BMC Processing Circuit Dynamic Threshold Adjustment
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Solution Overview
Problem
Existing BMC reception processing techniques, such as those described in US Patent Application Publication No. 2011/0261969, are inadequate for processing USB Power Delivery standard packets due to complexity, increased power consumption, and instability in distinguishing bit rates and signal periods, especially with variations caused by GND level deviations and rising/falling delays.
Innovation Solution
A BMC processing circuit with an edge detection unit, interval measuring unit, threshold determination unit, and BMC decoding unit that dynamically adjusts thresholds based on measured interval values to improve bit distinction accuracy without increasing sampling clock rates, ensuring stable reception processing with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling clock rate is increased to improve bit distinction accuracy, then the accuracy of distinguishing bits is improved, but power consumption increases
Solution Approach 1:
The patent changes the parameter of threshold value dynamically based on measured signal characteristics (high period and low period) rather than using a fixed high sampling clock rate. The threshold determination unit adjusts the threshold parameter according to the actual signal conditions, achieving accurate bit distinction without increasing power consumption from high-speed sampling.
2Reliability
If three types of timing parameters (0.5T, 1T, 1.5T) are used for RATE determination, then synchronization timing can be determined, but the processing becomes complicated
Solution Approach 1:
Instead of determining synchronization timing by comparing received signal widths against multiple predefined timing parameters (0.5T, 1T, 1.5T), the patent inverts the approach by measuring the actual high and low periods of the received signal and directly calculating the threshold based on these measurements. This eliminates the need for complex multi-parameter comparison and determination logic.
3Measurement precision
If two separate circuits (counters) are used to measure high period and low period separately, then bit distinction can be achieved, but the device size and power consumption increase
Solution Approach 1:
The patent merges the measurement of high period and low period into a single integrated measurement process. The interval measuring unit measures both periods simultaneously or in a unified sequence, and the threshold determination unit processes both measurements together to determine the threshold. This combining approach reduces the need for completely separate measurement circuits while maintaining measurement accuracy.
Data Source
AI summary
A BMC processing circuit, a USB power delivery controller, a BMC reception method, and a program capable of achieving stable BMC reception processing with low power consumption are provided. A BMC processing circuit 1100 includes an edge detection unit 1102 that detects change edges of a reception signal encoded by a Biphase Mark Code (BMC) method; an interval measuring unit 1103 that measures an interval value, the interval value being a period between the change edges; a threshold determination unit 1105 that corrects a first threshold using a plurality of interval values to generate a second threshold; and a BMC decoding unit 1107 that decodes the reception signal using the second threshold.