Piezoelectric Loudspeaker Voltage Control for Sound Quality
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Solution Overview
Problem
Existing piezoelectric loudspeaker technologies produce sound waves with insufficient quality due to inefficient charging and discharging mechanisms, leading to suboptimal deflection control of the piezo actuator, which affects the precision and quality of generated sound waves.
Innovation Solution
A method and circuit for operating a piezoelectric loudspeaker that involves predicting and controlling the differential voltage across the piezo actuator by comparing future input voltage with current voltage, allowing for precise charging and discharging to optimize deflection, thereby enhancing sound quality. This includes using a recharging unit like an inductor to store differential energy and determining charging and discharging times based on audio signal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional charging and discharging mechanisms are used for the piezo actuator, then the device complexity is reduced, but the sound quality and deflection control precision deteriorate
Solution Approach 1:
The patent applies preliminary action by predicting the future input voltage before it actually occurs. The prediction unit forecasts the voltage that will be required in the next time step, allowing the system to prepare the appropriate charge or discharge operation in advance. This predictive approach enables more precise deflection control by ensuring the piezo actuator receives the correct voltage timing, thereby improving sound quality without requiring overly complex real-time control mechanisms.
2Manufacturing precision
If the piezo actuator is continuously charged to increase deflection, then the sound wave generation capability is improved, but the energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the charging and discharging operations adaptive rather than static. The control unit dynamically adjusts whether to charge or discharge the piezo actuator based on the comparison between current voltage and predicted future voltage. This dynamic approach allows the system to consume energy only when necessary to achieve the desired deflection changes, optimizing the balance between sound wave generation quality and energy consumption.
Solution Approach 2:
The patent applies discarding and recovering by utilizing the discharge operation to recover energy back to the energy storage unit. Instead of continuously consuming energy from the energy storage unit, the system recovers energy during discharge phases when the piezo actuator needs to reduce its voltage. This energy recovery mechanism reduces overall energy consumption while maintaining the ability to generate high-quality sound waves when needed.
3Manufacturing precision
If the charging and discharging times are extended to improve deflection control, then the manufacturing precision is improved, but the response time and productivity are reduced
Solution Approach 1:
The patent applies preliminary action by predicting future voltage requirements in advance, which allows the control unit to optimize charging and discharging timing. By knowing what voltage will be needed next, the system can perform charge/discharge operations more efficiently with shorter durations, improving both precision and response time simultaneously rather than requiring extended operation times.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the charging and discharging time durations based on the specific voltage transition requirements. Rather than using fixed, extended charging/discharging times, the system adapts the duration parameters to match the actual needs of each voltage transition, achieving precise deflection control with minimized response time and optimized productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method and circuit improve the quality of sound waves by precisely controlling the deflection of the piezo actuator, resulting in higher fidelity for audible and ultrasonic sound generation, with the ability to generate sound waves with frequencies up to 1 MHz, which is beyond the human hearing range.
Implementation Method 1
a piezo actuator of the piezoelectric loudspeaker is at least partially charged with electrical energy from an energy unit and at least partially discharged again, as a result of which sound waves are generated
Data Source
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AI summary
The invention relates to a method for operating a piezoelectric loudspeaker (2) for generating sound waves in the audible wavelength spectrum and/or in the ultrasound range, in which a piezoelectric actuator (24) of the piezoelectric loudspeaker (2) is at least partially charged and at least partially discharged with electrical energy from an energy unit (3), thereby generating sound waves, and in which at least one current electrical piezoelectric actuator voltage (12, 13) of the piezoelectric actuator (24) is determined. According to the invention, before charging and/or discharging, a future input voltage (14) for the piezoelectric actuator (24) is compared with the current electrical piezoelectric actuator voltage (12, 13), and a future differential voltage (15) is determined therefrom. Furthermore, a portion of the energy stored in the piezoelectric actuator (24) can be recharged into the energy unit (3) during discharge.