Parallel Data Output Circuit for HiZ Transition Noise Control
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Solution Overview
Problem
Existing semiconductor integrated circuits face challenges in accurately transmitting data due to power-supply noise amplification on signal lines, particularly when data output circuits switch from high impedance mode to data transmission mode, affecting both data receiving and transmitting circuits.
Innovation Solution
A semiconductor integrated circuit design that includes data output circuits capable of outputting fixed data during mode transitions, reducing power-supply noise amplification by using a control circuit to manage the output of data transmitting circuits through a termination circuit with switches and resistors, and a data selection circuit to select and output predetermined data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data output circuits switch from high impedance mode to data transmission mode, then data transmission capability is improved, but power-supply noise amplification occurs on signal lines
Solution Approach 1:
The patent applies preliminary action by outputting fixed data (preliminary data) from data output circuits during the transition period before actual data transmission begins. This preliminary output of fixed data stabilizes the power supply voltage and prevents noise amplification that would occur during the mode switching from high impedance to data transmission mode, thereby resolving the technical contradiction between improving data transmission capability and preventing power-supply noise amplification
2Speed
If multiple data output circuits output data having the same potential at the same time, then data transmission speed is improved, but power-supply noise is amplified
Solution Approach 1:
The patent implements preliminary action by having data output circuits output fixed data before simultaneously outputting actual transmission data. This preliminary fixed data output stabilizes the power supply voltage in advance, preventing the amplification of power-supply noise that would otherwise occur when multiple data output circuits simultaneously switch to outputting data having the same potential, thus resolving the contradiction between transmission speed and noise amplification
Solution Approach 2:
The patent applies parameter changes by altering the output data parameter from fixed data to transmission data after the preliminary phase. This parameter change approach allows the system to first stabilize in a controlled state (outputting fixed data) and then transition to the active transmission state, thereby enabling high-speed simultaneous data output from multiple circuits without causing power-supply noise amplification
Data Source
AI summary
Provided is a semiconductor integrated circuit according to an exemplary aspect of the present invention including a data transmitting circuit that transmits data in parallel through a plurality of signal lines and a data receiving circuit that receives the data. The data transmitting circuit includes a plurality of data output circuits that output the data in a data transmission mode or set an output to a high impedance state in a HiZ mode, a plurality of data selection circuits that select one of the data and fixed data and output the selected data to the data output circuits, and a control circuit that controls the data output circuits to output the fixed data during a period between a time when a mode is switched from the HiZ mode to the data transmission mode and a time when the data output circuits start to output the data.