Coil Sensor Circuit Switching for Fast DC Offset Cancellation

The patent applies preliminary action by performing DC offset cancellation in advance during a calibration phase before normal operation begins. The system enters a calibration mode where the sensor coil is decoupled and replaced by a DC voltage source, allowing the DC servo-loop to rapidly settle the offset without the constraint of maintaining signal bandwidth. This preliminary offset removal eliminates the trade-off during normal operation, as the offset is already corrected before actual measurement starts.

The patent implements dynamics by making the circuit configuration changeable through a switching mechanism. The system dynamically switches between two modes: calibration mode (with DC voltage source and high gain for fast offset cancellation) and normal operation mode (with sensor coil coupled and appropriate signal bandwidth). This dynamic reconfiguration allows the system to optimize for different requirements at different times, achieving both fast start-up and accurate DC offset cancellation.

The patent applies segmentation by dividing the operation into distinct phases: calibration phase and normal operation phase. During calibration phase, the system uses a DC voltage source instead of the sensor coil, allowing aggressive DC offset cancellation with high gain. During normal operation, the sensor coil is coupled with appropriate bandwidth limitations. This segmentation allows each phase to be optimized independently without compromise.

The patent uses a switching circuit as an intermediary that mediates between the sensor coil and the feedforward amplifier. This switch enables the system to connect different input sources (DC voltage source during calibration, sensor coil during operation) to the amplifier based on the operational phase. The intermediary switch allows seamless transition between calibration and operation modes, enabling fast DC offset cancellation without compromising signal processing during normal use.