Ultrasonic Sensor Damping Circuit for Reverberation Reduction
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Solution Overview
Problem
Ultrasonic sensors with piezoelectric elements face challenges in effectively reducing reverberation time, which affects their ability to detect objects in close range due to prolonged mechanical energy accumulation, leading to increased reverberation times.
Innovation Solution
The ultrasonic sensor employs a semiconductor device with a drive circuit that supplies a damping signal with a phase different from the drive signal after transmission, and a damping circuit with variable resistive and inductive loads to rapidly reduce reverberation by controlling the connection and disconnection of these loads to the piezoelectric element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the piezoelectric element is driven to transmit ultrasonic waves, then distance detection capability is achieved, but reverberation time increases due to prolonged mechanical energy accumulation
Solution Approach 1:
The patent applies preliminary anti-action by introducing a damping signal with opposite phase to the drive signal before the natural reverberation can interfere with detection. The damping circuit generates this counteracting signal to preemptively reduce mechanical energy accumulation in the piezoelectric element, thereby shortening reverberation time and improving close-range detection capability
2Duration of action of stationary object
If a damping circuit with variable loads is used to reduce reverberation, then reverberation time decreases, but device complexity increases
Solution Approach 1:
The patent implements dynamics by using variable resistive and inductive loads that can be adjusted based on operating conditions. The damping circuit dynamically changes its impedance characteristics to optimize reverberation reduction efficiency, allowing the system to adapt to different detection scenarios and maintain effectiveness across varying conditions
Solution Approach 2:
The damping circuit is designed to serve multiple functions: it provides reverberation reduction, enables close-range detection, and can operate in different modes (resistive damping, inductive damping, or combined) depending on the situation. This multi-functionality justifies the added complexity by delivering versatile performance improvements
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
This approach effectively reduces reverberation time, enhancing the sensor's ability to detect objects in close proximity by efficiently dissipating mechanical energy, thereby improving detection accuracy and speed.
Implementation Method 1
Ultrasonic sensors which include piezoelectric elements are used in various applications. The ultrasonic sensor drives the piezoelectric element to transmit a transmission wave signal, and receives a reflected wave signal
Implementation Method 2
a damping circuit with variable resistive and inductive loads to rapidly reduce reverberation by controlling the connection and disconnection of these loads to the piezoelectric element
Data Source
AI summary
In a semiconductor device, a drive circuit is used to supply a drive signal in an ultrasonic band to a piezoelectric element, and thereafter through a brake operation, a damping signal having a phase different from the phase of the drive signal is supplied to the piezoelectric element. The drive circuit includes a full bridge circuit provided between a first line and a second line. In the brake operation, two switches on the side of the first line in the full bridge circuit are turned on or two switches on the side of the second line in the full bridge circuit are turned on.