Impedance Measurement With Coupling Capacitor Precharging
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Solution Overview
Problem
Existing impedance measuring devices face challenges in accurately measuring internal impedance due to disconnection issues, particularly when contact terminals are not in contact or removed during measurement, leading to longer detection times and inefficiencies in charging coupling capacitors.
Innovation Solution
Incorporating a charging acceleration unit that uses hysteresis comparators to quickly charge coupling capacitors when the voltage between terminals exceeds a prescribed range, allowing for rapid disconnection detection by ensuring the current source operates within its compliance voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capacitance of coupling capacitors is increased to reduce capacitive impedance, then the impedance measurement accuracy is improved, but the charging time of the capacitors increases
Solution Approach 1:
The charging acceleration unit performs preliminary charging of the coupling capacitor before disconnection detection is needed. By detecting when the voltage exceeds the compliance voltage range and initiating charging in advance, the system ensures the capacitor is ready for immediate disconnection detection without delaying the measurement process.
Solution Approach 2:
The charging acceleration unit operates periodically to monitor and charge the coupling capacitor as needed. It detects voltage conditions and initiates charging only when necessary, creating a periodic check-and-charge cycle that maintains readiness without continuous operation, thus reducing overall time loss.
2Reliability
If the capacitance of coupling capacitors is increased to reduce capacitive impedance, then the current source for disconnection detection can function normally, but the response time of disconnection detection increases
Solution Approach 1:
The charging acceleration unit performs preliminary charging of the coupling capacitor before disconnection detection is needed. By detecting when the voltage exceeds the compliance voltage range and initiating charging in advance, the system ensures the capacitor is ready for immediate disconnection detection without delaying the measurement process.
Solution Approach 2:
The charging acceleration unit automatically monitors the voltage across the coupling capacitor and initiates charging when needed, without requiring external intervention. This self-service mechanism ensures the system maintains optimal operating conditions autonomously, improving reliability while minimizing response time delays.
3Reliability
If the voltage between terminals exceeds the compliance voltage range, then the current source for disconnection detection cannot supply normal current, but increasing capacitance to handle voltage takes more charging time
Solution Approach 1:
The charging acceleration unit continuously monitors the voltage across the coupling capacitor and uses this feedback to determine when charging is needed. When the voltage exceeds the compliance voltage range, the unit activates to charge the capacitor, and stops when the voltage returns to the acceptable range, creating an efficient feedback-controlled charging system.
Solution Approach 2:
The system changes the operating parameters of the charging acceleration unit based on the voltage conditions. It activates charging only when the voltage exceeds the compliance range and deactivates when within range, dynamically adjusting its operation to match the actual needs of the circuit, thus minimizing unnecessary charging time.
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 enables rapid charging and disconnection detection, reducing overall measurement time by preventing restarts during voltage fluctuations and ensuring accurate impedance measurements.
Implementation Method 1
coupling capacitors are respectively inserted between a measurement target object and a current source for measurement, between the measurement target object and a measurement unit, and between the measurement target object and a current source for disconnection detection
Implementation Method 2
the charging acceleration unit has hysteresis characteristics. It becomes possible to prevent the charging acceleration unit from restarting due to voltage fluctuations caused by the alternating current for disconnection detection
Data Source
AI summary
To provide an impedance measuring device that allows charging of a coupling capacitor and detection of disconnection in a short time.The above object can be accomplished by an impedance measuring device (200) including: a measurement unit (200) that measures a voltage, generated between contact terminals that respectively contact both terminals of a measurement target object (230) by an alternating current supplied to the measurement target object (230), and determines an internal impedance of the measurement target object (23); a current source for disconnection detection (241) that supplies an alternating current for disconnection detection to a current path (201) between the measurement unit (220) and the measurement target object (230) via a coupling capacitor (C3); and a charging acceleration unit (242) connected between the coupling capacitor (3) and the current source for disconnection detection (241) to charge the coupling capacitor (C3) when the voltage between both the terminals of the current source for disconnection detection (241) exceeds a prescribed voltage range.