PDN Impedance Detection Using Clock-Modulated Voltage Droop
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Solution Overview
Problem
Existing methods for detecting power delivery network (PDN) degradation in safety-critical systems like automotive vehicle control systems are limited in their ability to identify degradation during booting and mission-mode operation, particularly when compensation methods fail to address voltage droop across a wide frequency range.
Innovation Solution
A method involving modulating a clock signal supplied by the PDN, measuring voltage droop values at varying frequencies, determining impedance values through Fast Fourier Transform (FFT) of these droops, and comparing them against thresholds to detect PDN degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage monitoring methods are used to detect PDN degradation, then the detection process is simple, but the detection precision is insufficient to identify degradation across a wide frequency range
Solution Approach 1:
The patent segments the PDN impedance measurement into multiple frequency points by dividing the frequency range into discrete steps. The testing system measures impedance at each frequency point separately using clock signal modulation at different frequencies, allowing comprehensive frequency range coverage while maintaining manageable system complexity through systematic segmentation of the measurement process
Solution Approach 2:
The patent employs periodic clock signal modulation to stimulate the PDN at different frequencies. By modulating the clock signal periodically at various frequencies and measuring the resulting voltage droop, the system achieves wide frequency range detection capability while using a relatively simple periodic stimulation approach rather than complex continuous analysis
2Adaptability or versatility
If clock signal modulation is used to stimulate voltage droop across a wide frequency range, then the detection capability is improved, but the time required for measurement increases
Solution Approach 1:
The patent performs preliminary characterization of the PDN impedance profile during the design and testing phase, establishing expected impedance values and thresholds across the frequency range. This preliminary action allows the runtime detection system to quickly compare measured values against pre-established benchmarks, reducing the time required for comprehensive frequency range analysis during actual operation
Solution Approach 2:
The patent measures impedance at multiple frequency points across the entire frequency range, potentially measuring more points than strictly necessary for basic detection. This excessive action ensures complete coverage of the frequency range and captures all degradation modes, with the trade-off that measurement time increases but detection comprehensiveness is maximized
3Ease of manufacture
If impedance thresholds are established based on expected use cases, then the detection system is easy to implement, but it fails to detect degradation during booting and mission-mode operation
Solution Approach 1:
The patent creates a universal detection system that functions across multiple operational modes including booting and mission-mode operation. By using clock signal modulation that can be applied regardless of the specific operational state, and by establishing impedance thresholds that cover the full frequency range, the system achieves multi-functional detection capability that works universally across all operational phases
Solution Approach 2:
The patent changes the operational parameters of the detection system to match different operational modes. The clock signal modulation frequency and amplitude are adjusted according to the operational state (booting vs. mission-mode), and impedance thresholds are selected based on the expected impedance profile for each mode, allowing the same detection infrastructure to reliably detect degradation across all operational conditions
Data Source
AI summary
Degradation of a power delivery network (PDN) in a computing device may be detected as part of a self-test during booting of the computing device or a device subsystem. The computing device may be an automotive vehicle control system. A clock signal provided to logic circuitry supplied by the PDN may be modulated, and the modulation frequency may be varied over a range. Voltage droop values in the logic circuitry may be measured in response to the modulation frequencies over the range. Impedance values may be determined by determining an odd harmonic of each of the voltage droop values. The impedance values may be compared with thresholds, and an alert or other indication may be issued if one or more of the impedance values exceeds a threshold.