Photocoupler LED Drive Duty Control for Low-Power Isolation Signaling
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Solution Overview
Problem
Traditional LED drive control circuits for insulation communication in higher-voltage and lower-voltage systems face challenges in reducing power consumption and extending the longevity of light emitting diodes, which are essential for reliable and efficient signal transmission.
Innovation Solution
The proposed LED drive control circuit includes a duty cycle changer that adjusts the duty cycle of the LED drive control signal in synchronization with a reference clock signal, utilizing a clock generator circuit with frequency multiplication and delay circuits to generate an LED driving clock signal with a low duty cycle, minimizing power consumption and reducing the impact of jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LED is continuously lit for signal transmission, then the communication reliability is improved, but the power consumption increases and longevity decreases
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to drive the LED with periodic pulses instead of continuous illumination. The communication signals are transmitted through periodic LED lighting cycles, where the LED is turned on and off at specific intervals to encode data while minimizing overall power consumption and extending LED lifespan.
2Reliability
If the LED drive duty cycle is increased to improve signal transmission quality, then the communication reliability is improved, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the LED drive duty cycle based on communication requirements. The control circuit varies the duty cycle in real-time to match the data transmission needs, using higher duty cycles for critical signals and lower duty cycles for non-critical data, thereby optimizing both transmission quality and power consumption.
Solution Approach 2:
The patent applies parameter changes by modifying the duty cycle parameter of the LED drive signal. The control circuit changes the duty cycle percentage to balance communication reliability and power consumption, adjusting this key parameter based on the specific communication task and system conditions.
3Device complexity
If a simple LED drive circuit is used, then the device complexity is reduced, but the ability to control power consumption and extend LED life is limited
Solution Approach 1:
The patent introduces an intermediary LED drive control circuit between the microcontroller and the LED. This intermediate control layer implements PWM generation and duty cycle adjustment functionality, providing sophisticated power management and LED life extension capabilities without requiring complex integration into the microcontroller itself, thus maintaining relatively simple overall system architecture.
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 efficient power management and prolongs the lifespan of LEDs by optimizing the duty cycle of the LED driving clock signal, thereby reducing power consumption and enhancing the reliability of signal transmission in insulated communication systems.
Implementation Method 1
an isolation amplifier serves to receive and amplify an input signal from a sensing-target device included in a higher-voltage circuit (primary circuitry) and transmits the resultant signal to a lower-voltage circuit (secondary circuitry). The isolation amplifier receives a clock signal from the lower-voltage circuit through a light emitting diode (LED) constituting a photocoupler
Implementation Method 2
a higher-voltage circuit and a lower-voltage circuit are connected through a photocoupling circuit for insulation purpose
Data Source
AI summary
LED drive control circuitry according to one embodiment outputs an LED drive control signal serving as driving a light emitting diode included in a photocoupler that performs insulation communication in synchronization with a reference clock signal. The LED drive control circuit includes a duty cycle changer that changes a duty cycle of the LED drive control signal in accordance with the reference clock signal and a signal synchronized with the reference clock signal.