Switched-Capacitor Load Detection With Fixed Timing
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Solution Overview
Problem
Existing load detection circuits lack a fixed-time detection mechanism, as the detection time is variable and dependent on the load capacitor value, making it unpredictable and unsuitable for applications requiring a predetermined duration.
Innovation Solution
A load detection circuit utilizing a switched capacitor architecture with a digital controller generating fixed period control signals to control a variable current source and switched capacitor circuit, ensuring a fixed detection time independent of the load capacitance value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable gain amplifier and variable current source are used for load detection, then the detection can adapt to different load conditions, but the detection time becomes variable and unpredictable
Solution Approach 1:
The patent uses periodic clock signals to control the switching of capacitors and the operation of the current source, establishing fixed time periods for each detection phase. The digital controller increments counters based on clock cycles, ensuring that each detection stage completes within a predetermined time window, thus making the overall detection time fixed and predictable while maintaining adaptability through digital control.
2Duration of action of moving object
If the detection time is made fixed using digital control, then the detection becomes predictable, but the circuit complexity increases with digital controllers and switched capacitors
Solution Approach 1:
The patent replaces analog timing mechanisms with digital control. Instead of using analog circuits to generate variable time constants, the invention uses a digital controller that counts clock cycles to establish fixed time periods. This substitution of digital for analog control simplifies timing precision while managing circuit complexity through systematic digital logic design.
Solution Approach 2:
The detection circuit is divided into multiple stages, each controlled by switched capacitors that can be independently configured. The digital controller manages each stage separately with fixed time allocations, allowing the complex detection process to be broken down into manageable segments with predictable timing, reducing overall system complexity through modular design.
3Duration of action of moving object
If switched capacitors are used to establish fixed time periods, then the detection time becomes independent of load capacitance, but the circuit architecture becomes more complex
Solution Approach 1:
The patent introduces switched capacitors as intermediary elements between the digital controller and the load detection process. These capacitors are charged and discharged in fixed time periods controlled by clock signals, acting as time-keeping elements that decouple the detection timing from the load capacitance value. The digital controller uses these switched capacitors to establish predetermined time windows for each detection phase.
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
The solution enables a consistent and predictable load detection within less than 300 μs, independent of the load capacitance, enhancing the accuracy and reliability of the detection process.
Implementation Method 1
the current source (107) initially starts to charge the load capacitor CL (113)
Implementation Method 2
a comparator (109)... Once the output voltage Vout reaches a pre-specified value, the counter stops counting
Data Source
AI summary
A load detection circuit includes a variable current source circuit having a first input connected to a power supply, a second input, and a first output connected to an output load; a switched capacitor circuit having a third input connected to an external voltage reference signal, a fourth input connected to the first output of the variable current source, a fifth input connected to ground, a sixth input, and a second output; a comparator having a seventh input connected to the second output of the switched capacitor circuit, an eighth input connected to the first output of the variable current source, and a third output; an edge detector having a ninth input connected to the third output of the comparator, and a fourth output; and a digital controller having a fifth output connected to the variable current source and a sixth output connected to the switched capacitor circuit.