Swing Level Conversion Circuit for CML-CMOS Signal Compatibility
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Solution Overview
Problem
Semiconductor apparatuses face challenges in efficiently converting signal levels between current mode logic (CML) and complementary metal-oxide semiconductor (CMOS) levels, particularly in high-speed operations where power efficiency is compromised due to differing signal swing widths.
Innovation Solution
A semiconductor apparatus with an input selection circuit that chooses between CML and CMOS input signals based on control signals and a conversion circuit that generates an output signal at a level substantially identical to the CMOS level, incorporating capacitors and logic gates to perform inverting and resistive feedback operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If signal conversion between CML and CMOS levels is implemented, then signal level compatibility is achieved, but power consumption increases
Solution Approach 1:
The patent implements dynamic selection between CML and CMOS signal paths based on operating speed requirements. The apparatus can switch between different input circuits (first for CML, second for CMOS) and different output circuits (third for CML, fourth for CMOS) depending on whether high-speed or low-speed operation is needed, avoiding unnecessary signal conversion and reducing power consumption.
Solution Approach 2:
The patent applies different signal level configurations to different parts of the apparatus based on functional requirements. High-speed functional blocks use CML signaling while low-speed blocks use CMOS signaling, allowing each part to operate at its optimal signal level without forcing conversion across the entire system.
2Speed
If CML level signals are used for high-speed operation, then operating speed increases, but power efficiency decreases
Solution Approach 1:
The apparatus dynamically switches between CML and CMOS signal paths based on the required operating speed. When high-speed operation is needed, the system selects the CML input circuit and CML output circuit. When low-speed operation suffices, it selects the CMOS input circuit and CMOS output circuit, optimizing power efficiency for the current performance requirement.
3Adaptability or versatility
If signal swing levels are maintained for both high-speed and low-speed operations, then operational versatility is improved, but device complexity increases
Solution Approach 1:
The patent divides the signal processing path into separate segments for CML and CMOS operations. It includes a first input circuit for CML signals, a second input circuit for CMOS signals, a third output circuit for CML signals, and a fourth output circuit for CMOS signals. This segmentation allows independent optimization of each path while maintaining versatility through selective activation.
Solution Approach 2:
The apparatus is designed with multi-functional capability to handle both CML and CMOS signal levels through different input and output circuits. The control circuit universally manages the selection between these different signal paths, allowing a single apparatus to perform both high-speed CML operations and low-speed CMOS operations without requiring separate dedicated hardware for each mode.
Data Source
AI summary
A semiconductor apparatus includes an input selection circuit that selects one of a first input signal and a second input signal in response to a control signal, and outputs the selected input signal as a selection signal, wherein swing levels of the first input signal and the second input signal are different one another. The semiconductor apparatus also includes a conversion circuit that generates an output signal, in response to the selection signal, which swings to a level substantially identical to a level of the second input signal.