DEVICE WITH PRECISION FREQUENCY STABILIZED AUDIBLE ALARM CIRCUIT
First Claim
Patent Images
1. A device, comprising:
- a three terminal piezo-electric buzzer;
driver circuitry coupled to the piezo-electric buzzer and operative to drive operation of the piezo-electric buzzer, wherein the operation of the piezo-electric buzzer is characterized by a resonant frequency and buzzer phase; and
compensation circuitry coupled to the piezo-electric buzzer and the driver circuitry to complete a circuit loop comprising the driver circuitry, the piezo-electric buzzer, and the compensation circuitry, the compensation circuitry operative to assist the driver circuitry in maintaining the piezo-electric buzzer in a stable oscillation by injecting additional phase into the circuit loop to supplement the buzzer phase and to enable the piezo-electric buzzer to operate at, or near, the resonant frequency.
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Abstract
Systems for ensuring an audible alarm circuit sounds at a minimum magnitude of loudness are provided. Different circuitry embodiments discussed herein are each capable of assisting the audible alarm circuit in maintaining a minimum loudness threshold. Audible alarm circuit operation optimization can be achieved using embodiments that fall within anyone of four general categories: compensation networks, direct drive, dynamic tuning, and microphone feedback based dynamic tuning. Use of such circuitry can increase production yields by compensating for manufacturing variations of alarm components and aging characteristics of the components.
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Citations
23 Claims
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1. A device, comprising:
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a three terminal piezo-electric buzzer; driver circuitry coupled to the piezo-electric buzzer and operative to drive operation of the piezo-electric buzzer, wherein the operation of the piezo-electric buzzer is characterized by a resonant frequency and buzzer phase; and compensation circuitry coupled to the piezo-electric buzzer and the driver circuitry to complete a circuit loop comprising the driver circuitry, the piezo-electric buzzer, and the compensation circuitry, the compensation circuitry operative to assist the driver circuitry in maintaining the piezo-electric buzzer in a stable oscillation by injecting additional phase into the circuit loop to supplement the buzzer phase and to enable the piezo-electric buzzer to operate at, or near, the resonant frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A device comprising:
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a piezo-electric buzzer characterized as having a resonant frequency existing between first and second frequencies; driver circuitry coupled to the piezo-electric buzzer, the driver circuitry operative to provide a power signal to the piezo-electric buzzer; and a control unit coupled to the driver circuitry and operative to cause the driver circuitry to provide a frequency modulated power signal to the piezo-electric buzzer, wherein the frequency modulated power signal sweeps between the first and second frequencies such that when the modulated power signal is near the resonant frequency, the piezo-electric buzzer emits an audio output. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A maximum resonance driving device comprising:
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an electroacoustic transducer; driver circuitry coupled to the transducer, the driver circuitry operative to drive operation of the transducer; control circuitry coupled to the driver circuitry, the control circuitry operative to provide a signal that can vary output of the driver circuitry; and sense circuitry coupled to an output of the driver circuitry and to the control circuitry, the sense circuitry operative to; monitor the output of the driver circuitry; and instruct the control circuitry to change a value of the signal based on the monitored output such that the transducer emits an audio signal having at least a minimum magnitude. - View Dependent Claims (17, 18, 19)
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20. A device comprising:
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an electroacoustic transducer; driver circuitry coupled to the transducer, the driver circuitry operative to drive operation of the transducer; control circuitry coupled to the driver circuitry, the control circuitry operative to provide a signal that can vary output of the driver circuitry; a microphone; sense circuitry coupled to the control circuitry and the microphone, the sense circuitry operative to; monitor an output of the microphone; and instruct the control circuitry to change a value of its adjustable network based on the monitored output of the microphone such that the transducer emits an audio signal having at least a minimum magnitude. - View Dependent Claims (21, 22, 23)
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Specification