Variable-Current Ultrasound TIA for Low-Noise Signal Acquisition
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Solution Overview
Problem
Ultrasound amplifiers face challenges in maintaining linear signal amplification and reducing noise while minimizing power consumption, especially during ultrasound signal acquisition, where noise levels and signal amplitudes vary with depth.
Innovation Solution
The use of a two-stage transimpedance amplifier (TIA) with variable current sources and a variable feedback impedance, allowing for dynamic control of noise and linearity through programmable current settings and digital controllers, adjusts power consumption and noise levels to maintain signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amplifier uses high current to maintain low noise levels and linear amplification, then signal quality is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic current adjustment by switching between first and second current sources based on signal acquisition timing. The current through the transimpedance amplifier is varied over time - using higher current during critical acquisition periods to maintain low noise, and reducing current during other periods to save power, thus resolving the contradiction between signal quality and power consumption
Solution Approach 2:
The amplifier operates in periodic cycles alternating between signal acquisition mode (with higher current for low noise) and power-saving mode (with lower current). This periodic switching of current levels allows the system to achieve low noise when needed while minimizing overall power consumption through timed current reduction
2Reliability
If the amplifier uses high current to maintain linear amplification, then amplification quality is improved, but power consumption increases
Solution Approach 1:
The patent dynamically adjusts the current level through the transimpedance amplifier by switching between different current sources. During signal acquisition when linear amplification is critical, higher current is supplied to maintain amplification quality. During non-acquisition periods, current is reduced to minimize power consumption, thus resolving the contradiction between amplification quality and power consumption
3Reliability
If the amplifier reduces noise levels during signal acquisition, then signal quality is improved, but power consumption increases
Solution Approach 1:
The amplifier employs periodic current adjustment where high current is supplied only during the specific time window when ultrasound signals are acquired and low noise is critical. Outside this window, current is reduced to save power. This time-based periodic action resolves the contradiction by applying high power only when it provides benefit to signal quality
4Adaptability or versatility
If the amplifier uses variable current sources and feedback impedance, then adaptability is improved, but device complexity increases
Solution Approach 1:
The amplifier is segmented into distinct functional modules: first and second current sources, transimpedance amplifier stage, operational amplifier, and feedback impedance network. Each module can be independently controlled and optimized. This segmentation allows the system to achieve high adaptability through coordinated control of multiple simpler components rather than requiring a single complex adjustable device
Solution Approach 2:
The feedback impedance network serves multiple functions: it sets the transimpedance gain, controls noise characteristics, and influences linearity of amplification. By making the feedback impedance variable, a single component performs multiple optimization functions, improving adaptability without proportionally increasing overall device complexity
Data Source
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AI summary
A variable current trans-impedance amplifier (TIA) for an ultrasound device is described. The TIA may be coupled to an ultrasonic transducer to amplify an output signal of the ultrasonic transducer representing an ultrasound signal received by the ultrasonic transducer. During acquisition of the ultrasound signal by the ultrasonic transducer, one or more current sources in the TIA may be varied.