Floating-Point ADC With Variable Reference for Wide Dynamic Range
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Solution Overview
Problem
Conventional analog-to-digital converters (ADCs) face challenges in handling wide dynamic range signals, particularly in terms of power consumption and complexity when increasing the number of bits, and struggle to maintain a high signal-to-noise ratio due to varying input signal amplitudes.
Innovation Solution
Implementing a floating-point ADC with a variable reference voltage, where one signal processing circuit provides a fixed reference voltage and others use a variable voltage derived from the strongest signal, allowing for a dynamic range extension with reduced power dissipation and circuit complexity, using a successive-approximation method with digital mantissa and exponent outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of bits in the ADC output is increased to handle wide dynamic range signals, then the dynamic range capability is improved, but the power consumption and circuit complexity increase
Solution Approach 1:
The patent divides the ADC output into two separate digital outputs: a mantissa portion and an exponent portion. This segmentation allows the system to represent wide dynamic range values efficiently without requiring a single high-bit ADC, thereby reducing circuit complexity while maintaining extended dynamic range capability.
Solution Approach 2:
The patent transitions from a single-dimensional bit-depth approach to a two-dimensional representation using mantissa and exponent components. This dimensional change enables efficient representation of wide dynamic range signals without proportionally increasing the complexity of the ADC circuitry.
2Adaptability or versatility
If the number of bits in the ADC output is increased to handle wide dynamic range signals, then the dynamic range capability is improved, but the power consumption increases
Solution Approach 1:
By segmenting the ADC functionality into mantissa and exponent processing paths, the patent reduces the bit-depth requirement for the main ADC circuitry. This segmentation lowers power consumption while still achieving wide dynamic range representation through the combined mantissa-exponent output.
3Ease of operation
If an automatic-gain-control amplifier is used to keep the input below full-scale limit, then the signal amplitude control is improved, but the loop speed becomes dependent on conversion time and cannot track high bandwidth signals
Solution Approach 1:
The patent implements a variable reference voltage that dynamically adjusts based on the input signal characteristics. This dynamic reference voltage allows the ADC to adapt to varying signal amplitudes without requiring a slow feedback loop, thereby maintaining high bandwidth tracking capability while achieving proper signal level control.
Solution Approach 2:
The system performs preliminary action by pre-adjusting the reference voltage based on expected or detected signal characteristics before the main conversion process. This preliminary adjustment enables the ADC to handle wide dynamic range signals without requiring a slow corrective feedback loop, thus maintaining high loop speed.
4Adaptability or versatility
If a wide range ADC with many bits is used, then the dynamic range is improved, but the power consumption and complexity increase
Solution Approach 1:
The patent segments the dynamic range representation into mantissa and exponent components, allowing the use of a lower-bit ADC that consumes less power while still achieving wide overall dynamic range through the combined representation.
Solution Approach 2:
The patent changes the representation parameters from a single high-bit value to a pair of lower-bit values (mantissa and exponent). This parameter change achieves equivalent or superior dynamic range with reduced power consumption by avoiding the need for a high-bit ADC.
Data Source
AI summary
A system includes an analog-to-digital converter receiving input signals. One particular input signal has a particular analog value, and the analog-to-digital converter uses a fixed reference to convert the particular analog value to a particular digital value. The analog-to-digital converter uses the particular analog value as a reference for converting the analog values of the remaining input signals.