Semiconductor Memory Input Output Multiplexing for Terminal Reduction
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Solution Overview
Problem
Semiconductor memory devices require a large number of external connection terminals for control signals, complicating control operations and increasing the complexity of the layout of printed circuit boards and controllers.
Innovation Solution
Implementing an input/output multiplexing scheme that allows a semiconductor memory device to recognize input/output signals as either a command, address, or data based on a combination of a reduced number of control signals, thereby reducing the number of external connection terminals needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large number of control signals are used to control the semiconductor memory device, then the control operation can be detailed and precise, but the number of external connection terminals increases and the layout complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling the input/output lines to serve multiple purposes: they can transmit both data signals and command signals depending on the state of control signals. The controller dynamically switches the function of these lines based on whether a write operation or read operation is being performed, thereby reducing the need for separate dedicated control terminals while maintaining precise control capability
Solution Approach 2:
The patent merges the function of separate command control terminals with the input/output data terminals. By combining the command signal transmission capability with the existing input/output lines and using control signals to differentiate between command and data modes, the design reduces the total number of external connection terminals while preserving detailed control functionality
2Ease of operation
If a large number of control signals are used to control the semiconductor memory device, then the control operation can be detailed and precise, but the layout of the printed circuit board becomes more complex
Solution Approach 1:
The input/output lines are designed to perform multiple functions by transmitting different types of signals (data or commands) based on the control signal state. This multi-functionality reduces the number of separate signal paths needed on the PCB, thereby simplifying the layout and reducing the area required for routing while maintaining precise control capabilities
3Device complexity
If the number of control signals is reduced, then the number of external connection terminals is reduced and layout is simplified, but the control operation becomes more complicated
Solution Approach 1:
The controller is designed to automatically determine the function of each input/output line based on the state of the control signals. The system self-manages the differentiation between command and data modes without requiring additional external control terminals, thereby reducing device complexity while maintaining straightforward control operations through intelligent signal interpretation
Data Source
AI summary
A method for operating a semiconductor memory device includes receiving input/output signals including a command, an address and data, through input/output lines; and receiving a first control signal and a second control signal, wherein, regardless of a state of the second control signal, when the first control signal which is enabled is received, the input/output signals received through the input/output lines are recognized as the command.