Ultrasonic Transducer Full-Bridge Control With Two-Pin Echo Sensing
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Solution Overview
Problem
Ultrasonic measuring systems for vehicles face challenges with high manufacturing costs due to the use of transformers or voltage converters, which increase the number of connection pins and pads in IC chips, and require separate ultrasonic transmitters and receivers, leading to increased space and cost.
Innovation Solution
An integrated circuit with two external terminals for an ultrasonic transducer, utilizing a full-bridge circuit and FET transistors to alternately apply high and low voltages, decoupling control and evaluation sections, and incorporating damping circuits to minimize connection pads and protect against ESD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transformer or voltage converter is used to generate high drive voltage, then the ultrasonic transducer can emit sufficient energy for distant object detection, but the manufacturing cost increases and the number of connection pins increases
Solution Approach 1:
The patent combines the high-voltage drive signal generation and low-voltage echo evaluation functions into a single integrated circuit chip. The full-bridge circuit with four semiconductor switches generates high drive voltage internally, eliminating the need for external transformers or voltage converters. This merging reduces the number of connection pins from multiple (required for separate high-voltage and low-voltage connections) to just two connection pins for the ultrasonic transducer.
Solution Approach 2:
The integrated circuit performs multiple functions: it generates high-voltage drive signals for the ultrasonic transducer during transmission, and simultaneously evaluates low-voltage echo signals during reception. The same two connection pins are used for both driving the transducer and receiving echo signals, demonstrating multi-functionality that reduces overall system complexity.
2Reliability
If separate ultrasonic transmitter and receiver components are used, then the system can reliably detect echo signals, but the space requirements and production costs increase
Solution Approach 1:
The patent merges the ultrasonic transmitter and receiver functions into a single integrated circuit chip. The control unit with full-bridge circuit handles transmission, while the evaluation unit handles reception, all on one chip. This consolidation significantly reduces the space required compared to separate discrete components while maintaining reliable echo detection through proper timing and signal processing.
Solution Approach 2:
The integrated circuit operates in periodic transmission and reception intervals. During transmission intervals, the full-bridge circuit drives the ultrasonic transducer; during reception intervals, the evaluation unit processes echo signals. This time-division multiplexing allows a single integrated circuit to perform both transmitter and receiver functions reliably.
3Ease of operation
If multiple connection pins are provided on the IC chip for separate drive and evaluation connections, then the system can function properly, but the chip area and manufacturing cost increase
Solution Approach 1:
The patent merges the drive signal output and echo signal input functions into a single integrated circuit with only two connection pins. The full-bridge circuit generates high-voltage drive signals internally, and the evaluation unit processes low-voltage echo signals internally, eliminating the need for separate external connection pins for high-voltage and low-voltage signals. This reduces chip area and simplifies manufacturing while maintaining proper functionality through internal signal routing and voltage level management.
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
Reduces the number of connection pads to two, lowers production costs, and provides effective protection against ESD, while maintaining reliable ultrasonic measurement capabilities.
Implementation Method 1
a voltage limiting element formed as part of the integrated circuit in the form of a FET transistor configured as a source follower in each electrical connection between the input terminals of the amplifier and the two IC terminals of the integrated circuit, wherein both voltage limiting elements limit the voltage applied to the input terminals of the amplifier to a value in the low-voltage range
Implementation Method 2
an alternately reversible drive voltage is applied to the IC terminals of the integrated circuit for the emission of an ultrasonic burst signal in a drive phase, and an evaluation voltage output by the ultrasonic transducer is applied to the IC terminals of the integrated circuit when receiving an ultrasonic echo signal in a receive phase
Data Source
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AI summary
The ultrasonic measuring device is equipped with a voltage converter-free ultrasonic transducer (10) having two terminals (18) to which an alternatingly reversible drive voltage can be applied for the emission of an ultrasonic burst signal in a drive phase, and to which an evaluation voltage is applied during the reception phase when an ultrasonic echo signal is received, wherein the ultrasonic transducer (10) oscillates in a decay phase between a drive phase and a reception phase. The ultrasonic measuring device further comprises a drive unit (23) for generating the drive voltage, wherein the drive unit (23) has a full bridge circuit (24) with two half-bridge circuits (26), each having two drive semiconductor switches (28), which are connected to the two terminals (18) of the ultrasonic transducer (10).Furthermore, an evaluation unit (49) is provided with an amplifier (50) that processes evaluation voltages in the low-voltage range and has two input terminals (52, 54), each connected via a connecting line (46, 48) to the terminals (18) of the ultrasonic transducer (10). Voltage limiting elements (56) in the two connecting lines (46, 48) limit the voltage applied to the input terminals (52, 54) of the amplifier (50) to a value in the low-voltage range. To evaluate an evaluation voltage applied to the terminals (18) of the ultrasonic transducer (10), the four control semiconductor switches (28) are switched off.