Local Multiplexer Circuit for IC Internal Signal Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for monitoring internal signals in integrated circuits face challenges such as scalability issues, increased noise and crosstalk, inefficiency in size and power consumption, and impracticality due to the need for additional external pins and complex communication among circuit blocks.
Innovation Solution
Implementing local multiplexer circuits near circuit blocks with limited input nodes and an OR gate to selectively route internal signals to external pins, reducing noise and power consumption by keeping routing distances short and using a control signal to manage signal selection, and distributing local OR gates to maintain a manageable output OR gate size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If internal signals are routed to external pins for monitoring, then signal observability is improved, but the number of required external pins increases
Solution Approach 1:
A single external pin is made multi-functional by using a multiplexer to select and route different internal signals to it dynamically. The multiplexer allows one pin to serve multiple monitoring purposes by switching between different signal sources based on control inputs.
Solution Approach 2:
A multiplexer is introduced as an intermediary component between internal signals and the external pin. This mediator selectively connects different internal signals to the external pin, enabling monitoring of multiple signals through a single pin interface.
2Quantity of substance
If multiple internal signals are routed to a single external pin via multiplexer, then pin usage is optimized, but noise and crosstalk increase due to long signal traces
Solution Approach 1:
The circuit is divided into multiple segments with local multiplexers distributed throughout. Each local multiplexer handles a specific group of internal signals locally, segmenting the signal routing paths and reducing the length of traces that carry multiple signals.
Solution Approach 2:
The signal monitoring architecture transitions from a centralized single-point collection to a distributed multi-point architecture. By adding spatial distribution as a new dimension, local multiplexers are placed throughout the circuit to collect signals at multiple locations before combining them, thereby reducing trace lengths.
3Difficulty of detecting and measuring
If more internal signals are monitored using traditional routing, then monitoring capability increases, but circuit area and power consumption increase
Solution Approach 1:
Local multiplexers are designed as compact multi-functional units that can monitor multiple internal signals within a small area. Each multiplexer can selectively route different signals to output, providing high monitoring capability with minimal area overhead.
Solution Approach 2:
The architecture changes the routing parameters by using shared output paths from local multiplexers. Instead of dedicated long traces for each signal, multiple signals share common output traces from their respective local multiplexers, reducing total trace area while maintaining monitoring capability.
4Device complexity
If internal signals are routed over long distances to centralized multiplexer, then signal collection is simplified, but power consumption increases
Solution Approach 1:
The signal collection function is segmented and distributed to multiple local multiplexers throughout the circuit. Each local multiplexer performs signal selection locally, eliminating the need for long-distance routing of multiple signals to a single centralized point, thereby reducing power consumption.
Data Source
AI summary
Apparatus and methods are provided for debugging an integrated circuit. Local multiplexer circuits are provided near first and second circuit blocks in the integrated circuit. Each multiplexer circuit includes input nodes, a control node, and an output node. A first input node of the first multiplexer circuit is coupled to an internal node of the first circuit block, a first input node of the second multiplexer circuit is coupled to an internal node of the second circuit block, second input nodes of the first and second multiplexer circuits are coupled to logical 0, and the control signal nodes of the first and second multiplexer circuits are coupled to a control signal. An OR gate is provided that includes an input node coupled to the output node of the first multiplexer circuit, another input node coupled to the output node of the second multiplexer circuit, and an output node. The control signal is used to select the internal nodes of the first or second circuit blocks for monitoring at the output node of the OR gate.