US3755751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High voltage solid-state amplifier having temperature responsive shutdown
Assignee: Motorola Solutions Inc
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Filing: 1971-10-21
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Granted: 1973-08-28
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Expires: 1991-10-21
Abstract
Abstract The amplifier circuit includes first and second output stages which respectively amplify positive and negative excursions of an input signal. A bias circuit connected to each stage prevents crossover distortion. A plurality of dependent current sources supplying the bias and amplifier stages are controlled by a master current source. Transistors having temperature responsive threshold voltages are thermally connected to each of the output stages and electrically connected between a constant bias supply and the master current source. If the temperature of either output stage increases above a predetermined value, the thermally associated transistor conducts and renders all of the current sources inoperative. Furthermore, diode strings are utilized to provide low base resistances and other transistors are utilized to provide high emitter resistances for selected transistors thereby enabling them to sustain high voltages.
Inventors
- 👤 C Ring
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:23
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3083; H03F1/00; H03F1/52
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
297 words
In an amplifier circuit having first electron control means connected to a current source, said first electron control means dissipating substantial amounts of electrical power in response to a drive current from the current source, which power dissipation tends to raise the temperature of the first electron control means above a predetermined value, the current source having control terminals, a protection circuit for limiting the temperature of said first electron control means to the predetermined value including in combination: second electron control means having first, second and control electrodes which in response to a temperature sensitive threshold voltage between its first and control electrodes changes from a non-conductive state to a conductive state between its first and second electrodes, said threshold voltage decreasing with increasing temperature, and said first eleCtron control means and said second electron control means being thermally coupled with each other to cause said second electron control means to have a temperature which increases with an increase in the temperature of said first electron control means; first circuit means coupling said first and second electrodes of said second electron control means between the control terminals of the current source; and bias circuit means connected between and providing a constant bias voltage between said first and said control electrodes of said second electron control means which has a magnitude that is less than said threshold voltage which corresponds to temperatures of said first electron control means which are less than said predetermined temperature, said constant bias voltage causing said second electron control means to change from said nonconductive state to said conductive state in response to the predetermined temperature of the first electron control means to thereby render the current source inoperative before the temperature of the first electron control means exceeds the predetermined value.
Claim 2
Dependent Claim
297 words
In an amplifier circuit having first electron control means connected to a current source, said first electron control means dissipating substantial amounts of electrical power in response to a drive current from the current source, which power dissipation tends to raise the temperature of the first electron control means above a predetermined value, the current source having control terminals, a protection circuit for limiting the temperature of said first electron control means to the predetermined value including in combination: second electron control means having first, second and control electrodes which in response to a temperature sensitive threshold voltage between its first and control electrodes changes from a non-conductive state to a conductive state between its first and second electrodes, said threshold voltage decreasing with increasing temperature, and said first eleCtron control means and said second electron control means being thermally coupled with each other to cause said second electron control means to have a temperature which increases with an increase in the temperature of said first electron control means; first circuit means coupling said first and second electrodes of said second electron control means between the control terminals of the current source; and bias circuit means connected between and providing a constant bias voltage between said first and said control electrodes of said second electron control means which has a magnitude that is less than said threshold voltage which corresponds to temperatures of said first electron control means which are less than said predetermined temperature, said constant bias voltage causing said second electron control means to change from said nonconductive state to said conductive state in response to the predetermined temperature of the first electron control means to thereby render the current source inoperative before the temperature of the first electron control means exceeds the predetermined value.
Claim 3
Dependent Claim
27 words
The combination of claim 1 wherein the first and said second electron control means respectively are first and second transistors each having emitter, collector and base electrodes.
Claim 4
Dependent Claim
213 words
The combination of claim 2 wherein said bias circuit means includes: power supply means providing a direct-current voltage of a first magnitude between first and second output terminals thereof; zener diode means having a first terminal connected to said second output terminal of said power supply means and a second terminal, said zener diode means providing a resistance of a first magnitude between its first and second terminals; second circuit means connecting said first power supply output terminal to said second terminal of said zener diode; a third transistor having a base electrode connected to said second terminal of said zener diode, a collector-electrode coupled to said first power supply output terminal, and an emitter electrode, the collector-to-base breakdown voltage of the third transistor being about equal to said first magnitude; first resistive means connected from said emitter electrode of said third transistor to said base electrode of said second transistor; and second resistive means connected from said base electrode of said second transistor to said second output terminal of said power supply means, said first resistive means having a relatively high magnitude as compared to said zener diode resistance of a first magnitude so that said third transistor can withstand said output voltage of the power supply means across its collector-to-emitter electrodes.
Claim 5
Dependent Claim
294 words
An amplifier circuit having a first electron control means which dissipates electrical power that tends to raise its temperature, the amplifier circuit including in combination: a first current source with a second electron control means having first, second and control electrodes which allows current to flow through said first electron control means in response to a bias level between said first and control electrodes of said second electron control means; first bias circuit means connected between said control and said first electrodes of said second electron control means for developing and applying said bias level therebetween; third electron control means having first, second and control electrodes, said third electron control means being responsive to a temperature dependent threshold voltage between said first and control electrodes thereof to be rendered conductive between said first and second electrodes thereof, said first and second electrodes of said third electron control means being connected across said first bias circuit means; heat conductive means thermally connecting the first electron control means to said third electron control means; and second bias circuit means connected between and providing a bias voltage of a fixed mAgnitude between said first and control electrodes of said third electron control means which is less than the threshold voltage corresponding to a predetermined temperature of the first electron control means, said threshold voltage of said third electron control means decreasing as the temperature of the first electron control means increases so that the threshold voltage of said third electron control means is reduced to said fixed magnitude of the bias voltage causing said third electron control means to be rendered conductive to remove said bias from said second electron control means and thereby rendering said first current source inoperative to protect the first electron control means.
Claim 6
Dependent Claim
294 words
An amplifier circuit having a first electron control means which dissipates electrical power that tends to raise its temperature, the amplifier circuit including in combination: a first current source with a second electron control means having first, second and control electrodes which allows current to flow through said first electron control means in response to a bias level between said first and control electrodes of said second electron control means; first bias circuit means connected between said control and said first electrodes of said second electron control means for developing and applying said bias level therebetween; third electron control means having first, second and control electrodes, said third electron control means being responsive to a temperature dependent threshold voltage between said first and control electrodes thereof to be rendered conductive between said first and second electrodes thereof, said first and second electrodes of said third electron control means being connected across said first bias circuit means; heat conductive means thermally connecting the first electron control means to said third electron control means; and second bias circuit means connected between and providing a bias voltage of a fixed mAgnitude between said first and control electrodes of said third electron control means which is less than the threshold voltage corresponding to a predetermined temperature of the first electron control means, said threshold voltage of said third electron control means decreasing as the temperature of the first electron control means increases so that the threshold voltage of said third electron control means is reduced to said fixed magnitude of the bias voltage causing said third electron control means to be rendered conductive to remove said bias from said second electron control means and thereby rendering said first current source inoperative to protect the first electron control means.
Claim 7
Dependent Claim
37 words
The amplifier circuit of claim 4 wherein said first bias circuit means includes; a zener diode connected to said control electrode of said second electron control means; and a second current source connected to said zener diode.
Claim 8
Dependent Claim
247 words
The amplifier circuit of claim 4 wherein said second bias circuit means includes: power supply means providing a direct-current voltage between first and second output terminals; zener diode means providing a first resistance between its anode and cathode, said anode being connected to said second output terminal of said power supply means; first circuit means connecting said first power supply output terminal to said cathode of said zener diode means; fourth electron control means having a first electrode, a control electrode connected to said cathode of said zener diode, and a second electrode coupled to said first power supply output terminal, said fourth electron control means requiring a relatively low resistance between its control electrode and said second power supply output terminal as compared to between its first electrode and said second output terminal to withstand said direct-current voltage across its first and second electrodes; first resistive means having a second resistance connected from said first electrode of said fourth transistor means to said control electrode of said third electron control means; and second resistive means having a third resistance connected from said control electrode of said third electron control means to said second terminal of said power supply means, said second and third resistances having a sum of a relatively high value as compared to said first resistance of said zener diode means so that said fourth electron control means can withstand said direct-current voltage of the power supply means across its first and second electrodes.
Claim 9
Dependent Claim
33 words
The amplifier circuit of claim 6 wherein said second, third and fourth electron control means are transistors and said first, second and control electrodes respectively indicate the emitter, collector and base electrodes thereof.
Claim 10
Dependent Claim
26 words
The amplifier circuit of claim 6 wherein said first circuit means includes a series circuit formed by first and second diodes and a third resistive means.
Claim 11
Dependent Claim
136 words
A high voltage amplifier circuit for increasing the electrical power of signals applied to its input terminal, including in combination: first circuit means for applying a supply voltage between supply and reference terminals thereof; transistor means having first, second and control electrodes, said transistor means requiring a relatively low resistance from said control electrode to said reference terminal as compared to a high resistance between said first electrode and said reference terminal to sustain a predetermined supply voltage between said first and second electrodes; conductive means connecting said second electrode to said supply terminal; diode means connected from said control electrode to said reference terminal, said diode means being arranged to provide said relatively low resistance between said control electrode and said reference terminal; and second circuit means connecting said first electrode to said reference terminal.
Claim 12
Dependent Claim
136 words
A high voltage amplifier circuit for increasing the electrical power of signals applied to its input terminal, including in combination: first circuit means for applying a supply voltage between supply and reference terminals thereof; transistor means having first, second and control electrodes, said transistor means requiring a relatively low resistance from said control electrode to said reference terminal as compared to a high resistance between said first electrode and said reference terminal to sustain a predetermined supply voltage between said first and second electrodes; conductive means connecting said second electrode to said supply terminal; diode means connected from said control electrode to said reference terminal, said diode means being arranged to provide said relatively low resistance between said control electrode and said reference terminal; and second circuit means connecting said first electrode to said reference terminal.
Claim 13
Dependent Claim
42 words
The high voltage amplifier of claim 9 wherein said second circuit means includes electron control means connected between said first electrode and said reference terminal for providing said high resistance between said first electrode of said transistor means and said reference terminal.
Claim 14
Dependent Claim
27 words
The high voltage amplifier of claim 10 wherein said transistor means and said electron control means each include a pair of transistors connected in a Darlington configuration.
Claim 15
Dependent Claim
289 words
A high voltage amplifier circuit having a first input terminal and an output terminal which is connected to the first terminal of a load which also has a second terminal, the amplifier increasing the power of a first signal applied at the first input terminal and including in combination: a current source providing a substantially constant current at its output terminal in response to a voltage applied to the bias terminal thereof; first circuit means having a first terminal which is connected to said bias terminal of said current source and a reference terminal which is connected to the second load terminal, said first circuit means being adapted to apply a first supply voltage between said bias and reference terminals; first electron control means having first, second and control terminals, said first terminal being coupled to the output terminal of the amplifier; second circuit means coupling said control terminal to said output of said current source and to the first input terminal; first transistor means having first, second and control electrodes, said first electrode being connected to said second terminal of said first electron control means, said control electrode being connected to said output of said current source, and said second electrode being connected to said first terminal of said first circuit means; first diode means connected between said control electrode of said first transistor means and said amplifier output terminal; and said first electron control means providing a relatively high impedance at said first electrode of said first transistor means as compared to the low impedance provided by said first diode means at said control electrode of said first transistor means to enable said first transistor means to withstand high voltages between said first and second electrodes thereof.
Claim 16
Dependent Claim
289 words
A high voltage amplifier circuit having a first input terminal and an output terminal which is connected to the first terminal of a load which also has a second terminal, the amplifier increasing the power of a first signal applied at the first input terminal and including in combination: a current source providing a substantially constant current at its output terminal in response to a voltage applied to the bias terminal thereof; first circuit means having a first terminal which is connected to said bias terminal of said current source and a reference terminal which is connected to the second load terminal, said first circuit means being adapted to apply a first supply voltage between said bias and reference terminals; first electron control means having first, second and control terminals, said first terminal being coupled to the output terminal of the amplifier; second circuit means coupling said control terminal to said output of said current source and to the first input terminal; first transistor means having first, second and control electrodes, said first electrode being connected to said second terminal of said first electron control means, said control electrode being connected to said output of said current source, and said second electrode being connected to said first terminal of said first circuit means; first diode means connected between said control electrode of said first transistor means and said amplifier output terminal; and said first electron control means providing a relatively high impedance at said first electrode of said first transistor means as compared to the low impedance provided by said first diode means at said control electrode of said first transistor means to enable said first transistor means to withstand high voltages between said first and second electrodes thereof.
Claim 17
Dependent Claim
82 words
The high voltage amplifier of claim 12 wherein said first electron control means includes: first and second transistors each having emitter, base and collector electrodes, said emitter electrode of said first transistor being connected to said base electrode of said second transistor, said collector electrodes of said first and second transistors being connected together to form said second terminal, said base electrode of said first transistor forming said control terminal, and said emitter electrode of said second transistor forming said first terminal.
Claim 18
Dependent Claim
84 words
The high voltage amplifier of claim 13 further including: first resistive means connected between said emitter electrode of said second transistor and said amplifier output terminal; and second diode means connected between said base electrode of said first transistor and said output terminal so that when the current through said first resistive means exceeds a predetermined amount, the voltage thereacross tends to forward bias said second diode means to thereby limit the current through said first transistor means and said first and second transistors.
Claim 19
Dependent Claim
103 words
The high voltage amplifier of claim 12 wherein: said first transistor means includes third and fourth transistors each having emitter, base and collector electrodes; said base electrode of said third transistor forming said control electrode, said collector electrodes of said third and fourth transistors being connected together to form said second electrode, and said emitter electrode of said fourth transistor forming said first electrode of said first transistor means; said emitter electrode of said third transistor being connected to said base electrodes of said fourth transisTor; and second resistive means connecting said base electrode of said fourth transistor to said first diode means.
Claim 20
Dependent Claim
38 words
The power amplifier of claim 12 wherein the first signal has a first polarity and said first supply voltage also has said first polarity with respect to the potential at said reference terminal of said first circuit means.
Claim 21
Dependent Claim
228 words
The high voltage amplifier circuit of claim 12 for also increasing the power of a second signal applied at a second input terminal further including in combination: third circuit means adapted for applying a second supply voltage between first and reference output terminals, said reference output terminal being connected to the second terminal of the load; second electron control means having first, second and control terminals, said first terminal being coupled to said first terminal of said third circuit means; fourth circuit means coupling said control terminal of said second electron control means to the second input terminal; second transistor means having first, second and control electrodes, said first electrode being connected to said second terminal of said second electron control means, said control electrode being connected to said output of said current source, and said second electrode being coupled to said output terminal of the amplifier; third diode means connected between said control electrode of said second transistor means and said first terminal of said third circuit means; and said second electron control means providing a relatively high impedance at said first electrode of said second transistor means as compared to the low impedance provided by said third diode means at said control electrode of said second transistor means to enable said second transistor means to withstand voltages of high amplitude between its first and second electrodes.
Claim 22
Dependent Claim
94 words
The high voltage amplifier of claim 17 wherein said second electron control means includes: fifth and sixth transistors each having emitter, base and collector electrodes, said emitter electrode of said fifth transistor being connected to said base electrode of said sixth transistor, said collector electrodes of said fifth and sixth transistors being connected together to form said second terminal of said second electron control means, said base electrode of said fifth transistor forming said control terminal and said emitter electrode of said sixth transistor forming said first terminal of said second electron control means.
Claim 23
Dependent Claim
92 words
The high voltage amplifier of claim 18 further including: third resistive means connected between said emitter electrode of said sixth transistor and said first terminal of said third circuit means; and fourth diode means connected between said base electrode of said fifth transistor and said first terminal of said third circuit means so that when the current through said third resistive means exceeds a predetermined amount, the voltage thereacross tends to forward bias said fourth diode means to limit the current through said second transistor means and said fifth and sixth transistors.
Claim 24
Dependent Claim
103 words
The high voltage amplifier of claim 17 wherein: said second transistor means includes seventh and eighth transistors each having emitter, base and collector electrodes; said base electrode of said seventh transistor forming said control electrode, said collector electrodes of said seventh and eighth transistors being connected together to form said second electrode, and said emitter electrode of said eighth transistor forming said first electrode of said second transistor means; said emitter electrode of said seventh transistor being connected to said base electrode of said eighth transistor; and fourth resistive means connecting said base electrode of said eighth transistor to said third diode means.
Claim 25
Dependent Claim
120 words
The high voltage amplifier circuit of claim 17 further including: bias circuit means having first and second output terminals respectively connected to said first and second amplifier input terminals and a first bias terminal connected to said output of said current source, and a second bias terminal coupled to said first terminal of said third circuit means; fifth circuit means connected between said first output terminal of said bias circuit and said first bias terminal for providing a bias voltage of said first polarity to said first electron control means; and sixth circuit means connected between said second bias terminal and said second output terminal for providing a bias voltage of said second polarity to said second electron control means.
Claim 26
Dependent Claim
102 words
The high voltage amplifier circuit of claim 17 wherein: said current source includes first, second and third current source transistors each having emitter, base and collector electrodes; fifth, sixth and seventh resistive means respectively connecting the emitter electrodes of said first, second and third current source transistors to said first terminal of said first circuit means; seventh circuit means connecting the base electrodes of said first, second and third current source transistors together; and eighth circuit means respectively connecting said collector electrodes of said first, second and third current source transistors to form a plurality of output terminals for said current source.
Claim 27
Dependent Claim
207 words
The high voltage amplifier circuit of claim 22 further including: a first current regulating transistor with emitter, collector and base electrodes, said base electrode of said first current regulating transistor being connected to said base electrodes of said first, second and third current source transistors; eighth resistive means connecting said emitter electrode of said first current regulating transistor to said first terminal of said first circuit means; a second current regulating transistor having its emitter electrode connected to said base electrode of said first current regulating transistor, its collector electrode connected to said first terminal of said third circuit means, and a base electrode connected to said collector electrode of said first current regulating transistor; a master current control transistor having emitter, base and collector electrodes; ninth circuit means connecting said collector electrode of said master current control transistor to said collector electrode of said first current regulating transistor; tenth circuit means connecting said emitter electrode of said master current control transistor to said first electrode of said third circuit means; and first bias circuit means for applying a substantially constant voltage between the base-to-emitter of said master current control transistor so that said first, second and third current sources each generate said constant amounts of current.
Claim 28
Dependent Claim
37 words
The amplifier circuit of claim 23 wherein said first bias circuit means includes: a zener diode connected to said base electrode of said master current control transistor; and a fourth current source connected to said zener diode.
Claim 29
Dependent Claim
231 words
The amplifier circuit of claim 23 further including: third electron control means having first, second and control electrodes which is rendered conductive between its first and second electrodes in response to a temperature variable threshold voltage between its first and control electrodes; eleventh circuit means coupling said first and second electrodes of said third electron control means respectively to said emitter and base electrodes of said master current control transistor; heat conductive means thermally connecting said third electron control means and said first and second transistor means which causes said third electron control means to have a temperature that is a function of the temperature of said first and second transistor means; second bias circuit means connected between and providing a constant bias voltage between said first and control electrodes of said third electron control means which has a magnitude that is less than the threshold voltage which corresponds to predetermined temperatures of said first and second transistor means, said threshold voltage of said third electron control means decreasing as the temperature of either the first or second transistor means increases, said third electron control means being rendered conductive by said threshold voltage becoming less than said constant bias voltage in response to the predetermined temperature thereby rendering said master current control transistor non-conductive before the temperature of either the first or second transistor means can exceed a maximum safe limit.
Claim 30
Dependent Claim
89 words
The amplifier of claim 25 wherein said third electron control means includes: first and second control transistors each having emitter, base and collector electrodes; said emitter, base and collector electrodes of said first control transistor being connected respectively to said emitter, base and collector electrodes of said second control transistor; said first control transistor being located in close proximity to said first transistor means to sense the temperature thereof; and said second control transistor being located in close proximity to said second transistor means to sense the temperature thereof.
References Cited (Backward Citations)
US3667064A
Cited
US3668541A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |