Battery Cell Measurement Circuit for Open Load Detection

The patent divides the measurement function into two separate paths: one for cell balancing measurements and another for open load detection. The OLD detection circuit uses a dedicated measurement path that is independent from the cell balancing pin measurements, allowing both functions to coexist without interference. This segmentation ensures that cell balancing operations do not compromise the accuracy of open load detection.

The patent introduces an intermediary measurement circuit that acts as a mediator between the cell balancing pins and the control system. This intermediary circuit includes precision resistors and measurement channels that isolate the OLD detection from the cell balancing operations, enabling accurate detection while maintaining cell balancing functionality.

The patent designs the measurement circuit to serve multiple functions: it can perform both cell balancing measurements and open load detection using the same physical pins and control circuitry. The measurement channel is configured to switch between different measurement modes, eliminating the need for completely separate dedicated circuits for each function and thereby reducing overall complexity while maintaining redundancy.

The system uses its existing measurement infrastructure to provide self-diagnosis capability. The same control circuit that manages cell balancing also performs open load detection by analyzing voltage measurements during balancing operations. This self-service approach allows the system to monitor its own health without requiring external diagnostic equipment or significantly increasing circuit complexity.