Current Calibration Device for Power Supply Channels in Test Systems
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Solution Overview
Problem
Traditional current calibration methods for power supply channels in test systems are limited to single-point or few voltage ranges, resulting in incomplete coverage and significant measurement errors due to device offset and inherent deviations under different voltages.
Innovation Solution
A current calibration device and method utilizing n power supply channels, m resistors with different resistance values, a VBIAS power supply, and a host computer to perform segmented calibration through software algorithms, allowing for precise adjustment of output voltages and measurement of current errors across a range of voltages, enabling accurate current calibration under various voltage specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional single-point calibration method is used with fixed current-limiting resistor, then calibration process is simple, but measurement accuracy deteriorates under different voltage specifications
Solution Approach 1:
The voltage range is segmented into multiple calibration points (e.g., 0V, 2.5V, 5V) instead of using a single calibration point. The calibration device performs separate calibration at each voltage point and stores corresponding correction values, which are then applied during actual measurements based on the operating voltage, thereby maintaining high accuracy across the full voltage range.
Solution Approach 2:
The calibration system dynamically adapts to different voltage conditions by selecting appropriate calibration data based on the current operating voltage. The correction values are voltage-dependent and automatically selected during measurement, making the calibration system dynamic rather than static, thus maintaining accuracy across varying voltage specifications.
2Device complexity
If fixed current-limiting resistor is used for calibration, then device complexity is reduced, but voltage coverage becomes incomplete
Solution Approach 1:
The calibration approach is segmented into multiple discrete voltage points rather than attempting continuous calibration. Each segment corresponds to a specific voltage range, and the system selects the appropriate calibration data based on which segment the current voltage falls into, thereby achieving complete voltage coverage through discrete segments.
Solution Approach 2:
The calibration system changes the calibration parameter (correction value) based on the operating voltage. Different voltage ranges have different correction values stored in memory, and the system automatically selects the appropriate correction value based on the current voltage, enabling adaptability across different voltage specifications without changing the physical hardware structure.
3Measurement precision
If multi-point calibration across full voltage range is implemented, then current measurement accuracy is improved, but calibration time increases
Solution Approach 1:
The calibration process is performed in advance during device manufacturing or setup, and the correction values are stored in memory for later use. This preliminary calibration action eliminates the need for time-consuming calibration during actual operation, as the system simply retrieves pre-computed correction values based on the operating voltage.
Solution Approach 2:
Instead of performing continuous calibration across the entire voltage range during operation, the system performs calibration at discrete key points (excessive sampling at critical points) and uses interpolation or direct lookup for intermediate values. This partial calibration approach achieves sufficient accuracy while significantly reducing calibration time compared to continuous calibration.
Data Source
AI summary
The present invention disclosures a current calibration device for power supply channels in a test system, comprising n power supply channels, n connection switches corresponding to the n power supply channels, m resistors, m selection switches corresponding to the m resistors, a VBIAS power supply, a SPI bus, a host computer and an ammeter, wherein, both n and m are integers greater than 0; one end of each of the n power supply channels is connected to the SPI bus, and another end of each of the n power supply channels is connected to a node Q through a connection switch correspondingly, both ends of the selection switch are connected respectively to the node Q and one end of the resistor, and another end of the resistor is connected to the positive terminal of the ammeter, and the negative terminal of the ammeter is connected to the VBIAS power supply, and the VBIAS power supply is connected to the SPI bus simultaneously. The present invention provides a current calibration device and a current calibration method for power supply channels in a test system, which realizes segmented calibration through a software algorithm and improves measurement accuracy of the power supply channels; and solves a problem that a traditional current calibration for power supply channels can only cover a single point or a few voltage ranges.