Multi-Input ADC Using a Shared TDC to Cut Area Mismatch
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Solution Overview
Problem
Conventional multiple-input analog-to-digital converters require multiple circuits for simultaneous conversion, leading to increased semiconductor area and process-dependent inconsistencies due to mismatch in timing and conversion efficiency.
Innovation Solution
A single time-to-digital converter (TDC) based on a ring oscillator with an even number of delay units is used for multiple simultaneous analog-to-digital conversions, reducing semiconductor area and process-dependent inconsistencies by sharing the TDC across multiple conversion blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate ADC circuits are used for simultaneous conversion of multiple signals, then conversion capability is improved, but semiconductor area increases
Solution Approach 1:
Multiple ADC conversion blocks share a single common TDC circuit for time measurement. The TDC is time-division multiplexed across multiple conversion blocks, allowing simultaneous conversion of multiple analog signals while using only one TDC instance, thereby reducing semiconductor area while maintaining multi-signal conversion capability
Solution Approach 2:
The single TDC circuit is designed to serve multiple ADC conversion blocks universally. The same TDC infrastructure (ring oscillator, delay units, counter) is reused across different conversion blocks through time-division multiplexing, enabling one component to perform multiple functions for different signal channels
2Adaptability or versatility
If multiple separate ADC circuits are used for simultaneous conversion, then conversion capability is improved, but process-dependent inconsistencies increase
Solution Approach 1:
By merging the TDC function into a single shared circuit rather than having separate TDCs in each ADC block, the patent eliminates process variations between multiple TDC implementations. The common TDC provides consistent time measurement across all conversion blocks, reducing mismatch due to process variations while maintaining the ability to convert multiple signals simultaneously
3Area of stationary object
If a single TDC is shared across multiple conversion blocks, then semiconductor area is reduced, but timing control complexity increases
Solution Approach 1:
The shared TDC is activated periodically for each conversion block in a time-division multiplexed manner. Control signals enable the TDC at specific times for specific conversion blocks, allowing multiple blocks to share the single TDC resource through periodic activation cycles, thus managing timing control while reducing area
4Device complexity
If conventional separate ADC circuits are used, then timing control is simpler, but semiconductor area increases
Solution Approach 1:
The patent implements periodic activation of the shared TDC for different conversion blocks. Control logic enables the TDC at specific periodic intervals for each block, providing structured timing control that manages the complexity of sharing while achieving area reduction through time-division multiplexing
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 enables efficient simultaneous conversion of multiple analog signals into digital format with reduced semiconductor area and improved consistency, addressing the limitations of conventional methods by utilizing a single TDC for multiple conversions.
Implementation Method 1
a time-to-digital converter (TDC) based on a ring oscillator with an even number of delay units
Data Source
AI summary
A multiple-input analog-to-digital converter device includes analog-to-digital converter circuits arranged between input nodes and output nodes. The analog-to-digital converter circuits operate over respective conversion times to provide simultaneous conversion of the analog input signals into respective conversion time signals. A time-to-digital converter circuit includes timer circuitry common to the plurality of analog-to-digital converter circuits. The timer circuitry cooperates with the analog-to-digital converter circuits to convert the conversion time signals into digital output signals at the output nodes.