Duty-Cycled ADC Foreground Calibration Across Standby Periods
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Solution Overview
Problem
Existing duty-cycled analog-to-digital converters (ADCs) face challenges in optimizing foreground calibration due to insufficient time during standby periods and modulation of power supply current duty cycles, which can affect system operation and performance.
Innovation Solution
The proposed solution involves a programmable control system for foreground calibration, allowing configuration of calibration time slots, measurement averages, and periodicity during duty-cycled operation, enabling flexible calibration scheduling and minimizing the impact on power supply current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If foreground calibration is performed during standby period in duty-cycled ADC operation, then calibration accuracy can be improved, but the standby period duration is insufficient to complete the calibration process
Solution Approach 1:
The calibration process is divided into multiple calibration portions that are executed across multiple standby periods. Each calibration portion performs a subset of the required calibration measurements and computations, allowing the complete calibration cycle to be distributed over time rather than requiring a single long standby period.
Solution Approach 2:
The calibration is performed periodically by utilizing each standby period as an opportunity to execute a calibration portion. The calibration controller manages multiple calibration cycles, where each cycle consists of several calibration portions executed in different standby periods, eventually completing the full calibration process.
2Ease of operation
If foreground calibration is performed during duty-cycled operation, then calibration can be done without affecting system operation, but power supply current is modulated which affects system performance
Solution Approach 1:
The calibration portions are extracted and executed specifically during standby periods when the ADC is not performing analog-to-digital conversions. This separates the calibration function from the normal conversion operation, allowing calibration to proceed without interfering with system operation while confining current modulation to periods when conversions are not occurring.
3Loss of time
If calibration process is spread across multiple duty-cycle periods, then insufficient standby time is compensated, but calibration complexity increases
Solution Approach 1:
The calibration controller tracks the progress of the calibration process across multiple standby periods, managing which calibration portions have been executed and coordinating the accumulation of calibration data. This feedback mechanism automates the complex multi-period calibration process, reducing the burden on external control systems.
Data Source
AI summary
An analog-to-digital conversion (ADC) system is operated with a duty cycle. During the ON period, the ADC circuits perform analog-to-digital conversions of an analog input signal. During the Standby period, the ADC system is in either a standby state or a foreground calibration state. The ADC system operates in a reduced-power mode in the standby state. In the foreground calibration state, the ADC system performs a portion of a foreground calibration cycle during a calibration time slot. The foreground calibration cycle is performed over multiple calibration time slots. The foreground calibration cycle and the calibration time slots are configurable by changing the values of control registers that represent calibration parameters.