LED Drive Circuit Dimming via Dual Sub-Switch Current Control
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Solution Overview
Problem
Existing LED drive circuits with phase-cut dimming functionality are costly due to high material costs, despite meeting performance requirements, and there is a need for a solution that offers effective dimming performance while reducing costs.
Innovation Solution
A drive circuit with a simple structure and low component count, featuring a power supply, boost control unit, main control unit, and load current control unit with a switch unit comprising a first and second sub-switch, where the second sub-switch turns on to maintain current peak and adjust mean current without reducing load voltage, utilizing PWM signals for efficient dimming control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a boost and buck topology pattern is used in the LED drive circuit, then the dimming performance meets design requirements, but the material cost increases resulting in high price illumination device
Solution Approach 1:
The patent extracts and eliminates the buck converter component from the traditional boost-buck topology, using only a boost converter circuit to achieve both voltage boosting and current dimming functions. This simplification reduces material cost while maintaining dimming performance through the switch unit's peak current control mechanism.
Solution Approach 2:
The boost converter circuit is designed to perform multiple functions: voltage boosting for LED operation and current dimming for brightness control. The switch unit integrated into the boost converter handles both voltage regulation and current control, eliminating the need for separate buck converter components and reducing overall circuit complexity and cost.
2Ease of operation
If the second sub switch unit is turned on to maintain current peak, then the mean value of current is adjusted for dimming, but the circuit structure becomes more complex
Solution Approach 1:
The patent merges the dimming control function into the existing boost converter switch unit by adding a second sub switch unit that works in conjunction with the first sub switch unit. This integrated approach combines voltage boosting and current dimming control in a single circuit structure, avoiding the need for separate control circuits and reducing overall system complexity despite the enhanced functionality.
Data Source
AI summary
Various embodiments may relate to a drive circuit of an illumination device. The drive circuit has an output terminal connected to a load of the illumination device. The drive circuit includes a power supply, a boost control unit connected to an output terminal of the power supply, a main control unit connected to the boost control unit, and a load current control unit connected between the main control unit and the load, and including a switch unit. The switch unit includes a first sub switch unit, which is configured to switch according to a dimming control signal from the main control unit, and further includes a second sub switch unit connected to the first sub switch unit. The second sub switch unit is configured to be turned on in a situation where the first sub switch unit is turned on so as to turn off the first sub switch unit.