LED Driver Circuit Using Peak Current Sensing and VCO Control
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Solution Overview
Problem
The high cost per lumen of LED lighting solutions is hindered by the need for drive circuitry and power supplies, making them less adoptable despite their efficiency and long lifespan compared to incandescent and fluorescent lamps.
Innovation Solution
An electronic circuit comprising a logic drive circuit, voltage controlled oscillator, power switch, and current sensors is used to efficiently power LED lamps, including a transformer and phototransistor for opto-isolation, which dynamically controls the power switch based on peak current sensing and reference voltage comparison to optimize power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED lamps are used to replace incandescent and fluorescent lamps, then energy efficiency and lifespan are improved, but cost per lumen remains high due to drive circuitry and power supply requirements
Solution Approach 1:
The patent combines the drive circuitry and power supply functions into a single integrated circuit that controls the LED lamp. The integrated circuit includes a voltage-controlled oscillator, logic drive circuit, power switch, and current sensors all working together as one unified device, eliminating the need for separate complex power supply units and reducing overall system complexity while maintaining LED efficiency
Solution Approach 2:
The integrated circuit performs multiple functions: it generates timing signals from the voltage-controlled oscillator, controls the power switch switching, monitors current through sensors, and regulates power delivery to the LED lamp. This multi-functional design replaces what would traditionally require separate dedicated circuits for each function, reducing cost per lumen while preserving energy efficiency
2Productivity
If the power switch is dynamically controlled based on peak current sensing, then power delivery efficiency is optimized, but device complexity increases
Solution Approach 1:
The patent employs current sensors that continuously monitor the current flowing through the LED lamp and provide feedback to the logic drive circuit. Based on this feedback, the logic drive circuit dynamically adjusts the power switch timing and duty cycle to optimize power delivery. The voltage-controlled oscillator adjusts its frequency in response to current conditions, creating a closed-loop control system that maximizes LED performance while managing complexity through intelligent regulation
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 the average power current and cost per lumen by dynamically controlling the power switch, ensuring efficient and cost-effective LED lamp operation while maintaining a stable power supply to the LED lamp.
Implementation Method 1
The voltage controlled oscillator is coupled to receive a first reference voltage and coupled to provide a first logic control signal to the logic drive circuit
Implementation Method 2
The transformer comprises a primary winding and a secondary winding. The primary winding has a first terminal coupled to a power source and a second terminal coupled to the first terminal of the power switch. The secondary winding having a first terminal and second terminal coupled to provide the power current to the LED lamp
Implementation Method 3
The first current sensor is coupled to sense a peak current passing through the power switch and coupled to provide a second logic control signal to the logic drive circuit
Implementation Method 4
a power switch and a first current sensor... delivering the power current to the LED lamp
Data Source
AI summary
In one embodiment, the present invention includes an electronic circuit for providing a power current to an LED lamp. The electronic circuit comprises a logic drive circuit, a VCO, a power switch, and a first current sensor. The VCO is coupled to provide a first logic control signal to the logic drive circuit. The power switch has a first terminal and second terminal coupled to deliver the power current to the LED lamp and a control terminal coupled to receive a power control signal from the logic drive circuit. The first current sensor is coupled to sense a peak current passing through the power switch and coupled to provide a second logic control signal to the logic drive circuit.