Signal Transmission Circuit Noise Immunity via Pulse Width Differentiation
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Solution Overview
Problem
In signal transmission circuits with insulated transmission and reception apparatuses, noise interference can lead to incorrect detection of urgent abnormality information, as existing configurations do not effectively differentiate between temperature and abnormality signals, particularly when both are transmitted via a common insulation element.
Innovation Solution
The implementation of a signal transmission circuit that uses separate transmission units for temperature and abnormality information, where the abnormality information is transmitted with a longer wavelength pulse to distinguish it from temperature information, even when noise is present, ensuring accurate detection by the reception apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a common insulation element is used to transmit both temperature information and abnormality information, then the number of insulation elements is reduced, but noise interference causes incorrect detection of abnormality information
Solution Approach 1:
The patent applies parameter changes by modifying the pulse width (duration) of abnormality information pulses to be longer than temperature information pulses. This parameter differentiation allows the reception apparatus to distinguish between the two types of information based on pulse duration, enabling accurate detection of abnormality information even when transmitted through a common insulation element alongside temperature information.
2Reliability
If abnormality information is transmitted with a shorter time ratio (duty cycle) to indicate higher urgency, then the urgency is conveyed, but noise makes the information harder to detect accurately
Solution Approach 1:
The patent resolves this contradiction by changing the pulse width parameter rather than relying solely on duty cycle. Abnormality information is transmitted using pulses with a longer duration (wavelength) than temperature information pulses. This longer pulse width provides a distinct temporal signature that enables accurate detection even with noise present, while still maintaining the ability to convey urgency through the information content.
3Device complexity
If the reception apparatus uses a simple configuration without wavelength detection components, then the device complexity is reduced, but it cannot distinguish between temperature and abnormality information
Solution Approach 1:
The patent enables simple reception apparatus to differentiate between information types by encoding the distinction in the pulse width parameter. The reception apparatus only needs to measure pulse duration to determine whether the signal represents temperature information or abnormality information, eliminating the need for complex wavelength detection components while preserving full information differentiation capability.
Data Source
AI summary
In a signal transmission circuit including a drive circuit and a control apparatus which are insulated from each other and between which a signal indicative of predetermined information is transmitted via a magnetic coupler, the drive circuit includes a temperature information transmission unit transmitting a first signal indicative of temperature information based on the number of pulses consecutively output with a predetermined period and each having a first waveform with a duty cycle of less than 100% with respect to the period and an abnormality information transmission unit transmitting a second signal indicative of abnormality information based on a pulse having a longer wavelength than the first waveform. The temperature information transmission unit transmits the first signal to the control apparatus and the abnormality information transmission unit transmits the second signal to the control apparatus, via the magnetic coupler common to two information transmission units.