Comparator Offset Calibration Using Supply Current Control
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Solution Overview
Problem
Comparators face challenges in achieving high accuracy without compromising other characteristics such as power consumption, operating speed, noise properties, and area, due to trade-offs in their design.
Innovation Solution
A comparator with an input circuit, differential amplification circuit, and current valve configured to adjust supply current based on a control signal, allowing for offset calibration without affecting other characteristics, is integrated into an integrated circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the supply current of the differential amplification circuit is increased to improve accuracy, then the offset calibration capability is improved, but the power consumption increases
Solution Approach 1:
The current valve dynamically adjusts the supply current based on operational mode (calibration mode vs. normal mode). During calibration, higher current improves accuracy; during normal operation, reduced current lowers power consumption while maintaining performance through the stored calibration offset.
Solution Approach 2:
The supply current parameter is changed based on operational requirements. The system switches between different current levels: a first supply current during calibration mode for high accuracy offset adjustment, and a second (reduced) supply current during normal mode to minimize power consumption while maintaining the calibrated performance.
2Measurement precision
If the offset adjustment range is widened to improve calibration capability, then the accuracy is improved, but the device complexity increases
Solution Approach 1:
The offset is adjusted by changing the supply current parameter through the current valve, which provides a wide adjustment range. This parameter-based approach avoids the need for complex hardware structures like multiple resistors or capacitors, thereby achieving wide offset calibration capability without significantly increasing device complexity.
3Adaptability or versatility
If the supply current is adjusted frequently to adapt to different operating conditions, then the adaptability is improved, but the operating speed is reduced
Solution Approach 1:
The current adjustment is performed periodically: first during calibration mode to establish the optimal offset, and then in normal mode where the calibrated offset is maintained. This periodic adjustment approach provides adaptability for different operating conditions while minimizing the impact on operating speed, as the current is only adjusted during the calibration phase rather than continuously during normal operation.
Data Source
AI summary
A comparator configured to calibrate an offset according to a control signal, including an input circuit configured to receive a first input signal and a second input signal, and to generate a first internal signal corresponding to the first input signal and a second internal signal corresponding to the second input signal; a differential amplification circuit configured to consume a supply current flowing from a positive voltage node having a positive supply voltage to a negative voltage node having a negative supply voltage, and to generate an output signal by amplifying a difference between the first internal signal and the second internal signal; and a current valve configured to adjust at least a portion of the supply current based on the control signal.