Transformerless Hysteretic Boost LED Driver
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Solution Overview
Problem
Conventional LED drivers are complex, heavy, and costly due to the need for additional circuitry to supply varying voltages for LED arrays and auxiliary components, often requiring transformers and auxiliary DC-DC converters.
Innovation Solution
A transformerless hysteretic boost circuit that uses regulated DC voltage from the LED array to power the driver's components, eliminating the need for a transformer and auxiliary DC-DC converter, comprising a self-oscillating circuit driven by a push-pull amplifier and a tap between LEDs for auxiliary power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flyback or boost DC-DC converters are used in LED drivers, then proper DC voltage and current can be provided to the LED load, but the weight, complexity, and cost of the LED driver increases due to additional circuitry for voltage regulation
Solution Approach 1:
The patent extracts and eliminates the transformer and auxiliary DC-DC converter from the LED driver circuitry. By using a capacitor-driven voltage multiplication circuit, the design removes these heavy and complex components while still providing the necessary high voltage for LED operation, directly reducing device complexity and weight
Solution Approach 2:
The LED array itself serves as the power source for the driver circuitry through voltage tapping. The high-voltage LED array provides feedback voltage that is rectified and regulated to generate the auxiliary DC voltages needed for controlling the driver, eliminating the need for separate auxiliary power conversion circuitry
2Reliability
If transformers and auxiliary DC-DC converters are included in the LED driver, then voltage regulation for LED array and auxiliary components is achieved, but the weight of the LED driver increases
Solution Approach 1:
The patent removes the transformer from the circuit by using a capacitor-based voltage multiplication approach. The capacitors charge during the switching cycle and discharge to provide the high voltage needed for LED operation, eliminating the heavy transformer component while maintaining voltage regulation capability
Solution Approach 2:
The patent replaces the magnetic field-based transformer with an electric field-based capacitor voltage multiplication system. This substitution eliminates the heavy magnetic core and windings, significantly reducing the weight of the LED driver while achieving the same voltage transformation function
3Adaptability or versatility
If additional circuitry is added to supply varying voltages for LED array and auxiliary components, then proper voltage distribution is achieved, but the cost of the LED driver increases
Solution Approach 1:
The LED array serves multiple functions: it is both the load that consumes power and the power source that generates auxiliary voltages for the driver circuitry. By tapping voltage from the LED array and rectifying it, the system generates the necessary DC voltages for controlling the driver, making the LED array a multi-functional component that reduces the need for separate power conversion circuits
Solution Approach 2:
The patent combines the power delivery function and the auxiliary power generation function into a single integrated circuit architecture. The same switching circuitry and capacitors used to drive the LED array also generate the auxiliary voltages through voltage multiplication and rectification, reducing the total component count and manufacturing cost
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 weight, complexity, and cost of the LED driver while providing proper voltages, achieving high power density by deriving power from the LED array itself, eliminating the need for conventional transformers and DC-DC converters.
Implementation Method 1
a capacitor coupled in series with the LED array and configured to charge during the switch on-time and discharge during the switch off-time
Implementation Method 2
a diode coupled in series with the capacitor and configured to block current flow during the switch on-time
Data Source
AI summary
A system and apparatus including a light emitting diode (LED) driver provides an operating DC voltage to a plurality of LEDs connected in series (LED array) for providing illumination. A rectifier circuit and a filter are coupled to an AC power supply and provide a rectified and filtered DC source voltage to a transformerless voltage boost circuit, which provides the operating DC voltage to the LED array. A hysteretic self-oscillating circuit drives the transformerless voltage boost circuit at an oscillation frequency. A tap is connected between two LEDs in the LED array, which provides an auxiliary DC voltage, which is used to power the oscillating circuit and which eliminates the need for the LED driver to have a conventional transformer or auxiliary DC-DC power converter. The transformerless voltage boost circuit includes an inductor, a capacitor, a diode, and a switch wherein the switch is controlled by the oscillating circuit.