US3727151A - Integrated circuit for electronic timepieces - Google Patents
Integrated circuit for electronic timepieces Download PDFInfo
- Publication number
- US3727151A US3727151A US00244644A US24464472A US3727151A US 3727151 A US3727151 A US 3727151A US 00244644 A US00244644 A US 00244644A US 24464472 A US24464472 A US 24464472A US 3727151 A US3727151 A US 3727151A
- Authority
- US
- United States
- Prior art keywords
- capacitor
- transistor
- resistor
- value
- fork
- Prior art date
- 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.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
- G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
- G04C3/08—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a mechanical oscillator other than a pendulum or balance, e.g. by a tuning fork, e.g. electrostatically
- G04C3/10—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a mechanical oscillator other than a pendulum or balance, e.g. by a tuning fork, e.g. electrostatically driven by electromagnetic means
- G04C3/108—Driving circuits
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N97/00—Electric solid-state thin-film or thick-film devices, not otherwise provided for
Definitions
- ABSTRACT An integrated electronic circuit operating in conjunction with an electromagnetic transducer for sustaining a tuning fork in vibration, the fork serving as a frequency standard for a timepiece.
- the electronic circuit includes a super-gain transistor whose output is connected through an external power source to the drive coil of the transducer associated with the tuning fork to produce current pulses for actuating the fork.
- the voltage induced in the phase-sensing coil of the transducer is applied to the input of the transistor through a coupling capacitor, a resistor providing base current for the transistor, whereby regeneration occurs to sustain oscillation at a rate determined by the resonance frequency of the fork.
- the capacitor has a value in the picofarad range, this small value being offset by a large resistor value, in excess of 100 megohms, the resultant decrease in base current being compensated for by an increase in current gain effected by the super-gain transistor.
- the capacitor, the resistor and the transistor are fabricated as a monolithic device, making possible a miniature timepiece construction.
- This invention relates generally to electronically controlled timepieces provided with an electro-mechanical resonator as a frequency standard, and more particularly to an integrated circuit for such timepieces.
- each electromagnetic transducer is associated produce current pulses in the drive coil for magneti-- callyatituating the tines.
- the electronic circuit functions essentially as afeedback oscillator, the rate of feedback being governed by the frequency of the mechanical resonator.
- the electronic circuit in a tuning-fork timepiece of the above-described type is that of a resonant feedback oscillator which differs from a conventional electronic oscillator in that in place of an inductance-capacitance combination, an equivalent electro-mechanical resonator is used.
- balance wheel being sustained in oscillation by the cuits for the purpose of miniaturizing the electronic circuit of electronic timepieces employing mechanical resonators.
- a p-type wafer or silicon as a substrate.
- An epitaxial layer of n material is grown on the surface of the wafer, and integrated circuit components are made by using a masking technique to permit successive diffusions of alternating p and n materials into the epitaxial layer.
- Transistors are made by using three of the layers in an 'n-p-n or a p-n-p sandwichydiodes are made by using two of the layers or by properly connecting transistors to form diodes.
- a layer of silicon dioxide exists over the surface of the' wafer. This layer serves to protect or passivate the integrated circuit so that it will not be contaminated by its environment.
- Resistors are generally obtained by using a diffused layer in which current is forced to flow in a direction parallel to the p-n junction thus formed, or by depositelectronic circuit. And while mechanical resonators are capacitor, and-s resistor. When a battery-operated electronic timepiece is designed to beconfined within a watch casing or in "a miniature housing of similar dimensions where space is at spremium, the use of microelectronics technology to reducethe size and cost of the electronic circuit wouldsppear to be in order. But. for the reasons to be now explained, it has not heretofore been possible to fullyexploit integrated ciring thin films of resistive material on the top of the silicon dioxide layer. Capacitors are obtained by using pn junction capacitances or by depositing conducting material above the silicon dioxide layer. Connections between components are made by depositing a conducting material over the oxide and using a masking technique to select desired areas.
- MOS capacitors can be made in the picofarad range to be used primarily for decoupling and by-pass capacitors.
- MOS metal-oxide-silicon
- the metal-oxide-silicon (MOS) capacitor is formed by an n lregion (emitter diffusion) and a metal film usually of aluminum separated by a silicon dioxide dielectric.
- the terminal performance requirements of integrated circuits are such that capacitors made in a single crystal monolithic circuit are unacceptable, because the proper values cannot be obtained,becausevariations with temperature are too large or because of parasitics which cannot be tolerated.
- one can use a thin film technique for forming the capacitor in which event the bottom plate is made by depositing an aluminum layer on the final S, 0, layer of themonolithic structure. Next one deposits a layer of dielectric material over the aluminum layer, above which goes another'layer of aluminum to produce the top plate of the capacitor. But here too, the largest values obtainable on chips are in the picofarad range.
- the primary object of this invention to provide a solid state electronic-circuit operable in conjunction with an electromagneticallyactuated tuning fork or other mechanical resonator for sustaining the resonator in vibration at its natural frequency, the circuit being constituted by components all of which lend themselves to fabrication in a monolithic device. Because the capacitor has a value in the picofarad range, it may be fabricated by thin film, M08 or diffusion techniques, and the need for a hybrid deviceis obviated.
- a significant feature of the invention resides in the fact that when'the tuning fork functions as a frequency standard or time base for a timepiece,.the highly compact integrated circuit makes possible greater miniaturization of the timepiece than has heretofore been feasible. Essentially the same arrangementmay be used to produce tuning-fork tone generators, filters and other low-frequency devices-employing a mechanical resonator as a frequency-determining element.
- a resistor whose value exceeds 100 megohms to provide base current for the transistor, whereby regeneration occurs in the amplifier to sustain oscillation at a rate detennined by the resonance frequency of the fork;
- the small value of the capacitor is offset by a large resistor value-(exceeding 100 megohms), as a consequence of which the resultant base current is extremely low, But compensation for the low level of base current is effected by the super-gain transistor which produces output current at a level sufficient to actuate the fork. Because the picofard capacitor, the megohm resistor and the super-gain transistor all lend themselves to integrated circuit fabrication, the electronic circuit may be produced in the form of a tiny chip.
- FIG. 1 is a schematic diagram of a tuning-fork frequency standard, including an integrated circuit in accordance with the invention
- FIG. 2 is the equivalent electrical circuit of the tuning fork and its associated electronic circuit in simplified form
- FIG. 3 is a schematic circuit showing in another form, the simplified electronic circuit associated with the equivalent circuit of the fork.
- FIG. 1 there is shown a frequency standard employing a tuning fork 10 having a pair of flexible tines 10A and 10B, and a mounting'stem 11.
- the vibratory action of the fork is converted into rotary motion for operating the hands by means 'of a suitable motion transformer.
- a suitable motion transformer This may be in the'formof an indexing mechanism or by means'of a magnetic escapement.
- the tuning fork oscillations may be used to provide periodic electrical pulses to activate an electronic time display.
- Tuning fork 10 is provided with electromagnetic drive and phase-sensing transducers, the first being.
- an integrated circuit chip Associated with the electromagnetic transducers is an integrated circuit chip, generally designated by numeral 16, .the circuit thereof being formed by a transistor 17 having base B, collector C and emitter E electrodes, a capacitor 18 and a resistor 19.
- Capacitor 18 is connected in series with resistor 19, the junction thereof being connected to base B of the transistor. The other end of capacitor 18 is connected to chip terminal T The other end of resistor 19 is connected to collector C and to chip terminal T Emitter E is connected to chip terminal T Thus, to install the chip in the tuning fork watch, only three connections thereto are required.
- Terminal T is connected to one end of phase-sensing coil which is connected in series with drive coil 13. The junction of the two coils is connected to terminal T Terminal T is connected in series with a DC power supply or battery to the other end of drive coil 13.
- This transistor which is an amplifier, has its output connected through battery 20 to drive coil 13.
- transistor 17 When transistor 17 is rendered momentarily conductive, a current pulse from the battery is delivered to the drive coil 13, the resultant magnetic field producing a thrust on tine magnet 12, thereby actuating the fork.
- the voltage induced by tine magnet 14 in phase-sensing coil 15 is applied through capacitor 18 to base B of the transistor to overcome the bias thereon resulting from base current flow through resistor 19, to control the instant or phase position, in the course of each vibratory cycle, when the drive pulse is to be delivered to the drive coil.
- the tuning fork and its associated electronic circuit fall into the resonant-feedback class of useful transistor oscillators, this class being analyzed in detail in the Transistor Manual Seventh Edition (1964), published by the General Electric Company.
- the resonant feedback oscillator uses either inductance-capacitance resonators or their electromechanical equivalent.
- the output of the transistor acting as an amplifier is coupled to the tuned primary of a transistor whose secondary is connected to the input to provide regeneration or positive feedback, causing the'amplifier to oscillate.
- the output of the transistor acting as an amplifier is coupled to the tuned primary of a transistor whose secondary is connected to the input to provide regeneration or positive feedback, causing the'amplifier to oscillate.
- the resonant feedback oscillator is a Hartley circuitin which the series-connected phase and drive coil windings form an autotransformer in place of the tw winding transformers of the standard circuit.
- the electrical equivalent to the tuning fork 10 is represented by inductance L,, capacitance C,, and resistance R;, all being in parallel relation to provide a parallel-resonant circuit whose frequency is determined by reactive values of inductance and capacitance, and whose Q is determined by the value of resistance. Since the tuning fork is a medium 0 device, as compared, say, to a high Q resonator such as a piezoelectric crystal, the value of resistance is significant.
- Resistor 19 has a value R which appears between collector C and base B
- capacitor 18 has a value C presented between base B and emitter E.
- the symbol to represents the angular frequency of the fork, that is 211- multiplied by the frequency of the fork.
- resistance R is the main determinant of the base current of the transistor, and since the transistor is a current amplifying device, the decrease in base current resulting from an increase in the value of resistance R, will, in the case of a standard transistor of the type heretofore used in electronic timepieces, not provide sufficient current in the collector output circuit to drive the tuning fork. This collector current supplies the energy sustaining the fork in vibration, and
- super-gain transistors also known commercially as super-beta transistors
- super-beta transistors are standard bipolar transistors which have emitters that have been diffused for extremely high currents.
- the D-C current gain (Beta) is inversely related to the base width. But as the emitter is diffused deeper into the base region, the beta increases to several thousands. Typical current gains of 5,000 are obtainable at one microampere collector currents.
- An integrated circuit chip adapted for association with the electromagnetic transducer of an electromechanical resonator to sustain the resonator in vibration at its natural frequency, said transducer having a drive and a phase-sensing coil, said chip being constituted by a super-gain transistor, a capacitor having a value in the picofarad range and a resistor in the megohm range, the input of said transistor being connectable through said capacitor to said' phase-sensing coil and the output thereof being connectable through an external powersource to said drivecoil, said resistor being connected between said input and output of said transistor; said transistor, said capacitor and said resistor being fabricated to define monolithic structure.
- An integrated circuit chip adapted for association with the electromagnetic transducer of an electromechanical resonator to sustain said resonator in vibration at its natural frequency, said transducer having a drive coil and a phase sensing coil, said chip compris- A. a super-gain transistor having a base, an emitter and a collector, I 1,
- C. means to connect said emitter and collector to said drive coil through an external power source whereby when said transistor is conductive, the resultant pulse actuates said resonator
- E. means to connect said phase-sensing coil between said base and said emitter through said capacitor whereby the voltage induced in said phase-sensing coil by the vibrating resonator is applied between said baseand emitter, and I a resistor connected between said base and collector to produce base current, said capacitor having a small value in the picofarad range, said resistor having a large value in the megohm range which is sufficiently large to offset the small value of the capacitor, said transistor having a gain sufficiently great to offset the small base current resulting from the use of the large value resistor; said transistor, said capacitor and said resistor being fabricated to define a monolithic structure.
- tuning fork is provided with a permanent magnet on each true, one cooperating with said drive coil and the other with said phase-sensing coil.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Oscillators With Electromechanical Resonators (AREA)
- Electric Clocks (AREA)
Priority Applications (11)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00244644A US3727151A (en) | 1972-04-17 | 1972-04-17 | Integrated circuit for electronic timepieces |
CA158,500A CA964869A (en) | 1972-04-17 | 1972-12-08 | Integrated circuit chip for electronic timepiece |
GB5893972A GB1416728A (en) | 1972-04-17 | 1972-12-20 | Resonator drive circuits for time measuring devices |
NL727217397A NL150240B (nl) | 1972-04-17 | 1972-12-20 | Oscillator voor een meetinstrument, zoals een elektronisch uurwerk. |
CH1885672A CH556052A (de) | 1972-04-17 | 1972-12-27 | |
ES410071A ES410071A1 (es) | 1972-04-17 | 1972-12-27 | Un fragmento de circuito integrado para relojes electroni- cos. |
JP48004343A JPS4919932A (de) | 1972-04-17 | 1972-12-28 | |
DE2263813A DE2263813C3 (de) | 1972-04-17 | 1972-12-28 | Erregerschaltung für einen elektromechanischen Resonator |
FR7246672A FR2180640B1 (de) | 1972-04-17 | 1972-12-28 | |
IT33981/72A IT973247B (it) | 1972-04-17 | 1972-12-29 | Piastrina a circuito integrato per un orologio elettronic |
HK566/76*UA HK56676A (en) | 1972-04-17 | 1976-09-16 | Improvements in or relating to resonator drive circuits for time measuring devices |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00244644A US3727151A (en) | 1972-04-17 | 1972-04-17 | Integrated circuit for electronic timepieces |
Publications (1)
Publication Number | Publication Date |
---|---|
US3727151A true US3727151A (en) | 1973-04-10 |
Family
ID=22923573
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00244644A Expired - Lifetime US3727151A (en) | 1972-04-17 | 1972-04-17 | Integrated circuit for electronic timepieces |
Country Status (11)
Country | Link |
---|---|
US (1) | US3727151A (de) |
JP (1) | JPS4919932A (de) |
CA (1) | CA964869A (de) |
CH (1) | CH556052A (de) |
DE (1) | DE2263813C3 (de) |
ES (1) | ES410071A1 (de) |
FR (1) | FR2180640B1 (de) |
GB (1) | GB1416728A (de) |
HK (1) | HK56676A (de) |
IT (1) | IT973247B (de) |
NL (1) | NL150240B (de) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4001869A (en) * | 1975-06-09 | 1977-01-04 | Sprague Electric Company | Mos-capacitor for integrated circuits |
US4006584A (en) * | 1974-11-14 | 1977-02-08 | Citizen Watch Co., Ltd. | Electronic timepiece |
US4110640A (en) * | 1975-04-28 | 1978-08-29 | Kabushiki Kaisha Daini Seikosha | Standard signal generating apparatus |
US5214279A (en) * | 1990-07-26 | 1993-05-25 | Fuji Photo Film Co., Ltd. | Scanning microscope and tuning fork scanning mechanism for varying the width over which a sample is scanned |
WO2011101547A1 (en) * | 2010-02-22 | 2011-08-25 | Vti Technologies Oy | Improved micromechanical resonator |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS51138064U (de) * | 1975-04-28 | 1976-11-08 |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3421309A (en) * | 1966-06-13 | 1969-01-14 | Bulova Watch Co Inc | Unitized tuning fork vibrator |
-
1972
- 1972-04-17 US US00244644A patent/US3727151A/en not_active Expired - Lifetime
- 1972-12-08 CA CA158,500A patent/CA964869A/en not_active Expired
- 1972-12-20 NL NL727217397A patent/NL150240B/xx unknown
- 1972-12-20 GB GB5893972A patent/GB1416728A/en not_active Expired
- 1972-12-27 CH CH1885672A patent/CH556052A/xx unknown
- 1972-12-27 ES ES410071A patent/ES410071A1/es not_active Expired
- 1972-12-28 FR FR7246672A patent/FR2180640B1/fr not_active Expired
- 1972-12-28 JP JP48004343A patent/JPS4919932A/ja active Pending
- 1972-12-28 DE DE2263813A patent/DE2263813C3/de not_active Expired
- 1972-12-29 IT IT33981/72A patent/IT973247B/it active
-
1976
- 1976-09-16 HK HK566/76*UA patent/HK56676A/xx unknown
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3421309A (en) * | 1966-06-13 | 1969-01-14 | Bulova Watch Co Inc | Unitized tuning fork vibrator |
Non-Patent Citations (1)
Title |
---|
Electronic Design 8, pg. 112, Apr. 11, 1968. * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4006584A (en) * | 1974-11-14 | 1977-02-08 | Citizen Watch Co., Ltd. | Electronic timepiece |
US4110640A (en) * | 1975-04-28 | 1978-08-29 | Kabushiki Kaisha Daini Seikosha | Standard signal generating apparatus |
US4001869A (en) * | 1975-06-09 | 1977-01-04 | Sprague Electric Company | Mos-capacitor for integrated circuits |
US5214279A (en) * | 1990-07-26 | 1993-05-25 | Fuji Photo Film Co., Ltd. | Scanning microscope and tuning fork scanning mechanism for varying the width over which a sample is scanned |
WO2011101547A1 (en) * | 2010-02-22 | 2011-08-25 | Vti Technologies Oy | Improved micromechanical resonator |
US20110210800A1 (en) * | 2010-02-22 | 2011-09-01 | Vti Technologies Oy | Micromechanical resonator |
CN102762954A (zh) * | 2010-02-22 | 2012-10-31 | Vti技术有限公司 | 改进的微机械共振器 |
US8723611B2 (en) | 2010-02-22 | 2014-05-13 | Murata Electronics Oy | Micromechanical resonator |
CN102762954B (zh) * | 2010-02-22 | 2015-11-25 | 村田电子有限公司 | 改进的微机械共振器 |
Also Published As
Publication number | Publication date |
---|---|
JPS4919932A (de) | 1974-02-21 |
NL7217397A (de) | 1973-10-19 |
FR2180640A1 (de) | 1973-11-30 |
IT973247B (it) | 1974-06-10 |
FR2180640B1 (de) | 1977-04-08 |
HK56676A (en) | 1976-09-24 |
NL150240B (nl) | 1976-07-15 |
DE2263813B2 (de) | 1978-04-13 |
DE2263813C3 (de) | 1978-11-23 |
ES410071A1 (es) | 1976-04-01 |
CH556052A (de) | 1974-11-15 |
GB1416728A (en) | 1975-12-03 |
DE2263813A1 (de) | 1973-10-25 |
CA964869A (en) | 1975-03-25 |
CH1885672A4 (de) | 1974-05-15 |
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