Sigma-Delta Voltage Measurement with Shared Integrator Amplifier
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Solution Overview
Problem
Existing voltage measurement circuits for battery cells in electric vehicles face challenges in increasing ADC order to improve accuracy and reduce measurement time without increasing the number of amplifiers, leading to larger circuit sizes and slower measurement speeds.
Innovation Solution
A voltage measurement apparatus utilizing a sigma-delta analog-to-digital converter (ADC) with a primary and secondary integrator circuit, a comparator, and a digital filter, where a single amplifier is used sequentially across both circuits to achieve the effect of increased ADC order without requiring additional amplifiers, allowing for improved accuracy and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the order of the ADC is increased to improve voltage measurement accuracy and reduce measurement time, then the measurement precision and productivity are improved, but the number of amplifiers required increases, leading to increased device complexity and area
Solution Approach 1:
The patent combines multiple amplifier functions into a single amplifier by integrating the primary integrator circuit and secondary integrator circuit. The single amplifier sequentially performs integration operations for both circuits, reducing the total number of amplifiers while maintaining the functionality of a higher-order ADC system.
Solution Approach 2:
The single amplifier is designed to serve multiple functions by sequentially operating with different integrator circuits. It functions as the integrator amplifier for the primary integrator circuit during first integration, and then as the integrator amplifier for the secondary integrator circuit during second integration, achieving multi-functionality with a single component.
2Measurement precision
If the number of amplifiers is increased to increase the order of the ADC, then the measurement precision is improved, but the area of the circuit increases
Solution Approach 1:
The patent merges the amplifier components of the primary and secondary integrator circuits into a single shared amplifier. This consolidation significantly reduces the total circuit area while preserving the measurement precision benefits of a higher-order ADC configuration through sequential operation of the single amplifier with different integrator circuits.
3Measurement precision
If the number of amplifiers is increased to increase the order of the ADC, then the measurement precision is improved, but the switching speed and measurement time are reduced
Solution Approach 1:
The patent employs periodic switching between the primary integrator circuit and secondary integrator circuit using the single amplifier. The amplifier alternates between serving the first integration stage and the second integration stage in a time-division manner, enabling the system to achieve high-order ADC precision while maintaining fast switching speeds through periodic operation rather than requiring multiple simultaneously operating amplifiers.
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AI summary
Disclosed herein is an apparatus for measuring a voltage including a primary integrator circuit configured to operate as a first integral stage of a sigma-delta analog-to-digital converter (ADC) circuit by a switching according to a control signal of a controller, a secondary integrator circuit configured to operate as a second integral stage by a switching of the controller, a comparator configured to compare final voltages modulated through the primary integrator circuit and the secondary integrator circuit, and a digital filter configured to delay an output of the comparator by a specified number of clocks according to a switching of the controller, pass the delayed output through a digital-to-analog converter (DAC) to feed the delayed output back to the primary and secondary integrator circuits, and receive the delayed output signal of the comparator as an input, wherein an output of the digital filter becomes a final measured value.