Switching Power Supply Controller for Phase-Cut Dimmer Light Control
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Solution Overview
Problem
Single stage switching power supply solid state light drivers face challenges in precise control of light output when used with phase-cut dimmers, as they lack the decoupling and optimization capabilities of dual stage systems, leading to difficulties in maintaining stable and sensitive brightness control, especially at low brightness levels.
Innovation Solution
A switching power supply controller that senses input signals from phase-cut dimmers and generates switch signals with specific subsets of switching cycles to control energy transfer to solid state lighting elements, allowing for precise energy management and consistent sensitivity across brightness settings, even in single stage configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single stage switching power supply is used to reduce device complexity and cost, then manufacturing precision and control of light output become difficult
Solution Approach 1:
The patent segments the switching cycles into two distinct subsets: a first subset for normal operation and a second subset for fine-grained energy transfer control. This segmentation enables precise control of light output by selectively adjusting the number and characteristics of switching cycles in each subset, resolving the contradiction between simple single-stage architecture and precise light control requirements
Solution Approach 2:
The controller dynamically adjusts the number of switching cycles in the second subset based on the desired light output level. By making the switching cycle count variable rather than fixed, the system achieves fine-grained control over energy transfer to the LED, enabling precise brightness control without requiring complex dual-stage architecture
2Measurement precision
If the number of switching cycles is reduced to achieve fine-grained energy control, then control precision improves, but stability of light output deteriorates
Solution Approach 1:
By dividing switching cycles into two subsets with different control characteristics, the patent achieves both fine-grained energy control and stable light output. The first subset provides stable baseline operation while the second subset enables precise incremental control, resolving the contradiction between control precision and output stability
Solution Approach 2:
The patent changes the parameter of switching cycle characteristics by creating two distinct subsets with different control strategies. This parameter differentiation allows the system to achieve both precise energy transfer (through controlled reduction in second subset) and stable light output (through coordinated operation of both subsets)
3Measurement precision
If a burst period less than conduction period is used to improve energy transfer control, then sensitivity of brightness control becomes constant, but complexity of control logic increases
Solution Approach 1:
The patent segments control logic into distinct phases corresponding to the two subsets of switching cycles. This structured segmentation of control logic makes the complexity manageable by organizing it into repeatable patterns rather than monolithic complex algorithms, enabling constant sensitivity brightness control
Data Source
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AI summary
A switching power supply controller, the controller configured to generate a switch signal for controlling a switch to convert an input signal from a phase cut dimmer into a driving signal for a solid state lighting element, wherein the controller is configured to determine a conduction period of the input signal from the phase cut dimmer within a half cycle period of the input signal, determine a burst period within said conduction period comprising a period of time less than said conduction period, and generate a switch signal comprising a plurality of switching cycles over the burst period, the switch signal comprising a first subset of switching cycles and a second subset of switching cycles, wherein the controller is configured to control the switching cycles of the second subset such that the average energy transferred per switching cycle to the driving signal is less than the average energy transferred per switching cycle to the driving signal for the switching cycles of the first subset.