Time-Interleaved Slope ADC Using a Shared Asynchronous Ramp
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing time-interleaved analog-to-digital converters (ADCs), particularly SAR-ADCs, face limitations in speed due to area requirements and complex reference voltage distribution, especially when implemented in parallel for high-speed applications.
Innovation Solution
Implementing a time-interleaved ADC system using smaller and slower slope ADCs, synchronized asynchronously to a common slope signal, which generates a single global slope signal for multiple ADCs, allowing for high-speed conversion with simplified reference signal generation and reduced area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If SAR-ADCs are implemented in parallel to increase conversion speed, then conversion speed is improved, but area requirements increase significantly
Solution Approach 1:
The system divides the high-speed conversion task into multiple parallel SAR-ADC channels, each operating at a lower individual speed. By segmenting the conversion process across N parallel channels with time-interleaved sampling, the overall conversion speed reaches N times the individual channel speed, while each channel uses a smaller, more area-efficient design.
Solution Approach 2:
The patent transitions from a single-channel time-domain speed optimization to a multi-channel parallel architecture. By adding the dimension of parallel channels and using time-interleaved sampling with staggered clocks, the system achieves high overall conversion speed without requiring each individual ADC to operate at maximum speed, thereby reducing area requirements.
2Speed
If multiple SAR-ADCs are implemented in parallel, then conversion speed is improved, but reference voltage distribution complexity increases
Solution Approach 1:
The reference voltage distribution network is segmented into N separate networks, one for each parallel SAR-ADC channel. Each channel receives its own dedicated reference voltage through its own distribution network, eliminating the need for a single complex distributed reference system and reducing overall distribution complexity.
Solution Approach 2:
The patent resolves reference voltage distribution complexity by moving from a single shared reference system to multiple independent reference systems distributed across parallel channels. This dimensional separation allows each channel to have simplified, localized reference voltage distribution while maintaining high overall conversion speed.
3Area of stationary object
If slope ADCs with greater number are used, then area requirements are reduced, but ramp signal generation complexity increases
Solution Approach 1:
The ramp signal generation is segmented and distributed to each slope ADC channel individually. Instead of generating one complex synchronized ramp signal for all channels, each channel generates its own local ramp signal independently, simplifying the overall ramp generation architecture while maintaining area efficiency.
Solution Approach 2:
The patent resolves ramp signal generation complexity by transitioning from a centralized synchronized ramp generation system to distributed independent ramp generation across parallel channels. This dimensional distribution eliminates synchronization requirements and reduces overall system complexity while maintaining the area benefits of multiple slope ADCs.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A slope analog-to-digital converter (200) is provided. The slope analog-to-digital converter comprises a sample and hold stage (210) configured to sample an analog input signal at a sampling frequency, a comparator (220) downstream to the sample and hold stage (210) configured to compare the analog input signal to a slope signal, and a digital logic (230) configured to receive a counter value corresponding to a voltage level of the slope signal and to sample the counter value based upon the comparison, thereby generating a digital representation of the analog input signal based upon the comparison. In this context, the slope signal is asynchronous to the sampling frequency.