Sampling Circuit for Transformer Reflected Voltage Measurement
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Solution Overview
Problem
Existing power converter sampling circuits face complexity, imprecision in dynamic loading responses, and limitations due to transformer turn ratio, particularly in discontinuous and continuous current modes.
Innovation Solution
A sampling circuit comprising an amplifier circuit, a capacitor, and a switch, which generates a feedback signal by comparing signals with propagation delay, enabling precise sampling of reflected voltage through a switching signal controlled by a sample-signal circuit, and stopping sampling when the first signal is lower than the second signal or a pulse signal is enabled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple-sampling circuit is used to measure reflected voltage and discharge time, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple sampling operations into a single sampling circuit by using a capacitor to sequentially store voltage values at different time points. The capacitor accumulates charge corresponding to the reflected voltage at specific moments, allowing multiple measurements to be performed without requiring multiple parallel sampling circuits, thus reducing overall circuit complexity while maintaining measurement precision.
Solution Approach 2:
The sampling circuit is designed to perform multiple functions: it measures reflected voltage at different time points, determines discharge time, and provides feedback for power converter control. By making the sampling circuit universal and multi-functional, the patent eliminates the need for separate dedicated circuits for each measurement task, thereby reducing device complexity while preserving comprehensive measurement capabilities.
2Speed
If causal sampling circuit is used to measure reflected voltage and demagnetizing time, then measurement speed is improved, but measurement precision deteriorates under dynamic loading
Solution Approach 1:
The patent uses a capacitor that is pre-charged to a reference voltage level before sampling begins. During the sampling process, the capacitor naturally discharges in response to the reflected voltage, and the discharge time is measured to determine demagnetizing time. This preliminary preparation of the capacitor enables fast causal sampling while maintaining precision because the capacitor's discharge characteristics provide accurate timing information even under dynamic loading conditions.
Solution Approach 2:
The sampling circuit incorporates feedback mechanisms where the measured reflected voltage and discharge time are used to adjust and optimize subsequent sampling operations. The feedback loop ensures that the sampling circuit adapts to dynamic loading conditions, maintaining measurement precision by correcting for variations in real-time while preserving the fast response capability of causal sampling.
3Measurement precision
If linear-predict sampling is used to measure demagnetized voltage, then measurement accuracy is improved, but adaptability to different transformer designs is reduced
Solution Approach 1:
The patent employs a capacitor-based sampling approach where the measurement process relies on voltage discharge characteristics rather than fixed linear prediction models. By changing the measurement parameter from linear prediction to capacitive discharge timing, the circuit becomes adaptable to different transformer designs and turn ratios, as the capacitor's discharge behavior naturally adjusts to the specific transformer characteristics while maintaining measurement accuracy through timing-based detection.
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 provides a simple and precise method for sampling reflected voltage, improving accuracy and adaptability to dynamic conditions in both discontinuous and continuous current modes of power converters.
Implementation Method 1
The first capacitor generates a second signal in response to the reflected voltage
Implementation Method 2
The amplifier circuit is coupled to receive the reflected voltage for generating a first signal
Data Source
AI summary
A sampling circuit of the power converter according to the present invention comprises an amplifier circuit receiving a reflected voltage for generating a first signal. A first switch and a first capacitor are utilized to generate a second signal in response to the reflected voltage. A sample-signal circuit generates a sample signal in response to the disable of a switching signal. The switching signal is generated in accordance with a feedback signal for regulating an output of the power converter. The feedback signal is generated in accordance with the second signal. The sample signal is utilized to control the first switch for sampling the reflected voltage. The sample signal is disabled once the first signal is lower than the second signal. The sampling circuit precisely samples the reflected voltage of the transformer of the power converter for regulating the output of the power converter.