to each other by forming a node 16.
  • the gates of the transistors M2 and M5 are connected to each other and also to the drain of the transistor M5.
  • the gate of transistor M6 is connected to a circuit of two inverters 17 and 18 in series, the input of which is connected to a terminal 19 called “long drive " leading outwards from this part of the integrated circuit.
  • the drain of transistor M6 is connected to a node 20, the input of the current mirror, to which terminal 8 is also connected, in other words the envelope capacity 7.
  • the middle drive branch 14 comprises the source-drain series paths of two P-type transistors M7 and M8.
  • the gate of transistor M8 is also connected to this node 20.
  • a similar arrangement is planned for branch 15 short attack and it includes the transistors M9 and M10.
  • the transistors M2, M5, M8 and M10 therefore form a mirror programmable current.
  • Programming is done using transistors M7 and M9.
  • the grids of the M1 transistors, M3 and M4 are connected to a control terminal 21 called of "melody", by means of two inverters 22 and 23 in series.
  • the gates of the transistors M7 and M9 are respectively connected to the outputs of two NAND gates 24 and 25.
  • the first inputs of these gates are connected to the output of the inverter 22.
  • the other input of the NAND gate 24 is connected to a control terminal 26 "medium attack " .
  • the other input of the NAND gate 25 is connected to the output of an inverter 27 whose input is connected to the output of a NAND gate 28.
  • a first input of the latter is connected to the terminal 26, while the other input of this door is connected to a terminal 29 "short drive".
  • the melody signal is applied to terminal 21. It can be generated for example by a counter of pulses (not shown) which successively provides pulse trains of predetermined duration and appropriate frequencies to reproduce notes from the desired melody.
  • the corresponding signal is applied via the inverters 22 and 23 on the grids of the transistors M1, M3 and M4 and through NAND gates 24, 25 on the grids of the transistors M7 and M9. Entrance and the output of the current mirror 11 are therefore activated and deactivated at the rate of these pulse trains.
  • the transistor M6 is connected to the input 20 of the current mirror 11 and is connected in parallel to the envelope capacitor 7.
  • the potential of terminal 19 can pass from the potential V DD to the potential V SS and vice versa. As long as it remains at the potential V DD , the transistor M6 is conductive, therefore the input 20 of the current mirror is forced to V SS , and the capacitor 7 is short-circuited; the envelope function is thus inhibited.
  • the terminals 26 and 29 being forced to V SS , the application of the potential V SS to the terminal 19 has the effect of rendering the transistor M6 non-conductive so that the capacitor 7, hitherto discharged, is charged by means of '' a series of current pulses flowing in the first input branch 13 of the current mirror 11. These current pulses have an amplitude varying from one pulse to another depending on the charge curve of the capacitor 7.
  • this branch 13 can be assimilated to an RC circuit, in combination with the capacitor 7.
  • the ratio of the currents that can flow in the respective branches 12 and 13 of the mirror 11 is determined by construction based on ratios dimensions of the transistors that make up the mirror.
  • the train pulses flowing into the base of the transistor bipolar 5 has an envelope of the same shape as that of the branch 13 current. This in turn is reflected in the main circuit of transistor 5 of so that transducer 3 also receives a train of identical-looking pulses.
  • the branches 14 and 15 make it possible to modify the ratio of the current mirror 11 as a function of the control signals applied to the terminals 26 and 29. For example, if the average attack is chosen by forcing the terminal 26 to the potential V DD , the branch 14 is connected in parallel to the branch 13. As a result, the ratio of the mirror and therefore also of the currents will be reduced as a function of the dimensional relationships chosen for the transistors of the three branches 12, 13 and 14 then active. You can choose a ratio of 7, for example.
  • FIG. 2 shows, by way of example, the shapes waves obtained by replacing the transducer 3 and the self 4 by the equivalent resistance of the self.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • General Physics & Mathematics (AREA)
  • Electromechanical Clocks (AREA)
  • Electric Clocks (AREA)
  • Control Of Electrical Variables (AREA)

Description

La présente invention est relative à un générateur sonore comportant un système acoustique ayant de préférence un élément piézo-électrique ou électromagnétique comme transducteur des sons à produire.The present invention relates to a generator sound system comprising an acoustic system having preferably a piezoelectric element or electromagnetic as a transducer of the sounds to be produced.

Plus particulièrement, l'invention concerne un générateur sonore destiné à engendrer une courte mélodie afin, par exemple, de pouvoir servir comme alarme dans une pièce d'horlogerie.More particularly, the invention relates to a sound generator intended to generate a short melody so, for example, that it can be used as an alarm in a timepiece.

Un générateur sonore de ce type est connu du brevet US 4 567 806. Dans cette proposition antérieure, le système acoustique, ici un transducteur sonore, est connecté en série avec une source de courant commandée telle qu'un composant semi-conducteur dont l'électrode de commande reçoit un signal de mélodie composé d'impulsions ayant la fréquence de la note musicale à produire et dont l'amplitude est progressivement décroissante pendant un temps prédéterminé d'évanescence. Cette décroissance est prévue pour améliorer la qualité sonore de la note produite et permet de rapprocher cette qualité de celle à laquelle l'oreille humaine est habituée lors de l'écoute de certains instruments musicaux.A sound generator of this type is known from the patent US 4,567,806. In this earlier proposal, the acoustic system, here a sound transducer, is connected in series with a controlled current source such as a semiconductor component whose electrode command receives a melody signal composed of pulses having the frequency of the musical note to be produced and of which the amplitude is gradually decreasing during one predetermined evanescent time. This decrease is planned to improve the sound quality of the note produced and allows this quality to be compared to that of which the human ear is used to when listening of certain musical instruments.

L'évanescence de la note produite est obtenue en prévoyant dans le circuit de commande du composant semi-conducteur une capacité qui est chargée chaque fois qu'une note doit être produite et déchargée pendant le temps de production de la note c'est-à-dire au rythme de la fréquence de cette note et avec des impulsions d'amplitude décroissante. Cette forme de signal de commande se répercute naturellement dans le circuit principal du composant semi-conducteur et, par voie de conséquence, dans le transducteur sonore.The evanescence of the note produced is obtained in providing in the control circuit of the semiconductor component a capacity that is charged whenever a note must be produced and discharged during the time of production of the note that is to say to the rhythm of the frequency of this note and with amplitude pulses decreasing. This form of control signal occurs naturally echoes in the main circuit of the semiconductor component and, consequently, in the sound transducer.

Ce circuit connu donne satisfaction sur le plan de la qualité sonore des mélodies engendrées et est d'une réalisation relativement simple. Elle se prête donc de ce point de vue assez bien à l'utilisation dans les pièces d'horlogerie et en particulier dans les montres-bracelets.This known circuit gives satisfaction in terms of sound quality of the melodies generated and is of relatively simple realization. It therefore lends itself to this pretty good point of view for use in rooms of watchmaking and in particular in wristwatches.

Cette réalisation antérieure présente cependant un inconvénient qui est lié à son utilisation dans une montre-bracelet en particulier, dans laquelle le faible encombrement des pièces qui la composent est primordial. Or, si la plupart des. composants du générateur sonore peuvent faire partie du circuit intégré de la montre assurant aussi la fonction de garde-temps et d'autres fonctions qui y sont liées, il n'en est pas de même du transducteur sonore, du composant semi-conducteur et également de la capacité qui est réalisée habituellement à l'aide d'un condensateur dont la valeur peut aller jusqu'à 6,8µF. Ces composants ne pouvant être intégrés, ils doivent individuellement trouver une place dans le mouvement de la montre et le condensateur en question, compte tenu de sa valeur élevée, en prend beaucoup.This earlier achievement, however, presents a drawback which is linked to its use in a wristwatch in particular, in which the weak size of the parts that make it up is essential. However, if most of. sound generator components can be part of the integrated circuit of the watch also performing the function of timepieces and others related functions, it is not the same for sound transducer, semiconductor component and also of the capacity which is usually carried out at using a capacitor whose value can go up to 6.8µF. Since these components cannot be integrated, they must individually find a place in the watch movement and the capacitor in question, given its high value, takes a lot.

Un but de l'invention est de proposer un générateur sonore du genre décrit brièvement ci-dessus, mais dépourvu des inconvénients mentionnés.An object of the invention is to propose a generator sound of the kind briefly described above, but lacking of the disadvantages mentioned.

Un autre but de la présente invention est de proposer un tel générateur qui est peu coûteux et facile à réaliser.Another object of the present invention is to provide such a generator which is inexpensive and easy to achieve.

L'invention a donc pour objet un générateur sonore, notamment pour servir d'alarme dans une pièce d'horlogerie, destiné à générer des sons à amplitude variable, et comprenant un système acoustique monté en série avec une source de courant commandée, l'électrode de commande de ladite source de courant commandée étant connecté à un circuit de commande comprenant une capacité et capable de fournir un signal de commande ayant une fréquence déterminant la note à produire et ayant une enveloppe correspondant à ladite amplitude variable, ledit générateur étant caractérisé en ce que ledit circuit de commande comporte en outre un miroir de courant programmable dont la branche de sortie alimente ladite électrode de commande, et dont une branche d'entrée est montée en série avec ladite capacité.The subject of the invention is therefore a sound generator, especially to serve as an alarm in a room watchmaking, intended to generate sounds at amplitude variable, and including an acoustic system mounted in series with a controlled current source, the electrode control of said controlled current source being connected to a control circuit comprising a capacity and capable of providing a control signal having a frequency determining the note to be produced and having a envelope corresponding to said variable amplitude, said generator being characterized in that said circuit control also includes a programmable current mirror whose output branch supplies said control electrode, and an input branch of which is connected in series with said capacity.

D'autres caractéristiques et avantages de l'invention apparaítront au cours de la description qui va suivre, donnée uniquement à titre d'exemple et faite en se référant aux dessins annexés sur lesquels :

  • la figure 1 est un schéma d'un générateur sonore selon l'invention; et
  • la figure 2 est un graphique de tension V en fonction du temps t pour illustrer l'évolution du signal sonore produit par le générateur selon l'invention, afin de faire entendre une note musicale, le système acoustique du générateur sonore étant remplacé par une résistance de charge.
Other characteristics and advantages of the invention will become apparent during the description which follows, given solely by way of example and made with reference to the appended drawings in which:
  • Figure 1 is a diagram of a sound generator according to the invention; and
  • FIG. 2 is a graph of voltage V as a function of time t to illustrate the evolution of the sound signal produced by the generator according to the invention, in order to hear a musical note, the acoustic system of the sound generator being replaced by a resistor dump.

On va se référer à la figure 1 qui représente le mode de réalisation préféré de l'invention.We will refer to Figure 1 which represents the mode preferred embodiment of the invention.

Dans cet exemple, le générateur sonore est destiné plus particulièrement à être incorporé en tant que générateur d'alarme dans une montre-bracelet, l'alarme devant reproduire une suite de notes formant une mélodie.In this example, the sound generator is intended more particularly to be incorporated as alarm generator in a wristwatch, alarm to reproduce a series of notes forming a melody.

Dans le mode de réalisation représenté, le générateur sonore comporte une première partie 1 avantageusement intégré avec le circuit de la montre sur une même puce de matériau semi-conducteur. Une seconde partie 2 est réalisée avec des composants discrets pour lesquels on doit donc chacun trouver de la place dans le mouvement de la montre. On cherche naturellement à réduire cette place nécessaire dans toute la mesure du possible.In the embodiment shown, the generator sound comprises a first part 1 advantageously integrated with the watch circuit on the same chip semiconductor material. A second part 2 is made with discrete components for which must therefore each find room in the movement of the watch. We naturally try to reduce this place necessary as much as possible.

Cette seconde partie 2 du générateur sonore comprend un système acoustique A comportant un transducteur 3, de préférence piézo-électrique, connecté en parallèle à une self 4 qui est destinée, de façon connue en soi, à produire une surtension sur le transducteur 3, à chaque impulsion appliquée. Ce montage en parallèle du transducteur 3 et de la self 4 est relié en série avec le trajet collecteur-émetteur d'une source de courant commandée, par exemple un transistor bipolaire 5 de type NPN, et prévu sous la forme d'un composant discret. L'émetteur de ce transistor bipolaire 5 est connecté à la masse, tandis qu'une pile 6 est reliée entre le montage en parallèle précité et la masse. Il est à noter que le transducteur sonore 3 peut également être du type électromagnétique.This second part 2 of the sound generator comprises an acoustic system A comprising a transducer 3, of preferably piezoelectric, connected in parallel to a self 4 which is intended, in a manner known per se, for produce an overvoltage on the transducer 3, each time applied pulse. This parallel mounting of the transducer 3 and the choke 4 is connected in series with the collector-emitter path of a current source controlled, for example a bipolar transistor 5 of the type NPN, and intended as a discrete component. The emitter of this bipolar transistor 5 is connected to the ground, while a battery 6 is connected between the assembly in aforementioned parallel and ground. It should be noted that the sound transducer 3 can also be of the type electromagnetic.

Un condensateur 7 dit "capacité d'enveloppe" est connecté entre la borne 8 de la partie 1 du générateur sonore et la masse. Cette partie 1 comprend deux autres bornes au moyen desquelles elle est reliée à la partie 2. L'une d'elle, référencée 9 est reliée à la base du transistor 5, tandis que l'autre borne, référencée 10, est connectée à la borne positive de la pile 6. Cette dernière fournit le potentiel VDD d'alimentation de toutes les unités fonctionnelles de la partie 1 du circuit intégré. L'autre potentiel d'alimentation VSS est à la masse. Toutes les connexions d'alimentation de ces unités fonctionnelles apparaissent clairement sur le schéma de la figure 1 et elles ne seront donc pas commentées davantage dans ce qui va suivre.A capacitor 7 called "envelope capacity" is connected between terminal 8 of part 1 of the sound generator and ground. This part 1 comprises two other terminals by means of which it is connected to part 2. One of them, referenced 9 is connected to the base of the transistor 5, while the other terminal, referenced 10, is connected to the battery positive terminal 6. The latter supplies the supply potential V DD of all the functional units of part 1 of the integrated circuit. The other supply potential V SS is grounded. All the power connections of these functional units are clearly shown in the diagram in FIG. 1 and they will therefore not be discussed further in the following.

Selon une caractéristique essentielle de l'invention, le générateur sonore comporte un miroir de courant programmable réalisé à l'aide de transistors MOS et désigné globalement par la référence 11. Ce miroir de courant comporte une branche de sortie 12 dans laquelle sont insérés les trajets source-drain, respectivement drain-source de trois transistors, à savoir un transistor M2 de type P (la sortie du miroir), un transistor M1 de type P également et un transistor M3 de type N (les interrupteurs). La borne 9 est connectée au noeud entre les transistors M2 et M3 et commande donc l'électrode de commande, qui est dans l'exemple donc la base, du transistor bipolaire 5. La sortie 12 du miroir de courant 11 fournit ainsi le courant base-émetteur de ce transistor.According to an essential characteristic of the invention, the sound generator includes a current mirror programmable realized using MOS transistors and generally designated by the reference 11. This mirror of current has an output branch 12 in which the source-drain paths are inserted, respectively drain-source of three transistors, namely a transistor M2 type P (the mirror output), a transistor M1 of P type also and an N type M3 transistor (the switches). Terminal 9 is connected to the node between transistors M2 and M3 and therefore controls the electrode command, which is in the example therefore the basis, of bipolar transistor 5. The output 12 of the current mirror 11 thus provides the base-emitter current of this transistor.

Le miroir de courant 11 comprend également trois branches d'entrée 13, 14 et 15 qualifiées respectivement de "longue", "moyenne" et "courte" dans la présente description pour des raisons qui apparaítront dans la suite de celle-ci.The current mirror 11 also includes three input branches 13, 14 and 15 qualified respectively of "long", "medium" and "short" in this description for reasons that will appear in the following this one.

La première 13 de ces branches d'entrée, la branche "longue", comporte également en série les trajets source-drain, respectivement drain-source de trois transistors, à savoir un transistor M5 de type P (l'entrée du miroir), un transistor M4, également de type P et un transistor M6 de type N (les interrupteurs).The first 13 of these input branches, the branch "long", also includes in series the source-drain paths, drain-source respectively of three transistors, know a P type M5 transistor (the mirror input), a transistor M4, also of type P and a transistor M6 of type N (switches).

Les grilles des transistors M1, M3 et M4 sont connectées l'une à l'autre en formant un noeud 16. Les grilles des transistors M2 et M5 sont reliées l'une à l'autre et également au drain du transistor M5. La grille du transistor M6 est connectée à un montage de deux inverseurs 17 et 18 en série dont l'entrée est reliée à une borne 19 dite "d'attaque longue" menant vers l'extérieur de cette partie du circuit intégré. Le drain du transistor M6 est relié à un noeud 20, l'entrée du miroir de courant, auquel est également connectée la borne 8, autrement dit la capacité d'enveloppe 7.The gates of the transistors M1, M3 and M4 are connected to each other by forming a node 16. The gates of the transistors M2 and M5 are connected to each other and also to the drain of the transistor M5. The gate of transistor M6 is connected to a circuit of two inverters 17 and 18 in series, the input of which is connected to a terminal 19 called "long drive " leading outwards from this part of the integrated circuit. The drain of transistor M6 is connected to a node 20, the input of the current mirror, to which terminal 8 is also connected, in other words the envelope capacity 7.

La branche 14 d'attaque moyenne comprend les trajets en série source-drain de deux transistors M7 et M8 de type P. La source du transistor M7 et au potentiel VDD, tandis que le drain du transistor M8 est raccordé au noeud 20. La grille du transistor M8 est également connectée à ce noeud 20.The middle drive branch 14 comprises the source-drain series paths of two P-type transistors M7 and M8. The source of the transistor M7 and at the potential V DD , while the drain of the transistor M8 is connected to the node 20. The gate of transistor M8 is also connected to this node 20.

Un montage analogue est prévu pour la branche 15 d'attaque courte et il comporte les transistors M9 et M10. Les transistors M2, M5, M8 et M10 forment donc un miroir de courant programmable. La programmation se fait à l'aide des transistors M7 et M9. Les grilles des transistors M1, M3 et M4 sont raccordées à une borne de commande 21 dite de "mélodie", par l'intermédiaire de deux inverseurs 22 et 23 en série.A similar arrangement is planned for branch 15 short attack and it includes the transistors M9 and M10. The transistors M2, M5, M8 and M10 therefore form a mirror programmable current. Programming is done using transistors M7 and M9. The grids of the M1 transistors, M3 and M4 are connected to a control terminal 21 called of "melody", by means of two inverters 22 and 23 in series.

Les grilles des transistors M7 et M9 sont connectées respectivement aux sorties de deux portes NON-ET 24 et 25. Les premières entrées de ces portes sont reliées à la sortie de l'inverseur 22. L'autre entrée de la porte NON-ET 24 est connectée à une borne de commande 26 "d'attaque moyenne". L'autre entrée de la porte NON-ET 25 est reliée à la sortie d'un inverseur 27 dont l'entrée est connectée à la sortie d'une porte NON-ET 28. Une première entrée de cette dernière est connectée à la borne 26, tandis que l'autre entrée de cette porte est reliée à une borne 29 "d'attaque courte".The gates of the transistors M7 and M9 are respectively connected to the outputs of two NAND gates 24 and 25. The first inputs of these gates are connected to the output of the inverter 22. The other input of the NAND gate 24 is connected to a control terminal 26 "medium attack " . The other input of the NAND gate 25 is connected to the output of an inverter 27 whose input is connected to the output of a NAND gate 28. A first input of the latter is connected to the terminal 26, while the other input of this door is connected to a terminal 29 "short drive".

Le fonctionnement de ce générateur sonore est le suivant.The operation of this sound generator is the following.

Le signal de mélodie est appliqué à la borne 21. Il peut être engendré par exemple par un compteur d'impulsions (non représenté) qui fournit successivement des trains d'impulsions de durée prédéterminée et de fréquences appropriées pour reproduire les notes de la mélodie souhaitée. Le signal correspondant est appliqué via les inverseurs 22 et 23 sur les grilles des transistors M1, M3 et M4 et à travers des portes NON-ET 24, 25 sur les grilles des transistors M7 et M9. L'entrée et la sortie du miroir de courant 11 sont donc activées et désactivées au rythme de ces trains d'impulsions.The melody signal is applied to terminal 21. It can be generated for example by a counter of pulses (not shown) which successively provides pulse trains of predetermined duration and appropriate frequencies to reproduce notes from the desired melody. The corresponding signal is applied via the inverters 22 and 23 on the grids of the transistors M1, M3 and M4 and through NAND gates 24, 25 on the grids of the transistors M7 and M9. Entrance and the output of the current mirror 11 are therefore activated and deactivated at the rate of these pulse trains.

Par ailleurs, le transistor M6 est connecté à l'entrée 20 du miroir de courant 11 et est branché en parallèle sur le condensateur d'enveloppe 7. Le potentiel de la borne 19 peut passer du potentiel VDD au potentiel VSS et inversement. Tant qu'elle reste au potentiel VDD, le transistor M6 est conducteur, donc l'entrée 20 du miroir de courant est forcée à VSS, et le condensateur 7 est court-circuité; la fonction d'enveloppe est ainsi inhibée. Les bornes 26 et 29 étant forcées à VSS, l'application du potentiel VSS à la borne 19 a pour effet de rendre le transistor M6 non-conducteur de sorte que le condensateur 7, jusqu'ici déchargé, se charge au moyen d'une suite d'impulsions de courant s'écoulant dans la première branche d'entrée 13 du miroir de courant 11. Ces impulsions de courant ont une amplitude variant d'une impulsion à l'autre en fonction de la courbe de charge du condensateur 7. Ainsi, cette branche 13 est assimilable à un circuit RC, en combinaison avec le condensateur 7.Furthermore, the transistor M6 is connected to the input 20 of the current mirror 11 and is connected in parallel to the envelope capacitor 7. The potential of terminal 19 can pass from the potential V DD to the potential V SS and vice versa. As long as it remains at the potential V DD , the transistor M6 is conductive, therefore the input 20 of the current mirror is forced to V SS , and the capacitor 7 is short-circuited; the envelope function is thus inhibited. The terminals 26 and 29 being forced to V SS , the application of the potential V SS to the terminal 19 has the effect of rendering the transistor M6 non-conductive so that the capacitor 7, hitherto discharged, is charged by means of '' a series of current pulses flowing in the first input branch 13 of the current mirror 11. These current pulses have an amplitude varying from one pulse to another depending on the charge curve of the capacitor 7. Thus, this branch 13 can be assimilated to an RC circuit, in combination with the capacitor 7.

Cependant, le rapport des courants pouvant s'écouler dans les branches respectives 12 et 13 du miroir 11 est déterminé par construction en fonction des rapports dimensionnels des transistors qui composent le miroir. En d'autres termes, l'enveloppe du train d'impulsions de courant s'établissant dans la branche de sortie 12 va suivre celle du train d'impulsions qui charge le condensateur 7. Cela a pour conséquence que le train d'impulsions s'écoulant dans la base du transistor bipolaire 5 présente une enveloppe de la même forme que celle du courant de la branche 13. Ceci a son tour se répercute dans le circuit principal du transistor 5 de sorte que le transducteur 3 reçoit également un train d'impulsions d'allure identique.However, the ratio of the currents that can flow in the respective branches 12 and 13 of the mirror 11 is determined by construction based on ratios dimensions of the transistors that make up the mirror. In in other words, the envelope of the pulse train of current established in the output branch 12 va follow that of the pulse train which charges the capacitor 7. This means that the train pulses flowing into the base of the transistor bipolar 5 has an envelope of the same shape as that of the branch 13 current. This in turn is reflected in the main circuit of transistor 5 of so that transducer 3 also receives a train of identical-looking pulses.

Il en résulte en définitive une évanescence de la note produite par le transducteur 3 en fonction de la courbe de charge du condensateur 7.This ultimately results in an evanescence of the note produced by the transducer 3 as a function of the capacitor charge curve 7.

On notera toutefois qu'à chaque impulsion, l'intensité du courant de charge du condensateur 7 peut avoir une valeur proportionnellement plus faible par rapport à l'intensité du courant de base du transistor 5, en fonction du rapport du miroir 11. De la sorte, pour fixer une courbe de charge donnée, on peut utiliser un condensateur dont la capacité, comparée à celle du condensateur utilisé dans la technique antérieure, peut être réduite dans le même rapport.Note, however, that with each pulse, the intensity of the charging current of the capacitor 7 can have a proportionately lower value by relation to the intensity of the base current of transistor 5, depending on the ratio of the mirror 11. So, for fix a given load curve, we can use a capacitor whose capacity, compared to that of capacitor used in the prior art, can be reduced in the same report.

Pour fixer les idées, si dans le montage antérieur du brevet américain précité, on doit prévoir un condensateur de 6,8 µF et si, d'autre part, on choisit le rapport de courants du miroir 11 égal à 14 par exemple, on peut se contenter d'un condensateur 7 d'une valeur d'environ 480 nF. On comprend que de ce fait et grâce aux caractéristiques de l'invention, le condensateur étant nettement plus petit, on a besoin de beaucoup moins de place pour le loger. En outre, son prix de revient est nettement plus faible.To fix the ideas, if in the previous assembly of the aforementioned US patent, a capacitor must be provided 6.8 µF and if, on the other hand, the ratio of mirror currents 11 equal to 14 for example, we can content with a capacitor 7 worth around 480 nF. We understand that because of this and thanks to characteristics of the invention, the capacitor being significantly smaller, we need a lot less place to house it. In addition, its cost price is significantly lower.

Les branches 14 et 15 permettent de modifier le rapport du miroir de courant 11 en fonction des signaux de commande appliqués aux bornes 26 et 29. Par exemple, si on choisit l'attaque moyenne en forçant la borne 26 au potentiel VDD, la branche 14 vient se connecter en parallèle à la branche 13. De ce fait, le rapport du miroir et donc aussi des courants va se réduire en fonction des relations dimensionnelles choisies pour les transistors des trois branches 12, 13 et 14 alors actives. On peut choisir un rapport de 7, par exemple.The branches 14 and 15 make it possible to modify the ratio of the current mirror 11 as a function of the control signals applied to the terminals 26 and 29. For example, if the average attack is chosen by forcing the terminal 26 to the potential V DD , the branch 14 is connected in parallel to the branch 13. As a result, the ratio of the mirror and therefore also of the currents will be reduced as a function of the dimensional relationships chosen for the transistors of the three branches 12, 13 and 14 then active. You can choose a ratio of 7, for example.

Cet effet peut être cumulé si on force également la borne 29 au potentiel VDD, moyennant quoi, les trois branches 13, 14 et 15 sont mises en parallèle et forment l'entrée du miroir de courant 11. On peut ainsi obtenir un rapport de courants encore plus réduit par exemple de 4,7 environ.This effect can be cumulated if the terminal 29 is also forced to the potential V DD , whereby the three branches 13, 14 and 15 are put in parallel and form the input of the current mirror 11. It is thus possible to obtain a ratio of currents even more reduced for example by about 4.7.

La figure 2 montre, à titre d'exemple, les formes d'ondes obtenues en remplaçant le transducteur 3 et la self 4 par la résistance équivalente de la self. Les courbes A, B et C représentent respectivement les cas d'attaques "longue", "moyenne" et "courte" à partir d'un instant t=T d'application des signaux d'attaque sur les bornes respectives 19, 26 et 29. Le signal mélodie est appliqué à la borne 21 à partir du temps t=0. Ces courbes ont été obtenues avec les valeurs de rapport de courant et de capacité du condensateur 7 telles qu'indiquées ci-dessus.Figure 2 shows, by way of example, the shapes waves obtained by replacing the transducer 3 and the self 4 by the equivalent resistance of the self. The curves A, B and C respectively represent the cases "long", "medium" and "short" attacks from a instant t = T of application of the attack signals on the respective terminals 19, 26 and 29. The melody signal is applied to terminal 21 from time t = 0. These curves were obtained with the current ratio values and capacitance of the capacitor 7 as indicated above.

Bien qu'un mode de réalisation du générateur selon l'invention soit décrit ci-dessus, l'invention n'est pas limitée à ce mode de réalisation spécifique, lequel est donné uniquement à titre d'exemple non-limitatif de l'invention.Although an embodiment of the generator according to the invention is described above, the invention is not limited to this specific embodiment, which is given only as a non-limiting example of the invention.

Claims (9)

  1. Sound generator, in particular for use as an alarm in a timepiece, intended to generate sounds of variable amplitude and comprising an acoustic system (A) connected in series with a controlled current source (5), a control electrode (9) of said controlled current source (5) being connected to a control circuit (1, 7) comprising a capacitor (7) and which is capable of providing a control signal having a frequency which determines the note to be produced and having an envelope corresponding to said variable amplitude, said generator being characterized in that said control circuit (1, 7) further comprises a programmable current mirror (11) the output branch (12) of which supplies said control electrode (9) and an input branch (13) of which is connected in series with said capacitor (7).
  2. Sound generator according to claim 1, characterized in that said controlled current source (5) is a bipolar transistor.
  3. Sound generator according to claim 1 or 2, characterized in that said capacitor (7) is connected in parallel to switching means (M6) intended to inhibit the envelope of said control signal.
  4. Sound generator according to any one of the claims 1 to 3, characterized in that said control circuit (1, 7) comprises switching means (M1, M3) connected to a control terminal (21) for generating at the output of said current mirror (11) a control signal having said frequency of said note to be produced.
  5. Sound generator according to any one of the preceding claims, characterized in that said current mirror (11) comprises at least a second input branch (14, 15) and control means (M7, M9) for allowing a selective parallel connection of said second input branch (14, 15) with the first input branch (13).
  6. Sound generator according to any one of the preceding claims, characterized in that said current mirror (11) is realized by way of an integrated circuit comprising MOS transistors (M1 to M10).
  7. Sound generator according to any one of the preceding claims, characterized in that said acoustic system (A) comprises a transducer (3) connected in parallel with a coil (4).
  8. Sound generator according to the preceding claim, characterized in that said transducer (3) is of the piezoelectric type.
  9. Sound generator according to any one of the preceding claims, characterized in that said control circuit (1, 7) comprises switching means (M4, M7, M9) arranged so as to avoid a charging of said capacitor (7) during the inactive phases of said current mirror (11).
EP96114707A 1995-09-21 1996-09-13 Sound generator, in particular for time piece Expired - Lifetime EP0764895B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH2669/95 1995-09-21
CH02669/95A CH689243B5 (en) 1995-09-21 1995-09-21 sound generator, especially for a timepiece.

Publications (2)

Publication Number Publication Date
EP0764895A1 EP0764895A1 (en) 1997-03-26
EP0764895B1 true EP0764895B1 (en) 1999-04-21

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EP96114707A Expired - Lifetime EP0764895B1 (en) 1995-09-21 1996-09-13 Sound generator, in particular for time piece

Country Status (9)

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US (1) US5668783A (en)
EP (1) EP0764895B1 (en)
JP (1) JP4037930B2 (en)
CA (1) CA2186069A1 (en)
CH (1) CH689243B5 (en)
DE (1) DE69602146T2 (en)
HK (1) HK1013691A1 (en)
SG (1) SG63663A1 (en)
TW (1) TW317630B (en)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4236437A (en) * 1979-03-26 1980-12-02 Kimball International, Inc. Organ brass pulse keyer
JPS57211087A (en) * 1981-06-22 1982-12-24 Seiko Instr & Electronics Ltd Boosting circuit of electronic timepiece element
JPS5946691A (en) * 1982-09-09 1984-03-16 セイコーエプソン株式会社 Sound generation circuit
US4796503A (en) * 1987-06-15 1989-01-10 Industrial Technology Research Institute Amplification circuit for electronic tone generator
US5493543A (en) * 1994-11-07 1996-02-20 Timex Corporation Capacitive charge pump driver circuit for piezoelectric alarm

Also Published As

Publication number Publication date
CH689243B5 (en) 1999-07-15
DE69602146D1 (en) 1999-05-27
SG63663A1 (en) 1999-03-30
JP4037930B2 (en) 2008-01-23
US5668783A (en) 1997-09-16
CH689243GA3 (en) 1999-01-15
JPH09127269A (en) 1997-05-16
DE69602146T2 (en) 1999-11-18
TW317630B (en) 1997-10-11
HK1013691A1 (en) 1999-09-03
CA2186069A1 (en) 1997-03-22
EP0764895A1 (en) 1997-03-26

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