Negative Voltage Conversion Circuit With Offset Calibration
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Solution Overview
Problem
Calibrating negative voltage sources in semiconductor devices is complex due to the need for accurate measurement and conversion of negative voltages, which existing technologies struggle with, especially when using automated test equipment configured for positive voltages.
Innovation Solution
A multi-stage amplifier is used to switch between calibration and operational modes, allowing for negative to positive voltage conversion, and an offset voltage measurement is recorded to correct measurements, enabling accurate calibration and switchover between negative and positive voltage sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If negative voltage sources are calibrated using existing automated test equipment configured for positive voltages, then measurement capability is limited, but calibration accuracy deteriorates
Solution Approach 1:
A multi-stage amplifier is introduced as an intermediary device between the negative voltage source and the automated test equipment. The amplifier converts negative voltages to positive voltages, enabling the positive-voltage-configured test equipment to accurately measure and calibrate negative voltage sources without direct exposure to negative voltage signals.
Solution Approach 2:
The voltage polarity parameter is changed from negative to positive through the multi-stage amplifier conversion process. This parameter transformation allows existing test equipment to operate within its designed positive voltage range while still calibrating negative voltage sources, thereby maintaining measurement precision without requiring equipment reconfiguration.
2Measurement precision
If a multi-stage amplifier is used for negative to positive voltage conversion, then calibration accuracy improves, but device complexity increases
Solution Approach 1:
The voltage conversion function is segmented into multiple stages, with each operational amplifier stage performing a specific conversion task. This segmentation allows for better control and accuracy in the negative-to-positive voltage conversion process, while each individual stage remains relatively simple in design.
Solution Approach 2:
The multi-stage amplifier is designed to perform multiple functions: voltage polarity conversion, signal buffering, and calibration support. By consolidating these functions into a single multi-functional device, the overall system complexity is managed more effectively compared to using separate dedicated components for each function.
3Measurement precision
If offset voltage measurement is recorded to correct measurements, then calibration accuracy improves, but measurement process time increases
Solution Approach 1:
The offset voltage measurement is performed as a preliminary action before the main calibration process. By measuring and recording the offset voltage in advance, the actual calibration measurements can be corrected using this pre-obtained data, improving accuracy without requiring additional time during the critical calibration measurement phase.
Data Source
AI summary
Apparatuses and techniques are described for calibrating a negative voltage source. A ground voltage is applied to a multi-stage amplifier from the negative voltage source while an offset voltage measurement (OVM) is made at the output of the multi-stage amplifier. The OVM is recorded and subsequently used by a calibration circuit when the negative voltage source applies a range of negative voltages to the input of the multiple stage amplifier. The calibration circuit subtracts the OVM from measurements obtained at the output of the multi-stage amplifier to obtain corrected measurements, and uses the corrected measurements to calibrate the negative voltage source, e.g., by adjusting a relationship between digital values input to the negative voltage source and the output voltages.