I/O Circuit Back-Gate Control for High-Voltage Input Handling
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Solution Overview
Problem
Conventional input/output circuits face increased power consumption and reduced operation speed due to slow response times of output transistors and unnecessary current path formation when handling high voltage input signals, especially in high-frequency data operations.
Innovation Solution
An input/output circuit design that includes a pull-up and pull-down output transistor, logic circuits, and a back gate control circuit, which maintains the pull-up transistor inactive during high voltage input and disconnects power supply to logic circuits, preventing current paths and optimizing back gate voltage to reduce power consumption and enhance operation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tolerant input/output circuit uses conventional output transistors and transfer gates to handle high voltage input signals, then the circuit can operate with high voltage inputs, but unnecessary current paths are formed and power consumption increases
Solution Approach 1:
The patent introduces a back gate control circuit that acts as an intermediary to control the potential of the back gates of output transistors. When a high voltage input signal is detected, the back gate control circuit adjusts the back gate potential to prevent the formation of unnecessary current paths, thereby reducing power consumption while maintaining the ability to handle high voltage inputs.
Solution Approach 2:
The patent changes the potential parameter of the back gates of output transistors dynamically. By adjusting the back gate potential based on the input signal voltage level, the circuit prevents current leakage paths without requiring additional switching elements, thus reducing power consumption while maintaining high voltage compatibility.
2Device complexity
If the output transistors respond slowly to gate potential changes, then the circuit structure remains simple, but the operation speed decreases and cannot keep up with high-frequency data
Solution Approach 1:
The back gate control circuit serves as an intermediary that accelerates the response of output transistors. By controlling the back gate potential, it enables faster switching of output transistors without adding complex circuit structures, thus improving operation speed while maintaining relative simplicity.
Solution Approach 2:
The back gate control circuit performs preliminary action by pre-adjusting the back gate potential in anticipation of signal changes. This preliminary adjustment reduces the response time of output transistors, enabling them to keep up with high-frequency data without requiring fundamentally more complex circuit structures.
3Stability of the object's composition
If the gate potential waveform contains inflection points during transitions, then the transistor switching is smoother, but the operation speed decreases and power consumption increases
Solution Approach 1:
The back gate control circuit changes the potential parameter dynamically to eliminate inflection points in the gate potential waveform. By directly controlling the back gate potential to match the timing of input signal changes, the circuit achieves smooth transistor switching without inflection points, thereby maintaining both stability and high operation speed.
Data Source
AI summary
An input/output circuit operable in input and output modes and including an input/output terminal, pull-up and pull-down output transistors, and first and second logic circuits operated in accordance with data and an enable signal. A control circuit maintains the pull-up output transistor in an inactivated state regardless of the voltage applied to the input/output terminal in the input mode. A switch circuit disconnects the first logic circuit from a power supply when an input signal having voltage higher than the power supply voltage of the power supply is input to the input/output terminal in the input mode. A back gate control circuit supplies back gates of P-channel MOS transistors in the first logic circuit and the switch circuit with back gate voltage having the same voltage as the input signal when the input signal is input in the input mode.