Dual Mode Power Supply Controller for Solid-State Lighting
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Solution Overview
Problem
Existing power converter circuits face inefficiencies in regulating current supplied to loads, particularly in solid-state lighting devices, where variations in drive current affect light color and intensity, and existing solutions struggle to accurately control current in hysteretic and critical current modes.
Innovation Solution
A power conversion circuit with a voltage boost configuration that includes a boost inductor, a boost controller, and a control signal generating circuit to regulate output current by controlling the duty cycle of a switched current source, using a balance capacitor and an output current mirror to ensure proportional output current based on input current and voltage signals, and operating in either hysteretic or critical current modes to manage inductor current effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a switched-mode power supply is used to improve efficiency, then energy conversion efficiency is improved, but current regulation precision deteriorates
Solution Approach 1:
The patent implements feedback control by sensing the output current through a sense resistor and comparing it with a reference voltage. The error amplifier continuously adjusts the duty cycle of the switch based on the difference between actual and desired current levels, ensuring precise current regulation while maintaining high efficiency through switched-mode operation.
Solution Approach 2:
The patent replaces mechanical current regulation methods with electronic control mechanisms. Instead of using variable resistors or mechanical switches, the invention uses pulse-width modulation (PWM) controlled by an error amplifier and comparator circuitry to regulate current electronically, achieving both high efficiency and precision.
2Illumination intensity
If the duty cycle is increased to improve light output, then light intensity is improved, but current variation increases
Solution Approach 1:
The error amplifier continuously monitors the output current and adjusts the duty cycle to maintain stable current flow. When current deviates from the reference level, the feedback loop automatically corrects it, ensuring that light intensity can be varied through duty cycle changes without compromising current stability.
Solution Approach 2:
The patent employs dynamic duty cycle adjustment where the control signal varies over time to optimize performance. The duty cycle is dynamically modified based on real-time current conditions, allowing the system to achieve desired light intensity while maintaining current stability through continuous adaptation.
3Device complexity
If a simple control circuit is used to reduce complexity, then device complexity is reduced, but current control accuracy deteriorates
Solution Approach 1:
The patent achieves high current control accuracy with relatively simple circuitry by making each component multi-functional. The error amplifier serves both as a differential amplifier and a PWM modulator, while the comparator acts as both a threshold detector and a control signal generator. This universal approach reduces overall circuit complexity while maintaining precision.
Solution Approach 2:
The patent combines multiple control functions into integrated circuit blocks. The error amplifier integrates differential amplification, voltage comparison, and PWM generation functions. The control circuit merges feedback processing and duty cycle modulation into a single unified structure, reducing component count and complexity while preserving control accuracy.
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
The solution effectively regulates load current, maintaining consistent light output by ensuring the output current is proportional to the input current and voltage, thereby stabilizing light color and intensity in solid-state lighting applications, and improving efficiency by accurately controlling inductor current in various operational modes.
Implementation Method 1
a balance capacitor coupled to the switched current source. A level of the output current is proportional to a product of a level of the analog input current signal and the level of the analog input voltage signal
Implementation Method 2
A switched-mode power supply may include a switch that, when switching on and off, stores energy in an inductor and discharges the stored energy to an output of the switched mode power supply
Data Source
AI summary
A circuit for generating an output current includes a control signal generating circuit that is configured to generate a control signal. The control signal is a function of a level of an analog input voltage signal, and a level of the output current is a function of a level of an analog input current signal and the level of the analog input voltage signal.