Wideband Single-to-Differential Converter With Phase Balancing
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Solution Overview
Problem
Existing single-to-differential converters face challenges in achieving wideband performance with low power consumption and desirable phase noise performance, particularly in high-frequency applications like software-defined radio architectures, due to trade-offs in gain, bandwidth, and current consumption.
Innovation Solution
A single-to-differential converter design comprising a single-to-differential stage, a phase balancing stage, and a buffer stage, utilizing CMOS digital gates and a specific configuration of inverters and amplifiers to balance and reshape signals, achieving balanced and shaped output signals with reduced current consumption and improved phase noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the bandwidth of the single-to-differential converter is increased with higher quiescent currents, then the bandwidth is improved, but the power consumption increases
Solution Approach 1:
The patent changes the operating parameters by using lower quiescent currents while maintaining wideband performance through a different circuit topology (current reuse architecture) that efficiently utilizes the available current, thereby reducing power consumption without sacrificing bandwidth
2Power
If the aspect ratio of transistor devices M1 and M2 is increased to maximize gain for a given quiescent current, then the gain is improved, but the output capacitance increases resulting in lower frequency response performance
Solution Approach 1:
The patent optimizes the transistor aspect ratios to balance gain and frequency response, using a different circuit configuration that achieves high gain without excessive output capacitance by utilizing current reuse mechanisms and optimized device sizing
3Power
If larger load resistance of RL is used to maximize gain, then the gain is improved, but the output swing is reduced due to large voltage drops across it
Solution Approach 1:
The patent uses optimized load resistance values that balance gain and output swing requirements, achieving high gain while maintaining sufficient output voltage swing through careful parameter selection and current reuse architecture
4Reliability
If differential pair transconductance amplifiers are used in the single-to-differential converter, then the phase noise performance is improved, but achieving wide-band performance becomes difficult
Solution Approach 1:
The patent employs a dynamic current reuse architecture that adapts the circuit operation across wide frequency ranges while maintaining low phase noise, using switching mechanisms and time-varying operating conditions to achieve both wideband performance and low phase noise
Data Source
AI summary
A method and apparatus for single-to-differential conversion includes a single-to-differential stage (22), a phase balancing stage (24), and a buffer stage (26). The single-to-differential stage (22) converts a single input signal (Vclk) to a first and second output signal (Vn, Vp), where the first and second output signals (Vn, Vp) correspond to one another. The phase balancing stage (24) is electrically connected to the single-to-differential stage (22), balances and receives the first and second output signals (Vn, Vp), and outputs first and second balanced output signals (V+, V−). The buffer stage (26) is electrically connected to the phase balancing stage (24) for shaping the first and second balanced output signals (V+, V−). The single-to-differential converter (20) is operable over a substantially large bandwidth and achieves low-power consumption and good phase noise performance.