Regenerative Programmable-Gain Amplifier for Wide Gain and Bandwidth
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Solution Overview
Problem
Existing programmable-gain amplifiers face challenges in achieving wide range gain variation, constant bandwidth, low power consumption, and dB-linear gain control, with existing solutions often resulting in limited bandwidth, high power consumption, or complex implementations.
Innovation Solution
A programmable-gain amplifier utilizing a regenerative amplifier with two cross-coupled pairs and a preamplifier stage, implementing negative resistance and a digital-to-analog converter to control regeneration time for dB-linear gain control, achieving high gain and wide bandwidth with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional programmable-gain amplifier designs are used to achieve wide gain variation, then gain range is improved, but bandwidth is reduced
Solution Approach 1:
The patent implements a dynamic regenerative amplification mechanism where the regeneration time is programmably controlled to achieve different gain levels. The cross-coupled pairs are activated for specific time intervals to provide regenerative gain only when needed, allowing wide gain variation without the bandwidth limitations of conventional continuous-time amplifiers.
Solution Approach 2:
The amplifier uses periodic switching of the cross-coupled pairs to achieve regenerative amplification. By controlling the duration and timing of the regenerative phase within each period, the system can achieve wide gain ranges while maintaining constant bandwidth, as the regenerative action occurs in discrete time intervals rather than continuously.
2Power
If conventional programmable-gain amplifier designs are used to achieve high gain, then gain is improved, but power consumption increases
Solution Approach 1:
The cross-coupled pairs are switched periodically rather than remaining continuously active. The regenerative amplification occurs only during specific time intervals controlled by the timing circuit, allowing high gain to be achieved when needed while minimizing power consumption during non-regenerative periods.
Solution Approach 2:
The amplifier discards the continuous operation mode and recovers energy by using regenerative amplification only when required. The cross-coupled pairs are activated briefly to provide the necessary gain, then deactivated to reduce power consumption, achieving high gain with low average power consumption.
3Measurement precision
If conventional programmable-gain amplifier designs are used to achieve dB-linear gain control, then gain control linearity is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex analog gain control mechanisms with a digital timing control system. By controlling the duration of the regenerative phase through digital timing circuits, dB-linear gain control is achieved with simpler circuitry, as the exponential gain characteristic naturally arises from the regenerative process rather than requiring complex analog control networks.
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 solution provides dB-linear gain control, high gain, wide bandwidth, and low power consumption, with measurements demonstrating a gain range of 15 dB to 66 dB over 50 MHz bandwidth and a gain-bandwidth product of up to 100 GHz with 420 μW power consumption.
Implementation Method 1
a negative resistor including two cross-coupled pairs with a differential arrangement
Data Source
AI summary
A programmable-gain amplifier includes: two complementary cross-coupled transistor pairs mutually coupled with each transistor in one pair having a current flow path cascaded with a current flow path of a respective one of the transistors in the other pair. First and second coupling points are formed between the pairs; with first and second sampling capacitors coupled thereto. First and second input stages have input terminals to input signals for sampling by the first and second sampling capacitors. Switching means couple the first and second input stages to the sampling capacitors so the input signals are sampled as sampled signals on the sampling capacitors. The switching means energizes the complementary cross-coupled transistor pairs so the signals sampled on the sampling capacitors undergo negative resistance regeneration growing exponentially over time to thereby provide an exponential amplifier gain.