Loudspeaker protection circuit
AssigneeZenith Radio Corporation
InventorBruce Trump
Life of this patent
Estimating the term…
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.
Claims13
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.
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.
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.
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.
Dependencies are inferred from the claim text.