Complementary Optocoupler Isolation Circuit for Fast Pulse Transmission
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Solution Overview
Problem
Existing signal isolation and conversion circuits face issues with transmission delay, signal distortion, light attenuation, and temperature drift, especially in high-speed applications, and are costly due to the limitations of optical isolation technology.
Innovation Solution
A signal isolation and conversion circuit comprising a pulse signal generating circuit and an optical coupling complementary isolation circuit with at least two photocouplers, which are turned on or off to transmit pulse signals, along with additional components like current and voltage limiting circuits and pulse width shaping circuits to improve signal quality and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed optocoupler is used to achieve fast transmission speed (1 MHz), then transmission speed is improved, but cost increases more than ten times compared to ordinary optocoupler
Solution Approach 1:
The patent divides the signal transmission function into two separate channels: a first optocoupler for transmitting high-level signals and a second optocoupler for transmitting low-level signals. This segmentation allows the use of low-cost ordinary optocouplers instead of expensive high-speed optocouplers, while still achieving fast response through complementary switching action.
Solution Approach 2:
The patent uses periodic pulse width modulation (PWM) signals to drive the complementary optocoupler system. By switching between the first and second optocouplers in periodic alternation based on the PWM signal, the system achieves high-speed transmission capability using inexpensive components.
2Ease of manufacture
If low-speed optocoupler is used to reduce cost, then cost is reduced, but transmission delay and signal distortion occur due to turn-off trailing current
Solution Approach 1:
The patent inverts the conventional single optocoupler approach by using two optocouplers in a complementary configuration. When one optocoupler is turning off, the other turns on, effectively canceling out the trailing current delay effect and eliminating transmission delay while maintaining low cost.
Solution Approach 2:
The complementary connection between the first and second optocouplers creates a feedback mechanism where the state of one optocoupler directly influences the other. This feedback arrangement ensures that trailing current from one device is compensated by the complementary action of the other, eliminating signal distortion.
3Device complexity
If single optocoupler is used for isolation, then device complexity is reduced, but temperature drift and light attenuation occur affecting long-term stability
Solution Approach 1:
The patent segments the isolation function into two parallel optocoupler channels. By distributing the transmission task across two devices, the system compensates for individual device degradation from temperature drift and light attenuation, maintaining overall signal integrity and long-term reliability.
Solution Approach 2:
The patent changes the operational parameters by using complementary switching between two optocouplers. This parameter change allows the system to maintain consistent transmission characteristics over time and temperature, as the complementary action compensates for parameter drift in individual devices.
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 effectively addresses transmission delay, signal distortion, and light attenuation issues while maintaining consistent performance over long service life and reducing costs by using complementary photocouplers to enhance signal timeliness and stability.
Implementation Method 1
The optical coupling complementary isolation circuit comprises at least two photocouplers, and the at least two photocouplers are turned on or turned off according to the pulse signal so as to transmit the pulse signal
Data Source
AI summary
The invention relates to a signal isolation and conversion circuit and a control apparatus. The signal isolation and conversion circuit comprises a pulse signal generating circuit and an optical coupling complementary isolation circuit connected with the pulse signal generating circuit; the pulse signal generating circuit is used for receiving an input signal and converting the input signal into a pulse signal; the optical coupling complementary isolation circuit comprises at least two photocouplers, and the at least two photocouplers are switched on or off according to the pulse signal so as to transmit the pulse signal to the output end of the signal isolation and conversion circuit. By arranging the optical coupling complementary isolation circuit, the problems of transmission delay, transmission signal distortion and light attenuation and temperature drift of the light-emitting diode in the optocoupler are effectively solved, the timeliness of isolation signal transmission is improved.