US3727148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier with protective energy limiter circuit components
Assignee: Carver Corp
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Filing: 1972-01-10
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Granted: 1973-04-10
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Expires: 1992-01-10
Abstract
Abstract A direct coupled state high fidelity amplifier incorporates an energy limiting circuit to provide protection against the user accidentally overloading and damaging the amplifier. The energy limiting circuit is designed so that the output transistors of the amplifier cannot be required to carry a specified amount of power for a longer period than would permit their safe operation without damage. This is done by examining and limiting the time integral of the product of voltage and current, i.e., energy, that the output transistors of the amplifier absorb. The result of using the energy limiting circuit is an increase in the efficiency of utilization of the output transistors, which in turn allows for an increase in power supplied by the amplifier to other components of the stereo system, while reducing the number of output transistors required.
Inventors
- 👤 R Carver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:50
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/211; H03F1/00; H03F1/52; H03G; H03G11/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
315 words
An energy limiting protection circuit for inclusion in a direct coupled, solid state, amplifier composed of the following: a transistor having connected to its base electrode four resistors and a capacitor in parallel with each other and each separately in series with the transistor; the bottom ends of the said capacitor and one of the said resistors connected in series to the top end of another resistor; the bottom end of another of the first said four resistors connected to another capacitor whose bottom end is connected to ground; the bottom end of the third of the first four said resistors connected to two additional resistors which are in parallel with each other; the bottom end of the first of the two additional said resistors connected to the top end of the resistor which also has the first said capacitor and one of the first four said resistors, connected to its top end, and its bottom end is connected to the amplifier output; the bottom end of the last of the first four said resistors and the bottom end of the second of the two additional said resistors are connected together to form a junction terminal which is also connected to the top end of a diode whose bottom end is connected to ground; a third capacitor not previously mentioned whose bottom end is connected to the amplifier output terminal and whose top end is connected to another junction terminal formed by the connection of the top end of the first of the two said additional parallel resistors, and to the bottom end of the adjacent resistor, which is one of the first said four resistors; the collector electrode of the said first transistor is connected to the cathode end of a diode, whose anode end connects to the amplifier drive; and the emitter electrode of the said first transistor connected to the amplifier output.
Claim 2
Dependent Claim
315 words
An energy limiting protection circuit for inclusion in a direct coupled, solid state, amplifier composed of the following: a transistor having connected to its base electrode four resistors and a capacitor in parallel with each other and each separately in series with the transistor; the bottom ends of the said capacitor and one of the said resistors connected in series to the top end of another resistor; the bottom end of another of the first said four resistors connected to another capacitor whose bottom end is connected to ground; the bottom end of the third of the first four said resistors connected to two additional resistors which are in parallel with each other; the bottom end of the first of the two additional said resistors connected to the top end of the resistor which also has the first said capacitor and one of the first four said resistors, connected to its top end, and its bottom end is connected to the amplifier output; the bottom end of the last of the first four said resistors and the bottom end of the second of the two additional said resistors are connected together to form a junction terminal which is also connected to the top end of a diode whose bottom end is connected to ground; a third capacitor not previously mentioned whose bottom end is connected to the amplifier output terminal and whose top end is connected to another junction terminal formed by the connection of the top end of the first of the two said additional parallel resistors, and to the bottom end of the adjacent resistor, which is one of the first said four resistors; the collector electrode of the said first transistor is connected to the cathode end of a diode, whose anode end connects to the amplifier drive; and the emitter electrode of the said first transistor connected to the amplifier output.
Claim 3
Dependent Claim
41 words
An energy limiting protection circuit, as claimed in claim 1, in which a transistor has between its base electrode and a remote resistor, a pair of series resistances with a capacitor at their junction connected together to perform an integrating function.
Claim 4
Dependent Claim
38 words
An energy limiting protection circuit, as claimed in claim 1, in which a resistor, sensitive to the output voltage swing, is connected to a capacitor in parallel, and is used to discharge the capacitor, thereby reSetting the integrator.
Claim 5
Dependent Claim
33 words
An energy limiting protection circuit as claimed in claim 1, in which a resistor and a capacitor, connected in series, are used to sense the time rate, dv/dt, of the voltage output swing.
Claim 6
Dependent Claim
246 words
In combination with an amplifier, an energy limiting protection circuit which develops an output voltage which is an analog representation of the instantaneous silicon chip temperature of amplifier transistors to be protected and when this analog output voltage reaches a predetermined threshold the energy limiting protection circuit diverts incoming driving current around the transistors needing protection, the energy limiting protection circuit, comprising: a. a resistor to receive current, I, and to develop a voltage at a wiring summing junction; b. a capacitor to create a derivative of the current, I, dI/dt and make it effective at the wiring summing junction; c. another resistor and another capacitor to generate a time integral of current I, Idt, and make it effective at the wiring summing junction; d. a third resistor to provide a voltage, V, at the wiring summing junction which is directly proportional to the voltage across output transistors of the amplifier; e. a fourth resistor and another capacitor to create a time derivative dv/dt of the output voltage at the wiring summing junction to limit any amplifier output at extreme dv/dt rates such as occurs during high frequency clipping; f. a limiter transistor to be turned on when an extreme condition is occurring; and g. a diode to receive current from this transistor and to conduct it to the base of a drive transistor of the amplifier to shunt the driving current away thereby preventing any further energy absorption by the output transistors of the amplifier.
Claim 7
Dependent Claim
246 words
In combination with an amplifier, an energy limiting protection circuit which develops an output voltage which is an analog representation of the instantaneous silicon chip temperature of amplifier transistors to be protected and when this analog output voltage reaches a predetermined threshold the energy limiting protection circuit diverts incoming driving current around the transistors needing protection, the energy limiting protection circuit, comprising: a. a resistor to receive current, I, and to develop a voltage at a wiring summing junction; b. a capacitor to create a derivative of the current, I, dI/dt and make it effective at the wiring summing junction; c. another resistor and another capacitor to generate a time integral of current I, Idt, and make it effective at the wiring summing junction; d. a third resistor to provide a voltage, V, at the wiring summing junction which is directly proportional to the voltage across output transistors of the amplifier; e. a fourth resistor and another capacitor to create a time derivative dv/dt of the output voltage at the wiring summing junction to limit any amplifier output at extreme dv/dt rates such as occurs during high frequency clipping; f. a limiter transistor to be turned on when an extreme condition is occurring; and g. a diode to receive current from this transistor and to conduct it to the base of a drive transistor of the amplifier to shunt the driving current away thereby preventing any further energy absorption by the output transistors of the amplifier.
References Cited (Backward Citations)
US3564338A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |