Receiver Sampling Timing Calibration Against DC-DC Converter Noise
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Solution Overview
Problem
The co-location of DC-DC converters, transmitter elements, and receiver paths in applications like NFC and RFID readers results in significant noise interference due to the disparity in transmit and receive signal strengths, affecting receiver performance.
Innovation Solution
A controller is employed to perform a calibration process that measures noise in the receiver path for different candidate offset settings of the switching and sampling schedules, selecting the setting that minimizes noise interference by adjusting the timing of the DC-DC converter and receiver path operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DC-DC converter, transmitter element and receiver path are co-located on the same die, then device integration and compactness are improved, but noise interference in the receiver path increases due to the large transmit power and switching operations
Solution Approach 1:
The patent applies dynamics by making the timing relationship between DC-DC converter switching and receiver path sampling adjustable through offset calibration. The system dynamically optimizes the relative timing by applying time offsets to synchronize or desynchronize operations based on measured noise levels, thereby reducing noise interference while maintaining co-location benefits
Solution Approach 2:
The patent changes the timing parameter by introducing adjustable time offsets between the switching schedule of the DC-DC converter and the sampling schedule of the receiver path. By calibrating these offsets and selecting optimal values, the system modifies the temporal relationship between noisy switching events and sensitive sampling operations to minimize noise coupling
2Power
If transmit power is increased for NFC/RFID applications, then communication range and reliability are improved, but noise interference in the co-located receiver path increases due to the disparity in signal strengths
Solution Approach 1:
The patent addresses the power disparity problem by introducing a temporal dimension to the solution. Instead of trying to balance power levels directly, the system uses time offset calibration to separate the high-power transmit operations from the sensitive receive sampling operations in the time domain, effectively managing the noise interference caused by large transmit power
3Ease of operation
If DC-DC converter switching schedule and receiver path sampling schedule are synchronized with default timing, then device operation simplicity is maintained, but receiver performance deteriorates due to noise from switching events occurring during sampling periods
Solution Approach 1:
The patent applies preliminary action by performing noise calibration and offset selection during device initialization or setup phase. The optimal time offsets are determined in advance through measurement and stored for use during normal operation, allowing the system to maintain both simplicity and performance without requiring real-time adjustments during operation
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
This approach effectively reduces noise interference, ensuring optimal receiver performance by dynamically optimizing the timing of the DC-DC converter and receiver path operations, thus improving signal-to-noise ratio (SNR) and receiver sensitivity.
Implementation Method 1
a transmitter element configured to generate one or both of a magnetic field or electromagnetic signal
Data Source
AI summary
An apparatus includes a transmitter; a DC-DC converter configured to generate, based on a switching schedule, an output voltage for the transmitter element; a receiver path to sample a received signal based on a sampling schedule; a noise detector to measure receiver path noise; and a controller to perform a calibration process. The calibration process includes acquiring a first measurement of receiver path noise for a first candidate offset setting that defines a first time offset applied to default timing of one of the switching schedule and the sampling schedule; acquiring a second measurement of receiver path noise for a second candidate offset setting that defines a second, different, time offset applied to default timing of the switching schedule and the sampling schedule; and selecting for use in sampling the received signal, one of the first or second candidate offset setting based on a noise-based criteria.