On-Chip Scope Circuit for Low-Loading Analog Node Debug
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Debugging integrated circuits is challenging due to the loading effect of wires and pads on internal analog nodes, which requires a small, low-power on-chip oscilloscope that can be instantiated multiple times without consuming excessive chip area or power.
Innovation Solution
A sampling circuit with a cross-bar switch, differential comparator, multiplexer, counter, and control circuit that estimates voltages at specific phases of a periodic signal by switching reference voltages and calculating corrected estimates, reducing the impact of voltage offsets and loading effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If internal analog nodes are brought out to pads for debugging, then signal observation is enabled, but loading effect from wires and pads degrades signal integrity
Solution Approach 1:
The patent introduces an on-chip oscilloscope as an intermediary device that measures internal analog nodes directly on the chip without requiring external pad connections. This mediator captures signals at their source, eliminating the loading effect of external wires and pads while preserving signal integrity for debugging purposes
2Measurement precision
If sampling or amplification circuits are added to sense internal nodes, then signal observation is improved, but chip area and power consumption increase
Solution Approach 1:
The patent merges multiple functions (sampling, amplification, and oscilloscope operations) into a single integrated on-chip oscilloscope unit. This consolidation eliminates the need for separate sampling or amplification circuits, achieving effective signal sensing while minimizing chip area consumption through functional integration
Solution Approach 2:
The on-chip oscilloscope is designed as a universal debugging tool that can observe multiple internal analog nodes across different circuits. This multi-functional capability replaces the need for dedicated sampling or amplification circuits for each specific node, reducing overall chip area while maintaining comprehensive signal observation
3Measurement precision
If sampling or amplification circuits are added to sense internal nodes, then signal observation is improved, but power consumption increases
Solution Approach 1:
The patent merges multiple functions (sampling, amplification, and oscilloscope operations) into a single integrated on-chip oscilloscope unit. This consolidation eliminates the need for separate sampling or amplification circuits, achieving effective signal sensing while minimizing chip area consumption through functional integration
Solution Approach 2:
The on-chip oscilloscope is designed as a universal debugging tool that can observe multiple internal analog nodes across different circuits. This multi-functional capability replaces the need for dedicated sampling or amplification circuits for each specific node, reducing overall chip area while maintaining comprehensive signal observation
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
Enables efficient, low-overhead on-chip oscilloscope implementation that accurately characterizes internal signals with reduced loading and power consumption, facilitating effective debugging of high-speed circuits.
Implementation Method 1
a differential comparator, the cross-bar switch being connected between: the sampling input and the reference input, and the differential comparator
Data Source
AI summary
An on-chip scope and a method for operating the on-chip scope. The on-chip scope includes a provision for operating in one of two states, the effects of voltage offsets being different in the two states. A first voltage is measured in the first state, a second voltage is measured in the second state, and the two measurements are combined to generate a voltage estimate in which the effects of voltage offsets are reduced.