Capacitor Charging Apparatus Tap Voltage Feedback Control
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Solution Overview
Problem
Capacitor charging apparatuses face challenges in accurately detecting output voltage, efficiently adjusting charging current, and optimizing switching transistor timing, leading to inefficiencies and wasteful power consumption due to variations in transformer turns ratio and reliance on high-voltage resistive elements and fixed base or gate current signals.
Innovation Solution
A control circuit that monitors the voltage at a tap on the secondary coil of the transformer to accurately detect output voltage, adjusts the off-time of the switching transistor based on detected voltage, and optimizes the base or gate current of the switching transistor to match the charging current, reducing the number of circuit components and packaging area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If output voltage is monitored directly by dividing it with resistors, then voltage detection is achieved, but high-voltage resistive elements are required which must be installed as chips, resulting in larger packaging area
Solution Approach 1:
The patent introduces an intermediary approach by monitoring the voltage across the primary coil instead of directly measuring the high-voltage output. This intermediary measurement point allows accurate detection of output voltage status without requiring high-voltage rated resistive elements, thereby reducing packaging area while maintaining measurement precision
Solution Approach 2:
The patent creates a correlated signal copy by monitoring the primary coil voltage, which correlates with the output voltage state. This copy signal can be used to infer the output voltage status without directly interfacing with the high-voltage output node, eliminating the need for high-voltage resistors and reducing component count
2Device complexity
If fixed base or gate current signals are used for the switching transistor, then circuit simplicity is maintained, but charging current cannot be efficiently adjusted leading to wasteful power consumption
Solution Approach 1:
The patent implements dynamic control of the switching transistor's base or gate current, allowing the current magnitude to vary according to charging requirements. This dynamic adjustment enables efficient charging current control while maintaining relatively simple circuit architecture, resolving the trade-off between circuit complexity and energy efficiency
Solution Approach 2:
The patent changes the parameter of switching transistor drive current from a fixed value to a variable value that can be adjusted according to charging needs. This parameter change allows the system to optimize power consumption efficiency without significantly increasing circuit complexity, as the adjustment can be achieved through simple control circuitry
3Ease of operation
If switching transistor on and off timing is not optimized, then control simplicity is maintained, but charging efficiency is reduced
Solution Approach 1:
The patent implements feedback control by monitoring the voltage across the primary coil and using this information to optimize the switching transistor's on and off timing. This feedback mechanism enables precise timing control that improves charging efficiency while maintaining operational simplicity, as the control circuit automatically adjusts timing based on real-time voltage conditions
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 solution enables precise output voltage detection and optimal switching control, reducing power wastage, improving charging efficiency, and allowing for compact integration of the control circuit within a single semiconductor substrate.
Implementation Method 1
outputs a boosted input voltage by producing a back electromotive force in the transformer by turning the switching element on and off in a time-division manner
Implementation Method 2
charging an output capacitor with the current flowing through the secondary coil of the transformer
Data Source
AI summary
A capacitor charging apparatus includes a transformer and an output capacitor charged with current flowing through a secondary coil of the transformer, and charges the output capacitor by performing a switching control of a switching transistor provided on a path leading to a primary coil of the transformer. A switching control unit controls on and off of the switching transistor. A voltage detector monitors a voltage at a tap provided in the secondary coil of the transformer. The switching control unit regards the voltage detected by the voltage detector as an output voltage of the capacitor charging apparatus, and controls the on and off of the switching transistor.