Power Supply Frequency Response Testing for Energy Reserve Capacitors
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Solution Overview
Problem
Conventional methods for testing energy reserve systems in automotive safety systems are limited, as they only detect failures during startup and not during operation, and can fail to detect intermittent issues like loose connections due to vibration, leading to potential safety risks.
Innovation Solution
A method involving measuring the frequency response of the RC circuit formed by a series resistor and energy reserve capacitor during system operation, using small test tones injected into the feedback voltage of a DC/DC converter, to determine if the energy reserve capacitor is properly installed and functioning, allowing for continuous monitoring and detection of component validity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ERM testing is performed only during startup, then the testing process is simple and quick, but component failures occurring after startup or intermittent failures due to vibration are not detected
Solution Approach 1:
The patent implements continuous frequency response measurements throughout system operation, not just during startup. The control circuit continuously monitors the RC circuit formed by the energy reserve capacitor and series resistor, enabling detection of intermittent failures and ensuring the capacitor remains functional throughout the entire operational lifecycle.
Solution Approach 2:
The patent uses feedback by measuring the frequency response of the RC circuit and comparing it against expected characteristics. The control circuit receives feedback from continuous measurements and can trigger warnings or shutdowns when deviations indicate capacitor degradation or failure, enabling proactive reliability management.
2Measurement precision
If the test circuit disconnects the energy reserve capacitor during testing, then the measurement can be performed, but connectivity may be lost if the test circuit fails to reconnect
Solution Approach 1:
The patent uses the feedback network and control circuit as intermediaries to perform measurements without complete disconnection. Instead of fully disconnecting the capacitor, the system measures frequency response through the existing feedback path, allowing measurement while maintaining circuit connectivity and enabling immediate reconnection if measurement anomalies occur.
3Reliability
If frequency response measurement is performed during operation using small test tones, then continuous monitoring is enabled, but additional circuitry and measurement complexity are required
Solution Approach 1:
The patent makes the feedback network multi-functional by using it both for its primary voltage regulation function and for frequency response measurements. The same feedback circuitry that controls the DC/DC converter also serves as the measurement path for continuous capacitor verification, eliminating the need for separate dedicated measurement hardware.
Solution Approach 2:
The system performs self-diagnosis by using its own operational feedback network to measure the frequency response of the energy reserve capacitor. The control circuit independently monitors the RC circuit characteristics without requiring external testing equipment, enabling the system to verify its own health continuously.
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
Enables reliable and continuous verification of energy reserve systems, detecting failures and intermittent issues during operation, ensuring the airbag system receives adequate power in emergency situations, thereby enhancing automotive safety compliance with standards like IEC 61508.
Implementation Method 1
measuring a frequency response from a control input of the power supply to the output of the power supply
Data Source
AI summary
In one embodiment, a method of verifying a component coupled to an output of a power supply includes measuring a frequency response from a control input of the power supply to the output of the power supply. The method also includes comparing the frequency response to a predetermined metric based on the measuring. The component is determined to be valid if the frequency response falls within the predetermined metric.