LED Driver Circuit Using Regenerative Control
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Solution Overview
Problem
Existing LED driver circuits are complex, costly, and burdened by microprocessor data processing, leading to potential delays in output signals and inadequate current measurement, resulting in undesired current deviations and inefficiencies in LED illumination.
Innovation Solution
A low component count regenerative circuit with a series connection of LED illumination devices, an inductor, and a current measurement element, utilizing a comparator to control the switch and eliminate the need for a microprocessor, allowing precise current measurement and control, and incorporating parallel switches for independent intensity control of LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a microprocessor is used to control the switching and provide delay functionality, then the circuit can achieve LED dimming control, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and removes the microprocessor from the circuit, replacing it with a simplified regenerative circuit using basic electronic components (comparator, transistor, resistor, capacitor) to achieve the same dimming control function with much lower complexity
Solution Approach 2:
The regenerative circuit automatically generates the required delay and switching control signals through its own oscillation mechanism, eliminating the need for external microprocessor control and data processing
2Ease of operation
If a microprocessor is used to provide delay and switching control, then LED intensity can be regulated, but data processing burden increases and may cause output signal delays
Solution Approach 1:
The patent replaces the electronic data processing system (microprocessor) with an analog regenerative circuit that naturally produces timing signals through physical oscillation, eliminating data processing burden entirely
3Measurement precision
If a resistor is used to measure current through LEDs, then current can be monitored, but measurement is inadequate when the transistor is non-conducting
Solution Approach 1:
The patent introduces a dedicated current sensing resistor positioned in the freewheeling path that specifically measures the inductor current during the transistor's non-conducting phase, providing complementary measurement information that the main current resistor cannot capture
4Ease of operation
If conventional pulse width modulated switchers are used, then LED current can be controlled, but component count and cost increase
Solution Approach 1:
The patent merges the current sensing function, timing function, and switching control function into a single integrated regenerative circuit block, eliminating the need for separate PWM controller, timing circuits, and current sensing electronics
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 solution reduces component count and cost, achieves high switching frequencies with low ripple, enabling effective operation near maximum allowable currents, and avoids flickering at low intensities, while providing precise control and reduced electromagnetic emission.
Implementation Method 1
an inductor, in a series connection with the switch, the switch to in a closed (i.e. substantially conductive) state thereof charge the inductor and in an open (substantially non-conductive) state thereof allow the inductor to discharge
Implementation Method 2
a comparator to compare a signal representing the current measured by the current measurement element with a reference, an output(signal) of the comparator being provided to a driving input of the switch
Data Source
Figure 1~2
Figure 3
AI summary
A circuit for driving a LED assembly comprises at least one LED illumination device. The circuit comprises: - a switch, - an inductor, in a series connection with the switch, the switch to in a closed state thereof charge the inductor and in an open state thereof allow the inductor to discharge, - a current measurement element to measure a current flowing through at least one of the inductor and the LED illumination device in the open and closed state of the switch. The switch, inductor and current measurement element are arranged to establish in operation a series connection with the LED illumination device. The circuit further comprises a comparator to compare a signal representing the current measured by the current measurement element with a reference. An output of the comparator is provided to a driving input of the switch for driving the switch from one of an open and a closed state of the switch to the other one of the open and the closed state of the switch upon a change of an output state of the output of the comparator.