Inverter-Based ADC Threshold Compensation for Low-Power Dynamic Range
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Solution Overview
Problem
Conventional Analog to Digital Converters (ADCs) face challenges in achieving high dynamic range, low power consumption, and low cost, particularly in ultra-deep submicron CMOS technology, due to high power consumption and conversion latency, which is undesirable for wireless and wireline communications.
Innovation Solution
The design employs an inverter-based ADC with a dynamic discrete time architecture, using NMOS and PMOS devices to reduce power consumption by connecting the input signal to the NMOS devices only after a pre-charge cycle, and incorporates temperature and voltage compensation to adjust device thresholds and conversion times, optimizing device selection and error correction for improved yield and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional ADC architectures are used to achieve high conversion rates, then conversion speed is improved, but power consumption increases significantly
Solution Approach 1:
The ADC is divided into multiple sub-ADCs operating in parallel with time-interleaved architecture. Each sub-ADC handles a portion of the conversion tasks, allowing higher overall conversion rates without proportionally increasing power consumption of each individual unit. The segmentation enables distribution of computational load across multiple lower-power components.
Solution Approach 2:
The invention employs periodic pre-charging of capacitors at specific intervals before conversion cycles. This periodic action prepares the circuit state in advance, reducing the energy required during actual conversion operations. The pre-charge phase occurs periodically at controlled times, enabling efficient energy utilization during high-speed conversion periods.
2Ease of manufacture
If device scaling is used to lower cost and improve digital logic performance, then manufacturing cost is reduced, but analog design parameters such as linearity and dynamic range deteriorate
Solution Approach 1:
The invention introduces temperature and voltage compensation mechanisms that dynamically adjust operating parameters to maintain optimal analog performance. By monitoring and compensating for parameter variations caused by device scaling, the system maintains linearity and dynamic range specifications even when using scaled transistors with shorter channel lengths and thinner oxides.
Solution Approach 2:
Temperature and voltage sensing circuits provide feedback to compensation logic that adjusts device thresholds and conversion times. This feedback mechanism counteracts the adverse effects of device scaling on analog parameters, ensuring consistent performance across process variations and enabling use of cost-effective scaled technologies.
3Speed
If minimum channel length transistors are used to improve transition frequency, then operation speed is improved, but power consumption and analog performance parameters worsen
Solution Approach 1:
The invention dynamically selects and switches between different transistor devices based on operating conditions, temperature, and voltage levels. This dynamic device selection optimizes the balance between speed and power consumption by activating only the necessary number of high-frequency transistors when needed, rather than continuously operating all minimum-channel-length devices at full power.
Solution Approach 2:
Pre-charging of capacitive elements is performed in advance before conversion operations begin. This preliminary action reduces the energy required during active conversion phases by minimizing the voltage swing and charging/discharging requirements of critical nodes, thereby reducing power dissipation while maintaining high transition frequencies.
4Measurement precision
If conventional ADC designs are used to achieve high dynamic range, then conversion accuracy is improved, but conversion latency increases
Solution Approach 1:
The high dynamic range conversion process is segmented into multiple parallel sub-conversions handled by time-interleaved sub-ADCs. Each sub-ADC processes a portion of the signal simultaneously, reducing the overall conversion time while maintaining the cumulative dynamic range through combination of multiple measurements. This segmentation eliminates the need for sequential processing that would increase latency.
Data Source
AI summary
Methods and systems 10 are provided for circuits. One method is for increasing device threshold voltage distribution of a plurality of devices of a circuit. The method includes adjusting a device threshold voltage of the plurality of devices by different amounts; and selecting a subset of the plurality of devices with adjusted device threshold voltage by a device selection module for performing a function associated with the circuit. In one aspect, a system for device threshold voltage adjustment is provided. The system includes a sensor module for sensing one or more of temperature and voltage values of a die having a plurality of devices for a circuit; and a threshold temperature and voltage compensation module for receiving an input value from the sensor module to compensate variation in a device threshold voltage caused by changes of one or more of temperature and voltage of the die.