Capacitor Test Circuit for Voltage Regulator EMI Noise Detection
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Solution Overview
Problem
Existing voltage regulator circuits fail to accurately distinguish between noise induced by a missing capacitor and electromagnetic interference (EMI), leading to instability and potential damage to loads due to incorrect detection of component failures.
Innovation Solution
A voltage regulation system with a component test circuit that operates in both normal and open loop modes, using a detection circuit to identify a.c. signals on the output voltage and differentiate between EMI-induced noise and component failures by asserting control signals to determine the presence or absence of a missing capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a peak detector is used to detect missing capacitor by checking for increased a.c. portion of output voltage, then capacitor failure detection is enabled, but the circuit cannot differentiate between EMI disturbances and missing capacitor
Solution Approach 1:
The system performs preliminary action by intentionally disconnecting the capacitor before detection. The control circuit opens the switch to disconnect the capacitor from the output, then activates the detection circuit to measure output voltage characteristics. This preliminary disconnection creates a controlled test condition that enables accurate differentiation between EMI and actual capacitor failures.
Solution Approach 2:
The patent introduces an intermediary detection circuit that measures output voltage characteristics without being directly affected by the capacitor's presence or absence. This intermediary measurement system, combined with control signals that manipulate the capacitor connection state, enables precise detection and differentiation of failure conditions from EMI disturbances.
2Reliability
If periodic pulse is applied to transistor to periodically enable transistor and short resistor value, then capacitor detection is performed, but undesirable variations and overshoot of output voltage occur
Solution Approach 1:
The invention extracts the detection function from the normal voltage regulation operation. Instead of using periodic pulses during normal operation, the system separates detection into a distinct operational mode where the control circuit intentionally disconnects the capacitor and activates detection circuitry. This extraction eliminates the interference between detection activities and voltage regulation, preventing output voltage variations and overshoot.
3Measurement precision
If the capacitor is disconnected to test for failure, then accurate failure detection is possible, but the load loses voltage regulation protection
Solution Approach 1:
The system implements periodic action by cycling the capacitor connection state between connected and disconnected positions under control of a control circuit. During disconnected periods, detection occurs with high accuracy. During connected periods, the capacitor provides voltage regulation protection. This periodic switching enables both accurate detection and continuous protection without permanent loss of either function.
Data Source
AI summary
In one embodiment, a closed loop control system is caused to operate in an open loop configuration. At some time while operating in the open loop configuration the system detected the presence or absence of a.c. signals in an output signal of the system in order to detect the presence or absence of a failure of a control loop element, such as an output capacitor.