Patent US4301330A successfully refreshed from Google Patents.
US4301330A
Expired / Lapsed
US
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Loudspeaker protection circuit
Assignee: PB Electronics Inc
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Filing: 1979-09-28
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Granted: 1981-11-17
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Expires: 1999-09-28
Abstract
Abstract A loudspeaker protection circuit senses an overload condition caused by an improper input signal or a fault within the amplifier by sensing a DC or infrasonic signal applied to the loudspeaker. The time between zero (axis) crossings of the amplifier output signal, which are related to the lower frequency components of the signal, are detected. If the period of time between zero crossings exceeds a predetermined time limit, the supply of the amplifier output signal to the loudspeaker is interrupted. In order to prevent false tripping of the circuit by normal conditions, the circuit only responds to signals exceeding a predetermined voltage level.
Inventors
- 👤 Bruce Trump
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:06
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/007
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
92 words
A protection circuit for a loudspeaker driven by an amplifier comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between selected control signals exceeds a predetermined limit; and switch means in circuit between said amplifier and said loudspeaker and coupled to said interval timing means for receiving said disconnect signal for interrupting the supply of said driving signal to said loudspeaker.
Claim 2
Dependent Claim
92 words
A protection circuit for a loudspeaker driven by an amplifier comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between selected control signals exceeds a predetermined limit; and switch means in circuit between said amplifier and said loudspeaker and coupled to said interval timing means for receiving said disconnect signal for interrupting the supply of said driving signal to said loudspeaker.
Claim 3
Dependent Claim
16 words
The circuit of claim 1 wherein said switch means disconnects said loudspeaker from the amplifier output.
Claim 4
Dependent Claim
22 words
The protection circuit of claim 1 or 2 wherein said threshold voltage is a voltage level of either positive or negative polarity.
Claim 5
Dependent Claim
13 words
The protection circuit of claim 1 wherein said predetermined limit is 50 milliseconds.
Claim 6
Dependent Claim
13 words
The protection circuit of claim 3 wherein said selected control signals are consecutive.
Claim 7
Dependent Claim
57 words
The protection circuit of claim 5 wherein said switch means restores the supply of said driving signal to said loudspeaker when said disconnect signal is no longer present; said circuit further including delay timer means for inhibiting said restoration of said driving signal for a predetermined period of time after said disconnect signal is no longer present.
Claim 8
Dependent Claim
144 words
A protection circuit for a loudspeaker driven by an amplifier comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage of either positive or negative polarity; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between consecutive control signals exceeds a predetermined limit; delay timer means coupled to said interval timing means for receiving said disconnect signal and delaying said disconnect signal a predetermined time interval; and switch means in circuit between said amplifier and said loudspeaker and coupled to said delay timer means for receiving said delayed disconnect signal for interrupting the supply of said driving signals to said loudspeaker with said driving signals being restored to said loudspeaker following said predetermined time interval after said disconnect signal is no longer present.
Claim 9
Dependent Claim
144 words
A protection circuit for a loudspeaker driven by an amplifier comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage of either positive or negative polarity; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between consecutive control signals exceeds a predetermined limit; delay timer means coupled to said interval timing means for receiving said disconnect signal and delaying said disconnect signal a predetermined time interval; and switch means in circuit between said amplifier and said loudspeaker and coupled to said delay timer means for receiving said delayed disconnect signal for interrupting the supply of said driving signals to said loudspeaker with said driving signals being restored to said loudspeaker following said predetermined time interval after said disconnect signal is no longer present.
Claim 10
Dependent Claim
98 words
A protection circuit for a loudspeaker driven by an amplifier energized by a power supply comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between selected control signals exceeds a predetermined limit; and switch means connected between said amplifier and said power supply and coupled to said interval timing means for receiving said disconnect signal for interrupting the power provided to said amplifier thereby de-energizing said loudspeaker.
Claim 11
Dependent Claim
98 words
A protection circuit for a loudspeaker driven by an amplifier energized by a power supply comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between selected control signals exceeds a predetermined limit; and switch means connected between said amplifier and said power supply and coupled to said interval timing means for receiving said disconnect signal for interrupting the power provided to said amplifier thereby de-energizing said loudspeaker.
Claim 12
Dependent Claim
20 words
The protection circuit of claim 8 wherein said threshold voltage is a voltage level of either positive or negative polarity.
Claim 13
Dependent Claim
13 words
The protection circuit of claim 8 wherein said predetermined limit is 50 milliseconds.
Claim 14
Dependent Claim
13 words
The protection circuit of claim 8 wherein said selected control signals are consecutive.
Claim 15
Dependent Claim
57 words
The protection circuit of claim 8 wherein said switch means restores the supply of said power signal to said amplifier when said disconnect signal is no longer present, said circuit further including delay timer means for inhibiting said restoration of said power signal for a predetermined period of time after said disconnect signal is no longer present.
Claim 16
Dependent Claim
148 words
A protection circuit for a loudspeaker driven by an amplifier energized by a power supply comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage of either positive or negative polarity; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between consecutive control signals exceeds a predetermined limit; delay timer means coupled to said interval timing means for receiving said disconnect signal and delaying said disconnect signal a predetermined time interval; and switch means connected between said amplifier and said power supply and coupled to said delay timer means for receiving said delayed disconnect signals for interrupting the power provided to said amplifier thereby de-energizing said loudspeaker with power being restored to said amplifier following said predetermined time interval after said disconnect signal is no longer present.
Claim 17
Dependent Claim
148 words
A protection circuit for a loudspeaker driven by an amplifier energized by a power supply comprising: detector means coupled to said amplifier for generating a control signal when a signal driving said loudspeaker crosses a predetermined threshold voltage of either positive or negative polarity; interval timing means coupled to said detector means for generating a disconnect signal when the time interval between consecutive control signals exceeds a predetermined limit; delay timer means coupled to said interval timing means for receiving said disconnect signal and delaying said disconnect signal a predetermined time interval; and switch means connected between said amplifier and said power supply and coupled to said delay timer means for receiving said delayed disconnect signals for interrupting the power provided to said amplifier thereby de-energizing said loudspeaker with power being restored to said amplifier following said predetermined time interval after said disconnect signal is no longer present.
References Cited (Backward Citations)
US3882545A
Cited
US3828258A
Cited
US3835336A
Cited
US3965295A
Cited
US3988694A
Cited
US3959735A
Cited
US4034268A
Cited
US4122400A
Cited
US4127743A
Cited
US4122507A
Cited
US4173740A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-16 | 1985-05-18 | 1985-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-16 | 1989-05-18 | 1989-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-16 | 1993-05-18 | 1993-11-17 | $7700.00 | Window Closed / Lapsed |