LED Driver Circuit Using Inductive Current Control
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Solution Overview
Problem
Existing LED driving circuits are complex and costly due to the need for additional components like current comparators to regulate voltage, especially when dealing with AC sources, and there is a need for a simpler, low-cost solution that can maintain a constant current through LED loads.
Innovation Solution
A method and circuit that utilize an inductive element and a connection control element to control the flow of current through an LED load by adjusting the ON and OFF states of a switch, allowing for a predetermined average current to be maintained without the need for current measurement, using a microcontroller to manage the switch's operation based on input and output voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a buck-boost topology with additional switches and diodes is used to regulate voltage, then the LED driver can handle both voltage boosting and decreasing, but the circuit complexity and manufacturing cost increase
Solution Approach 1:
The patent applies a single buck converter topology that can operate in different modes to achieve both voltage boosting and decreasing functions. The converter uses one switch and one diode but achieves versatile voltage regulation by controlling the switch duty cycle and operating frequency, eliminating the need for separate boost and buck circuits.
Solution Approach 2:
The patent changes operating parameters (switching frequency and duty cycle) of a single buck converter to achieve different voltage regulation outcomes. By dynamically adjusting these parameters, the circuit can adapt to both voltage boosting and decreasing requirements without adding physical components.
2Measurement precision
If a current comparator is used to regulate switch timing, then precise current control is achieved, but the circuit becomes more complex and costly
Solution Approach 1:
The patent extracts and removes the current comparator component from the circuit. Instead of using a current comparator to measure and regulate current, the invention uses a simplified approach where the switch timing is controlled based on voltage measurements and predetermined timing relationships, eliminating the need for complex current sensing and comparison circuitry.
Solution Approach 2:
The circuit uses the inherent properties of the inductor and the control timing to self-regulate current flow. The predetermined first and second time periods are configured so that the inductor naturally limits current without requiring active current measurement or comparison, allowing the circuit to self-regulate through proper timing design.
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 approach results in a more compact, cost-effective LED driver circuit that efficiently maintains a constant current through the LED load, eliminating the need for complex current measurement circuits and reducing component count, making it suitable for applications where space and cost are critical.
Implementation Method 1
supplying an input voltage to an inductive element, drawing a current through the inductive element for a first predetermined time period, and supplying a current from the inductive element to a first terminal of the LED load during a second time period
Data Source
AI summary
The invention relates to a method for controlling an LED load. First an input voltage is supplied to an inductive element. Subsequently, a current is drawn through the inductive element for a first predetermined time period. Finally, a current is supplied from the inductive element to a first terminal of the LED load during a second time period. The first predetermined time is controlled to maintain a predetermined average current through the LED load.