Analog Insulation Multiplexer Circuit for Small-Transformer Stability
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Solution Overview
Problem
Conventional analog insulation multiplexers face issues with magnetic saturation at high temperatures and insufficient response time when using small transformers, leading to incomplete data collection and inadequate settling.
Innovation Solution
An analog insulation multiplexer design incorporating a secondary side output adjusting circuit with a series resistor and capacitor, which adjusts the voltage waveform to maintain a sufficient voltage above the threshold voltage for the FET switch, preventing magnetic saturation and ensuring a wide temperature range operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the transformer is downsized, then the device size is reduced, but magnetic saturation occurs at high temperature and sag increases causing voltage to drop below threshold
Solution Approach 1:
The patent applies parameter changes by modifying the drive pulse waveform parameters (width and amplitude) based on temperature conditions. The control unit adjusts the pulse width and amplitude dynamically - widening and increasing amplitude when temperature is high to prevent magnetic saturation, and narrowing/decreasing when temperature is low to prevent sag-induced voltage drop. This resolves the contradiction by making the transformer size small while maintaining voltage stability through adaptive parameter control.
Solution Approach 2:
The patent implements dynamics by transitioning from a static, fixed pulse width drive method to a dynamic, adaptive pulse width modulation system. The control unit continuously monitors temperature and adjusts the drive pulse characteristics in real-time, creating a dynamic system that adapts to changing thermal conditions. This allows the use of a smaller transformer while maintaining reliable operation across the full temperature range.
2Reliability
If the drive time is shortened to reduce sag, then voltage stability improves, but the pulse width becomes narrower causing insufficient response time and settling
Solution Approach 1:
The patent resolves this contradiction through dynamic pulse width adjustment based on temperature. Rather than using a fixed short pulse width that causes insufficient settling, the system dynamically extends the pulse width when temperature is low (where sag is less severe) to ensure adequate response time and settling. When temperature is high, the pulse width is shortened appropriately. This dynamic adaptation allows voltage stability to be maintained while ensuring sufficient response time under all operating conditions.
Solution Approach 2:
The patent changes the drive pulse parameter (width) as a function of temperature to simultaneously achieve voltage stability and adequate response time. By making the pulse width a variable parameter rather than a fixed value, the system can optimize for voltage stability (shorter pulses to reduce sag) while compensating for response time deficits by extending pulses when needed (at lower temperatures). This parameter change strategy resolves the apparent contradiction between these two requirements.
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 design secures a sufficient period for the secondary side voltage to exceed the threshold voltage, preventing magnetic saturation and allowing for a wide temperature range operation without compromising response time or data collection.
Implementation Method 1
a drive insulation transformer for receiving the drive control signal on a primary side via a first resistor and for delivering an insulated drive control signal from a secondary side
Implementation Method 2
a capacitor having an end connected to a ground and another end connected in series to the second resistor
Implementation Method 3
an analog signal insulation transformer for receiving the chopped analog signal on a primary side and for delivering an insulated chopped analog signal on a secondary side
Data Source
AI summary
An analog insulation multiplexer not causing magnetic saturation even if a small transformer is used and having a wide use temperature range. The analog insulation multiplexer includes: a first switching element for generating a drive control signal in accordance with an external signal; a drive insulation transformer for receiving the drive control signal on a primary side via a first resistor and for delivering an insulated drive control signal from a secondary side; a second switching element for chopping an analog signal input in accordance with the insulated drive control signal; and an analog signal insulation transformer for delivering an insulated chopped analog signal on a secondary side. The analog insulation multiplexer further includes a secondary side output adjusting circuit having a second resistor connected, on the primary side of the drive insulation transformer, in parallel to the first resistor and a capacitor having one end connected to a ground and another end connected in series to the second resistor.