Insulated Analog Multiplexer Pulse Timing to Prevent Transformer Noise
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Solution Overview
Problem
Conventional analog multiplexers with insulated power supplies suffer from noise interference due to magnetic field coupling between transformers, making it difficult to collect analog data with high precision, especially in high-density arrangements, and require costly shielding to mitigate this issue.
Innovation Solution
The design incorporates a continuous pulse generation circuit, an inhibit generation circuit, and an AND gate to generate a pulse train that drives the power supply transformer independently of the analog signal transformer, preventing overlapping of drive and power supply pulses and reducing noise induction, allowing for high-precision data collection without the need for shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transformers are arranged in high-density configuration to reduce device size, then device compactness is improved, but magnetic field coupling between transformers increases causing noise interference
Solution Approach 1:
The patent applies periodic action by generating pulse trains with specific timing relationships. The drive pulse train and power supply pulse train are generated periodically but with different duty cycles and timing, ensuring they do not overlap. This periodic but staggered activation reduces magnetic field coupling noise while maintaining high-density transformer arrangement.
Solution Approach 2:
The patent implements dynamics by making the duty cycles of drive and power supply pulse trains adjustable and independent. The control circuit can dynamically adjust the timing and width of pulses to optimize performance and minimize interference based on operating conditions, rather than using fixed pulse parameters.
2Object-affected harmful factors
If shielding is added to prevent magnetic field coupling between transformers, then noise interference is reduced, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/physical shielding approach with an electrical/control-based solution. Instead of adding physical barriers between transformers, the invention uses synchronized pulse generation and timing control to inherently prevent noise interference, eliminating the need for complex shielding structures.
Solution Approach 2:
The patent converts the potential harmful effect of close transformer proximity into a benefit by using the controlled pulse timing to ensure that when one transformer is active, the other is inactive. This transforms what would normally be a source of interference into a mechanism for reducing overall system complexity.
3Device complexity
If drive pulse and power supply pulse overlap in time, then circuit operation is simplified, but noise is induced due to simultaneous transformer activation
Solution Approach 1:
The patent applies segmentation by dividing the pulse generation into separate, independently controllable pulse trains. The drive pulse train and power supply pulse train are generated separately with different timing characteristics, ensuring they do not overlap. This segmentation prevents noise while maintaining relatively simple circuit operation.
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 accurate and noise-free analog data collection even in high-density configurations, eliminating the requirement for costly shielding and enhancing precision by avoiding magnetic field coupling between transformers.
Implementation Method 1
a magnetic field is generated by the power supply transformer T1 in response to the continuous pulse to be driven, whereby the power supply transformer T1 is coupled with the analog signal transformer T2
Data Source
Figure 1
Figure 2(a)~2(g)
Figure 3
AI summary
Provided is an analog multiplexer with an insulated power supply which does not require a shield surrounding the entire transformers, and is capable of easily collecting analog data with high precision even in the case of high-density arrangement/wiring. The analog multiplexer with an insulated power supply includes: an analog signal transformer for receiving an input of an analog signal in a primary winding thereof via an FET, and performing ON/OFF driving on the FET to generate a pulse with an amplitude of the analog signal in a secondary winding thereof; a drive transformer for receiving an input of a drive pulse in a primary winding thereof via an FET to generate a pulse for turning ON/OFF the FET in a secondary winding thereof; an inhibit generation circuit for generating an inhibit pulse having a pulse width wider than a pulse width of the drive pulse; an AND gate for determining a logical product of a continuous pulse sent from a continuous pulse generation circuit and the inhibit pulse to obtain a power supply pulse train; and a rectifying/smoothing circuit for obtaining a direct current voltage corresponding to the power supply pulse train to apply the direct current voltage to the primary winding of the transformer through high resistance.