Photocoupler LED Drive Circuit With Low-Duty Clock Control
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Solution Overview
Problem
Traditional LED drive control circuits for insulation communication in higher- and lower-voltage systems face challenges in reducing power consumption and extending the longevity of light emitting diodes, which are crucial for reliable and efficient signal transmission.
Innovation Solution
The proposed LED drive control circuit incorporates a duty cycle changer and a clock generator circuit that adjusts the duty cycle of the LED drive control signal in synchronization with a reference clock signal, utilizing delay circuits to generate an LED driving clock signal with a low duty cycle, thereby reducing power consumption and minimizing 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 implements periodic LED activation by dividing the signal transmission into discrete time slots synchronized with a clock signal. The LED is activated only during specific periods when data transmission is required, rather than continuously. This is achieved through a shift register that loads data bits sequentially and a control circuit that enables the LED driver only during active transmission cycles, thereby reducing overall power consumption while maintaining communication reliability through structured periodic communication.
Solution Approach 2:
The patent dynamically adjusts the LED driving state based on communication requirements. The system transitions between active (LED on) and inactive (LED off) states according to the data transmission needs. The control circuit monitors the shift register output and dynamically enables/disables the LED driver, creating a dynamic power management system that adapts to communication demands rather than maintaining a static continuous operation mode.
2Reliability
If the LED 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 optimizes the duty cycle parameter of the LED driving signal to achieve the best trade-off between signal transmission quality and power consumption. The control circuit generates a clock signal with a specific duty cycle that provides sufficient light intensity for reliable communication while limiting the average power consumption. By carefully selecting and adjusting the duty cycle parameter, the system achieves adequate signal transmission quality without excessive power consumption.
3Productivity
If the LED drive frequency is increased to improve data transmission rate, then the productivity is improved, but the power consumption increases and longevity decreases
Solution Approach 1:
The patent uses periodic clock signals to control the LED activation timing, where data bits are transmitted in synchronized time slots. The shift register shifts data bits at each clock cycle, and the LED is activated only during the specific time window when a data bit needs to be transmitted. This periodic control structure enables efficient data transmission at optimized frequency rates while minimizing LED on-time and associated power consumption.
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, resulting in reduced power consumption and improved reliability for insulation communication.
Implementation Method 1
an isolation amplifier receives a clock signal from a 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.