US3688154A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Astable multivibrator circuit with means for ensuring proper starting of oscillations
Assignee: RCA Licensing Corp
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Filing: 1970-05-11
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Granted: 1972-08-29
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Expires: 1990-05-11
Abstract
Abstract In an astable multivibrator circuit, a diode operates in conjunction with a voltage supply derived from the multivibrator output signal to insure the initiation of oscillations by limiting base drive current to the multivibrator transistors when power is first applied. This prevents saturation of both transistors and ensures sufficient loop gain to initiate oscillations in response to an unbalance in the system. As power is first applied, the diode is non-conductive and a relatively low voltage is applied to bias the multivibrator transistors. During normal operation, the voltage derived from the multivibrator output signal causes the diode to conduct, thereby coupling the base circuits to the operating potential supply. While conductive, the diode forward voltage drop compensates for changes in the Vbe of the transistors due to temperature variations and tends to maintain a constant charging current for the base circuits.
Inventors
- 👤 Todd J Christopher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:26
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/26; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/62; H03K4/64; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/18
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
119 words
In a multivibrator circuit including a pair of transistors, each having base, emitter and collector electrodes, a first biasing circuit path having resistance connected between the base electrodes of said transistors and an operating potential supply terminal, switch means connected between the base electrodes of said transistors and said operating potential supply terminal, means for deriving a control voltage in response to an output signal from said multivibrator, and means for applying said control voltage to said switch means to actuate said switch means to the closed position to provide a second biasing path between the base electrodes of said transistors and said operating potential supply terminal, said second biasing path having a lower resistance than said first path.
Claim 2
Dependent Claim
119 words
In a multivibrator circuit including a pair of transistors, each having base, emitter and collector electrodes, a first biasing circuit path having resistance connected between the base electrodes of said transistors and an operating potential supply terminal, switch means connected between the base electrodes of said transistors and said operating potential supply terminal, means for deriving a control voltage in response to an output signal from said multivibrator, and means for applying said control voltage to said switch means to actuate said switch means to the closed position to provide a second biasing path between the base electrodes of said transistors and said operating potential supply terminal, said second biasing path having a lower resistance than said first path.
Claim 3
Dependent Claim
27 words
A circuit as defined in claim 1 wherein said first biasing circuit provides a biasing current of low enough value to keep said transistors out of saturation.
Claim 4
Dependent Claim
24 words
A circuit as defined in claim 2 wherein said switch means comprises a semiconductor diode connected to be forward biased by said control voltage.
Claim 5
Dependent Claim
134 words
In a multivibrator circuit including at least two transistors and base bias resistors associated with said transistors, a circuit comprising: means providing a first biasing path including said base biasing resistors, a power supply for providing an operating potential to said multivibrator, circuit means coupled to said multivibrator and responsive to signals from said multivibrator to develop a first input signal in the presence of oscillation signals from said multivibrator and a second output signal in the absence of said oscillation signals, and switching means coupled from said power supply to said base bias resistors and to said circuit means, said switching means responsive to said first output signal from said circuit means to couple said base bias resistors to said power supply for providing a second biasing path for said base biasing resistors.
Claim 6
Dependent Claim
134 words
In a multivibrator circuit including at least two transistors and base bias resistors associated with said transistors, a circuit comprising: means providing a first biasing path including said base biasing resistors, a power supply for providing an operating potential to said multivibrator, circuit means coupled to said multivibrator and responsive to signals from said multivibrator to develop a first input signal in the presence of oscillation signals from said multivibrator and a second output signal in the absence of said oscillation signals, and switching means coupled from said power supply to said base bias resistors and to said circuit means, said switching means responsive to said first output signal from said circuit means to couple said base bias resistors to said power supply for providing a second biasing path for said base biasing resistors.
Claim 7
Dependent Claim
43 words
A circuit as defined in claim 4 wherein said circuit means comprises a voltage supply which supplies a first voltage in the absence of oscillations and a second voltage greater than said first voltage in the presence of oscillations from said multivibrator circuit.
Claim 8
Dependent Claim
132 words
In a multivibrator circuit including at least two transistors and base bias reSistors associated with said transistors, a circuit comprising: a power supply for providing an operating potential to said multivibrator: a voltage supply comprising a rectifier circuit coupled to a horizontal output stage of a television receiver at a point to receive flyback pulses during a retrace interval of each horizontal deflection cycle for supplying a relatively low voltage in the absence of oscillations and a relatively high voltage in the presence of oscillations from said multivibrator circuit; and unidirectional conducting means coupled from said power supply to said base bias resistors and to said voltage supply, said unidirectional conducting means responsive to said relatively high voltage from said voltage supply to couple said base bias resistors to said power supply.
Claim 9
Dependent Claim
132 words
In a multivibrator circuit including at least two transistors and base bias reSistors associated with said transistors, a circuit comprising: a power supply for providing an operating potential to said multivibrator: a voltage supply comprising a rectifier circuit coupled to a horizontal output stage of a television receiver at a point to receive flyback pulses during a retrace interval of each horizontal deflection cycle for supplying a relatively low voltage in the absence of oscillations and a relatively high voltage in the presence of oscillations from said multivibrator circuit; and unidirectional conducting means coupled from said power supply to said base bias resistors and to said voltage supply, said unidirectional conducting means responsive to said relatively high voltage from said voltage supply to couple said base bias resistors to said power supply.
Claim 10
Dependent Claim
139 words
In a multivibrator circuit including at least two transistors and base bias resistors associated with said transistors, a circuit comprising: a first power supply for providing an operating potential to said multivibrator; a second power supply; means including a first unidirectional conducting device coupled to said multivibrator and to said second power supply and responsive to signals from said multivibrator to develop a first output signal in the presence of oscillation signals from said multivibrator and a second output signal in the absence of said oscillation signals; and switching means comprising a diode rectifier having a cathode terminal coupled to said first power supply and an anode terminal coupled to said base bias resistors associated with said multivibrator transistors and further coupled to said means including a first unidirectional conducting device and being responsive to said first output signal.
Claim 11
Dependent Claim
139 words
In a multivibrator circuit including at least two transistors and base bias resistors associated with said transistors, a circuit comprising: a first power supply for providing an operating potential to said multivibrator; a second power supply; means including a first unidirectional conducting device coupled to said multivibrator and to said second power supply and responsive to signals from said multivibrator to develop a first output signal in the presence of oscillation signals from said multivibrator and a second output signal in the absence of said oscillation signals; and switching means comprising a diode rectifier having a cathode terminal coupled to said first power supply and an anode terminal coupled to said base bias resistors associated with said multivibrator transistors and further coupled to said means including a first unidirectional conducting device and being responsive to said first output signal.
Claim 12
Dependent Claim
136 words
An oscillator circuit comprising: first and second electron devices coupled together in an astable multivibrator configuration, each said device having a control element and said second device having an output terminal, a power supply for providing an operating potential to said multivibrator, biasing means coupled through a first biasing path to said control elements, means coupled to said output terminal for providing a first voltage level in response to astable operation of said multivibrator and for providing a second voltage level in response to the absence of said astable operation, and switching means coupled from said power supply to said biasing means and to said means for providing first and second voltage levels, said switching means responsive to said first voltage level to couple said power supply to said biasing means through a second biasing path.
Claim 13
Dependent Claim
136 words
An oscillator circuit comprising: first and second electron devices coupled together in an astable multivibrator configuration, each said device having a control element and said second device having an output terminal, a power supply for providing an operating potential to said multivibrator, biasing means coupled through a first biasing path to said control elements, means coupled to said output terminal for providing a first voltage level in response to astable operation of said multivibrator and for providing a second voltage level in response to the absence of said astable operation, and switching means coupled from said power supply to said biasing means and to said means for providing first and second voltage levels, said switching means responsive to said first voltage level to couple said power supply to said biasing means through a second biasing path.
Claim 14
Dependent Claim
126 words
An astable multivibrator circuit including first and second transistors each having base, collector and emitter terminals, and further including: a power supply for providing operating current to said multivibrator, biasing resistors coupled to each of said base terminals and having their remote terminals coupled to a common junction point, a voltage supply coupled to said common junction point, said supply being responsive to signals from said multivibrator for providing a bias voltage to said biasing resistors in the absence of astable operation of said multivibrator circuit and for providing a higher voltage level in response to astable operation, and switching means coupled from said power supply to said junction point and responsive to said higher voltage level to couple said power supply to said biasing resistors.
Claim 15
Dependent Claim
126 words
An astable multivibrator circuit including first and second transistors each having base, collector and emitter terminals, and further including: a power supply for providing operating current to said multivibrator, biasing resistors coupled to each of said base terminals and having their remote terminals coupled to a common junction point, a voltage supply coupled to said common junction point, said supply being responsive to signals from said multivibrator for providing a bias voltage to said biasing resistors in the absence of astable operation of said multivibrator circuit and for providing a higher voltage level in response to astable operation, and switching means coupled from said power supply to said junction point and responsive to said higher voltage level to couple said power supply to said biasing resistors.
Claim 16
Dependent Claim
19 words
A circuit as defined in claim 9 wherein said bias voltage maintains said transistors in their non-saturated conduction region.
Claim 17
Dependent Claim
124 words
In a television receiver, a horizontal output stage in which flyback pulses are developed during a retrace portion of each deflection cycle, a horizontal oscillator coupled to said output stage, said oscillator having two transistors arranged in an astable multivibrator configuration including base biasing means, a voltage supply coupled to said horizontal output stage for developiNg a first output voltage in the absence of said flyback pulses, and responsive to the presence of said flyback pulses for developing a higher output voltage, impedance means coupling said voltage supply to said base biasing means, a power supply for providing operating current to said horizontal oscillator, and switching means responsive to said presence of flyback pulses for coupling said power supply to said base biasing means.
Claim 18
Dependent Claim
124 words
In a television receiver, a horizontal output stage in which flyback pulses are developed during a retrace portion of each deflection cycle, a horizontal oscillator coupled to said output stage, said oscillator having two transistors arranged in an astable multivibrator configuration including base biasing means, a voltage supply coupled to said horizontal output stage for developiNg a first output voltage in the absence of said flyback pulses, and responsive to the presence of said flyback pulses for developing a higher output voltage, impedance means coupling said voltage supply to said base biasing means, a power supply for providing operating current to said horizontal oscillator, and switching means responsive to said presence of flyback pulses for coupling said power supply to said base biasing means.
Claim 19
Dependent Claim
45 words
A circuit as defined in claim 11 wherein said first voltage developed by said voltage supply biases said transistors in their non-saturated conduction region, and wherein said power supply output is sufficient to bias said transistors in their saturation region of conduction during astable operation.
Claim 20
Dependent Claim
17 words
A circuit as defined in claim 11 wherein said impedance means includes at least a resistance element.
Claim 21
Dependent Claim
14 words
A circuit as defined in claim 11 wherein said switching means comprises a diode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |