Integrated Logic Circuit Level Shifting With Switched Supply Rails
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Solution Overview
Problem
Existing logic circuits for level shifting between different voltage levels in semiconductor technology often increase circuit area, power consumption, and decrease operation speed, especially when used in combinational logic units.
Innovation Solution
A logic circuit design incorporating a logic gate unit, an inverter, and switching circuits with PMOS transistors that dynamically switch between two power supply voltages, allowing level shifting without significantly expanding the circuit area by using only two additional transistors to manage the voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a level shifter is used to connect two logic units operating at different voltage levels, then voltage level shifting capability is improved, but circuit occupation area increases
Solution Approach 1:
The patent merges the level shifting function with the existing logic gate structure by integrating switching circuits directly into the logic gate unit. The switching circuits are combined with the logic gate transistors to share common nodes and signal paths, allowing the logic gate to operate at different voltage levels without requiring a separate dedicated level shifter circuit.
Solution Approach 2:
The logic gate unit is designed to perform multiple functions: it can operate as a standard logic gate at a first voltage level and simultaneously function as a level shifter to output signals at a second voltage level. The switching circuits enable the logic gate to adapt its output voltage level based on control signals, making the circuit versatile for different voltage domain requirements.
2Adaptability or versatility
If a level shifter is used to connect two logic units operating at different voltage levels, then voltage level shifting capability is improved, but power consumption increases
Solution Approach 1:
The switching circuits are controlled by clock signals to periodically switch between different voltage levels. The switching occurs only during specific clock cycles when level shifting is required, rather than continuously operating, which reduces unnecessary power consumption while maintaining voltage level shifting capability when needed.
3Adaptability or versatility
If a level shifter is used to connect two logic units operating at different voltage levels, then voltage level shifting capability is improved, but operation speed decreases
Solution Approach 1:
The switching circuits are prepared and pre-configured within the logic gate structure, with switching transistors already positioned and connected to the logic gate nodes. The switching action is triggered by clock signals that are synchronized with the logic operation timing, allowing the voltage level transition to occur in advance or simultaneously with the logic operation rather than adding sequential delay.
Data Source
AI summary
A logic circuit includes a logic gate unit, an inverter, and a switching circuit. The logic gate unit receives a power supply voltage and an input signal to output a first signal. The inverter receives the first signal to output a second signal. The switching circuit provides one of first and second power supply voltages as the power supply voltage of the logic gate unit in response to the first and second signals. The first power supply voltage and the second power supply voltage have different voltage levels, thus enabling stable level shifting.