US4229706A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio amplifier
Assignee: Individual
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Filing: 1979-01-05
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Granted: 1980-10-21
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Expires: 1999-01-05
Abstract
Abstract Disclosed is a Class A power amplifier circuit which includes means for controlling the quiescent bias current of the output devices of the amplifier and providing absolute overload and short circuit protection without the need of extra protective devices of any kind. The circuit includes a driver stage which amplifies an input signal and provides two outputs which are out of phase with respect to each other by 180°. One output of the driver stage provides a drive signal to the control input of a first output device, while the other output of the driver stage provides a drive signal to the control input of a second output device. Power is provided to the driver stage by a standard grounded center-tapped power supply. A pair of independent floating power supplies are cross-connected between the two output devices so that the supply terminal of each output device is connected to one terminal of one of the power supplies, while the output terminal of each of the output devices is connected to the opposite phase terminal of the opposite power supply. A resistor is connected between the output terminal of each of the output devices and one terminal of the power supply which powers the driver stages. The load is connected between output terminals of the output devices. The circuit arrangement provides control of the value of the quiescent control input current of each of the output devices which in turn controls the quiescent value of the bias currents of each of the output devices, thus resulting in an amplifier of greatly improved thermal stability.
Inventors
- 👤 James W. Bongiorno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:09
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
138 words
A solid-state amplifier, comprising: driver means for amplifying an input signal, said driver means having two outputs; first and second solid-state output devices having a control input terminal, a supply terminal and an output terminal, wherein the control input terminal of the first output device is connected to one output of said driver means and the control input terminal of the second output device is connected to the other output of said driver means; driver power supply means for powering said driver means; first floating independent supply means for powering said first output device; second floating independent supply means for powering said second output device; and passive control means for maintaining the quiescent value of the control input current to said first and second output devices at a constant, predetermined level despite temperature variations in the output devices.
Claim 2
Dependent Claim
138 words
A solid-state amplifier, comprising: driver means for amplifying an input signal, said driver means having two outputs; first and second solid-state output devices having a control input terminal, a supply terminal and an output terminal, wherein the control input terminal of the first output device is connected to one output of said driver means and the control input terminal of the second output device is connected to the other output of said driver means; driver power supply means for powering said driver means; first floating independent supply means for powering said first output device; second floating independent supply means for powering said second output device; and passive control means for maintaining the quiescent value of the control input current to said first and second output devices at a constant, predetermined level despite temperature variations in the output devices.
Claim 3
Dependent Claim
51 words
The amplifier of claim 1 wherein said control means includes a first control resistor connected between the output terminal of said first output device and said driver power supply means, and a second control resistor connected between the output terminal of said second output device and said driver power supply means.
Claim 4
Dependent Claim
234 words
A solid-state amplifier comprising: a driver means for providing two drive signals of opposite phase; first and second solid-state output devices, each of said output devices having a control input terminal, a supply terminal and an output terminal, wherein the control terminal of the first output device is connected to one output of said driver means and the control terminal of the second output device is connected to the other output of said driver means; driver power supply means for providing operating voltages to said driver means; a first control resistor connected between the output terminal of said first output device and a terminal of said driver power supply means; a second control resistor connected between the output terminal of said first output device and a terminal of said driver power supply means; a first floating independent power supply, the positive terminal of which is connected to the supply terminal of said first output device and the negative terminal of which is connected to the output terminal of said second outout device; and a second floating independent power supply, the positive terminal of which is connected to the supply terminal of said second output device and the negative terminal of which is connected to the output terminal of said first output device, said amplifier being utilized to drive a load which is connected between the output terminals of said first and second output devices.
Claim 5
Dependent Claim
234 words
A solid-state amplifier comprising: a driver means for providing two drive signals of opposite phase; first and second solid-state output devices, each of said output devices having a control input terminal, a supply terminal and an output terminal, wherein the control terminal of the first output device is connected to one output of said driver means and the control terminal of the second output device is connected to the other output of said driver means; driver power supply means for providing operating voltages to said driver means; a first control resistor connected between the output terminal of said first output device and a terminal of said driver power supply means; a second control resistor connected between the output terminal of said first output device and a terminal of said driver power supply means; a first floating independent power supply, the positive terminal of which is connected to the supply terminal of said first output device and the negative terminal of which is connected to the output terminal of said second outout device; and a second floating independent power supply, the positive terminal of which is connected to the supply terminal of said second output device and the negative terminal of which is connected to the output terminal of said first output device, said amplifier being utilized to drive a load which is connected between the output terminals of said first and second output devices.
Claim 6
Dependent Claim
13 words
The amplifier of claim 1 wherein said amplifier is a Class A amplifier.
Claim 7
Dependent Claim
29 words
The amplifier of claim 1 further including negative feedback means connected between the input of said driver means and the output terminals of said first and second output devices.
Claim 8
Dependent Claim
59 words
The amplifier of claim 1 wherein each of said output devices comprises a single transistor, the base of which is connected to the control input terminal of the output device, the collector of which is connected to the supply terminal of the output device, and the emitter of which is connected to the output terminal of the output device.
Claim 9
Dependent Claim
21 words
The amplifier of claim 1 wherein each of said output devices comprises a plurality of transistors connected in a parallel fashion.
Claim 10
Dependent Claim
21 words
The amplifier of claim 1 wherein each of said output devices comprises a plurality of transistors connected in a compound configuration.
Claim 11
Dependent Claim
84 words
The amplifier of claim 1 further including: a first resistor having one lead connected to the output terminal of said first output device, and a diode whose anode is connected to the other lead of said first resistor, and whose cathode is connected to ground; and a second resistor having one lead connected to the output terminal of said second output device, and a diode whose anode is connected to the other lead of said second resistor and whose cathode is connected to ground.
Claim 12
Dependent Claim
179 words
A bridge connected output stage for an amplifier comprising: a first output device having a control input, a supply input and an output; a first floating independent power supply, the first terminal of which is connected to the supply input of said first output device, said first output device and said first power supply forming one side of a bridge; a second output device having a control input, a supply input and an output, said output being connected to the second terminal of said first power supply; a second floating independent power supply, one terminal of which is connected to the supply input of said second output device and the other terminal of which is connected to the output terminal of said first output device, said second output device and said second power supply forming the other side of the bridge; a third power supply; and passive means, connected to the third power supply, for maintaining the quiescent value of the control input current to said output devices at a constant level despite temperature variations in the output devices.
Claim 13
Dependent Claim
179 words
A bridge connected output stage for an amplifier comprising: a first output device having a control input, a supply input and an output; a first floating independent power supply, the first terminal of which is connected to the supply input of said first output device, said first output device and said first power supply forming one side of a bridge; a second output device having a control input, a supply input and an output, said output being connected to the second terminal of said first power supply; a second floating independent power supply, one terminal of which is connected to the supply input of said second output device and the other terminal of which is connected to the output terminal of said first output device, said second output device and said second power supply forming the other side of the bridge; a third power supply; and passive means, connected to the third power supply, for maintaining the quiescent value of the control input current to said output devices at a constant level despite temperature variations in the output devices.
Claim 14
Dependent Claim
175 words
A linear audio amplifier comprising: a bridge having a first floating power supply connected with one polarity in series with a first transistor amplifying device across two opposite nodes of said bridge, and a second floating power supply connected with opposite polarity in series with a second transistor amplifying device across the same two nodes, a load being connectable across said same nodes; independent first and second high impedance current source bias circuits respectively connected to said first and second transistor amplifying devices, each of said bias circuits including a passive current control element and providing a current which is entirely constrained to the base-to-emitter path of the associated transistor amplifying device whereby no bias current flows through either floating power supply, the current provided by each current source being determined by said passive element so that said bias circuit maintains the base current of that associated transistor device constant regardless of temperature change; and drive means for supplying corresponding but oppositely phased audio signals to the inputs of said first and second transistor devices.
Claim 15
Dependent Claim
175 words
A linear audio amplifier comprising: a bridge having a first floating power supply connected with one polarity in series with a first transistor amplifying device across two opposite nodes of said bridge, and a second floating power supply connected with opposite polarity in series with a second transistor amplifying device across the same two nodes, a load being connectable across said same nodes; independent first and second high impedance current source bias circuits respectively connected to said first and second transistor amplifying devices, each of said bias circuits including a passive current control element and providing a current which is entirely constrained to the base-to-emitter path of the associated transistor amplifying device whereby no bias current flows through either floating power supply, the current provided by each current source being determined by said passive element so that said bias circuit maintains the base current of that associated transistor device constant regardless of temperature change; and drive means for supplying corresponding but oppositely phased audio signals to the inputs of said first and second transistor devices.
Claim 16
Dependent Claim
40 words
A linear audio amplifier according to claim 11 wherein said bias circuits provide currents having values such that each transistor amplifying device is biased to operate in the linear range thereof, said amplifier thus operating in the Class A mode.
Claim 17
Dependent Claim
79 words
A linear amplifier according to claim 11 wherein each of said transistor amplifying devices comprises at least one transistor, each transistor being poled for forward current flow from the corresponding floating power supply through the collector-to-emitter path of that transistor, and wherein the impedance of said current source is established by a resistor in said bias circuit through which said bias current flows, the resistance of said resistors being substantially greater than the base-to-emitter impedance of the corresponding transistor.
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) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |