Mixed-Voltage Interface Serial Data Transfer ESD Protection
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Solution Overview
Problem
Mixed-voltage semiconductor integrated circuits face significant space occupancy issues due to the large area required by ESD protection circuits, which are necessary to prevent electrostatic destruction across different voltage domains, especially as the number of signal lines increases.
Innovation Solution
Implementing a mixed-voltage interface that transfers data between circuit blocks operating at different voltage levels through serial data transfer on a single signal line instead of parallel transfer, significantly reducing the number of required interface signal lines and consequently the area occupied by ESD protection circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate ESD protection circuits are provided for each interface signal line, then ESD protection reliability is improved, but the area occupied by ESD protection circuitry increases significantly
Solution Approach 1:
The patent merges multiple ESD protection functions into a single shared ESD protection circuit that serves multiple signal lines. Instead of providing separate ESD protection circuits for each signal line crossing the voltage boundary, the invention uses one ESD protection circuit that can protect multiple lines simultaneously, thereby significantly reducing the area occupied while maintaining ESD protection reliability.
Solution Approach 2:
The ESD protection circuit is designed with multi-functionality to protect multiple signal lines from different voltage domains. The circuit can identify and respond to ESD events on any of the protected signal lines, making it a universal protection solution that replaces multiple dedicated circuits, thus reducing overall chip area.
2Productivity
If parallel data transfer is used on multiple signal lines, then data transfer speed is improved, but the number of ESD protection circuits required increases
Solution Approach 1:
The patent replaces the mechanical approach of using multiple parallel signal lines with a single serial communication interface. By substituting parallel data transfer with serial data transfer, the invention reduces the number of signal lines required for data communication, which directly reduces the number of ESD protection circuits needed while maintaining adequate data transfer capabilities.
Solution Approach 2:
The invention transitions from a spatial parallel arrangement of multiple signal lines to a temporal serial arrangement of data transmission. Instead of transmitting multiple bits simultaneously across different lines, the system transmits bits sequentially over time on a single line, reducing the number of physical connections and corresponding ESD protection requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the number of ESD protection circuits and the area they occupy, enhancing the efficiency of ESD protection while minimizing space usage on large-scale integrated circuits.
Implementation Method 1
ESD protection can be provided by, for example, simple diode circuits that shunt current from input and output signal lines to the power supply or ground when the voltages on the signal lines become abnormally high or low.
Data Source
AI summary
A mixed-voltage interface transfers signals serially between a pair of circuit blocks operating at different voltage levels in a semiconductor integrated circuit. Control, address, and data signals are multiplexed onto a common signal line. The number of necessary signal lines is thereby greatly reduced, as compared with parallel signal transfer, and a separate electrostatic discharge protection circuit can be provided for each signal line without the need to devote excessive space to protection circuitry.