Transformer Sample-and-Hold Circuit With Adaptive Sampling Delay
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Solution Overview
Problem
Existing sample-and-hold circuits for transformers use a fixed sampling time, which can lead to poor stabilization of output voltage and incorrect sampling of auxiliary winding voltage due to varying discharge times with different loads, especially under light loads.
Innovation Solution
A sample-and-hold circuit with a discharge detection unit and a sample delay time generation unit that generates variable sample delay times based on discharge times, using different reference currents to adjust the sampling time according to the load, ensuring accurate voltage sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed sampling time is used in the sample-and-hold circuit, then the circuit structure is simple, but the output voltage stabilization is poor and sampling accuracy deteriorates under varying load conditions
Solution Approach 1:
The patent applies the dynamics principle by making the sampling time variable rather than fixed. The sample-and-hold circuit dynamically adjusts the sampling time based on the actual discharge time of the transformer, which varies with load conditions. This is achieved through a control circuit that detects the discharge time and correspondingly adjusts the sampling time, ensuring accurate sampling regardless of load variations.
Solution Approach 2:
The patent applies the parameter changes principle by changing the sampling time parameter according to the discharge time parameter. When the discharge time changes due to different load conditions, the sampling time parameter is adjusted accordingly. This parameter adaptation ensures that the sampling operation always occurs at the appropriate moment in the transformer cycle, maintaining measurement precision across varying operating conditions.
2Ease of operation
If a fixed sampling time is used in the sample-and-hold circuit, then the circuit operation is simple, but the output voltage stabilization deteriorates under varying load conditions
Solution Approach 1:
The patent applies the feedback principle by implementing a control circuit that monitors the discharge time of the transformer and uses this information to adjust the sampling time. The feedback mechanism ensures that the sampling operation is synchronized with the actual discharge characteristics, which stabilizes the output voltage by ensuring accurate voltage sampling regardless of load variations.
Solution Approach 2:
The patent applies the dynamics principle by making the sampling time adaptive rather than static. The circuit dynamically responds to changes in discharge time by adjusting the sampling timing accordingly. This dynamic adjustment maintains proper sampling synchronization under varying load conditions, thereby stabilizing the output voltage.
3Measurement precision
If a variable sample delay time is generated based on discharge time, then sampling accuracy is improved under varying load conditions, but the device complexity increases
Solution Approach 1:
The patent applies the universality principle by designing a control circuit that performs multiple functions: detecting the discharge time, determining the appropriate sampling time based on the detected discharge time, and generating the sampling control signal. This multi-functional approach improves sampling accuracy while minimizing the increase in device complexity by consolidating functions into a single integrated control unit.
Data Source
AI summary
A sample-and-hold circuit for generating a variable sample delay time of a transformer includes a discharge detection unit, a sample delay time generation unit, and a comparator. The discharge detection unit generates a first voltage according to a first turning-on signal and a first reference current. Length of the first turning-on signal is varied with a discharge time of a present period of the transformer. The sample delay time generation unit generates a second voltage according to the first turning-on signal and a second reference current. The comparator generates a sample signal to a control circuit of the transformer according to a first voltage corresponding to a previous period of the transformer and a second voltage corresponding to the present period of the transformer. The first reference current is K times the second reference current, and 0<K<1.