Dual-Input BMS ADC Architecture for ASIL D Redundancy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems (BMS) face challenges in meeting the ASIL D standard for redundant measurements, which requires duplicate ADCs for each cell, leading to increased die area and power consumption, especially when monitoring large numbers of battery cells.
Innovation Solution
A dual-input Analog Front-End for BMS with shared digital converter circuit and redundant switched capacitor circuits for primary and secondary cell voltage measurements, along with a diagnostic reference circuit to verify functionality, reducing die area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If duplicate ADCs are used for each battery cell to meet ASIL D standard, then measurement redundancy is improved, but die area and power consumption increase
Solution Approach 1:
The patent merges multiple measurement functions into a single ADC by providing multiple input paths (primary measurement input, secondary measurement input, and diagnostic input) that share the same digital converter circuit. This allows one ADC to perform the work of multiple duplicate ADCs while maintaining ASIL D measurement redundancy requirements.
Solution Approach 2:
The ADC is designed with universal input capability to handle different measurement types through a single device. The selection circuit enables the ADC to universally process signals from primary measurement inputs, secondary measurement inputs, or diagnostic reference inputs, making one ADC serve multiple measurement purposes simultaneously.
2Reliability
If duplicate ADCs are used for each battery cell to meet ASIL D standard, then measurement redundancy is improved, but power consumption increases
Solution Approach 1:
The patent merges multiple measurement functions into a single ADC by providing multiple input paths (primary measurement input, secondary measurement input, and diagnostic input) that share the same digital converter circuit. This allows one ADC to perform the work of multiple duplicate ADCs while maintaining ASIL D measurement redundancy requirements.
Solution Approach 2:
The selection circuit enables periodic switching between different input sources (primary measurement, secondary measurement, diagnostic reference) allowing the single ADC to sequentially perform multiple measurement functions, thereby reducing overall power consumption compared to having continuously active duplicate ADCs.
3Area of stationary object
If a single ADC is used for multiple measurement functions, then die area and power consumption are reduced, but measurement redundancy may be compromised
Solution Approach 1:
The selection circuit acts as an intermediary that manages multiple input paths to the single ADC. It ensures that primary and secondary measurement inputs can be independently selected and processed, maintaining measurement redundancy while sharing the digital converter resource. The diagnostic reference input serves as an intermediary test signal to verify ADC functionality.
Solution Approach 2:
The selection circuit provides dynamic routing capability, allowing the system to adaptively switch between different input sources based on measurement needs. This dynamic configuration enables the single ADC to maintain redundancy by selectively processing primary and secondary measurements independently while sharing the same digital conversion resource.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides full redundancy for ASIL D compliance while minimizing die area and current consumption by half, enabling efficient monitoring of large numbers of battery cells.
Implementation Method 1
a first switched capacitor circuit comprising first and second primary input terminals for connecting to respective primary measurement pins of a battery cell, wherein the first switched capacitor circuit is configured to sample a primary cell voltage
Data Source
AI summary
A battery management system comprising: a plurality of analog-to-digital converters, ADCs, each ADC comprising: a first switched capacitor circuit comprising first and second primary input terminals for connecting to respective primary measurement pins of a battery cell, wherein the first switched capacitor circuit is configured to sample a primary cell voltage across the first and second primary input terminals; a second switched capacitor circuit comprising first and second secondary input terminals for connecting to respective cell balancing pins of the battery cell wherein the second switched capacitor circuit is configured to sample a secondary cell voltage across the first and second secondary input terminals; a digital conversion circuit for providing a digital measurement of an input voltage; a diagnostic reference circuit configured to provide a diagnostic reference voltage for testing the function of the digital converter circuit; and a selection circuit configured to selectively connect the digital converter circuit to one or more of: the first switched capacitor circuit, the second switched capacitor circuit and the diagnostic reference circuit.