LCC Driver Turn-On Optimization via Duty Cycle Table
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Solution Overview
Problem
Conventional LCC topology for constant current drivers in solid state light sources results in slow loop response and unstable turn on time, leading to overshooting or undershooting of desired output current, causing instability and flashing of light sources.
Innovation Solution
Implementing a pre-determined table of duty cycle values within the driver to adjust the switching frequency of the LCC tank circuit, allowing for rapid stabilization of output current without flashing, using a feedback circuit that applies adjustment coefficients based on current comparison results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an LCC topology is used for constant current driver, then the circuit complexity is reduced, but the turn on time becomes slow and causes output current instability
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal duty cycle values in a lookup table before operation. During turn-on, the controller directly retrieves the pre-determined duty cycle corresponding to the target current, eliminating the need for slow real-time calculations and enabling immediate stable current output without flashing.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual output current and comparing it with the target current. Based on the current comparison result, the controller adjusts the duty cycle of the LCC tank circuit in real-time, ensuring the output current stabilizes quickly at the desired level and preventing flashing phenomena.
2Device complexity
If an LCC topology is used for constant current driver, then the device structure is simplified, but the response speed becomes slow causing overshooting or undershooting
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal duty cycle values in a lookup table before operation. During turn-on, the controller directly retrieves the pre-determined duty cycle corresponding to the target current, eliminating the need for slow real-time calculations and enabling immediate stable current output without flashing.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual output current and comparing it with the target current. Based on the current comparison result, the controller adjusts the duty cycle of the LCC tank circuit in real-time, ensuring the output current stabilizes quickly at the desired level and preventing flashing phenomena.
3Reliability
If a buck converter is used instead of LCC topology, then the turn on time is reduced, but the device complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal duty cycle values in a lookup table before operation. During turn-on, the controller directly retrieves the pre-determined duty cycle corresponding to the target current, eliminating the need for slow real-time calculations and enabling immediate stable current output without flashing.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual output current and comparing it with the target current. Based on the current comparison result, the controller adjusts the duty cycle of the LCC tank circuit in real-time, ensuring the output current stabilizes quickly at the desired level and preventing flashing phenomena.
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
Enables a stable output current to be reached within a short time (less than one second), preventing flashing and ensuring the stability of solid state light sources.
Implementation Method 1
an LCC topology, including an inductor and two capacitors in a tank circuit configuration
Implementation Method 2
a feedback circuit of the driver. The feedback circuit adjusts a switching frequency of the LCC tank circuit
Data Source
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AI summary
Systems, methods, and computer program products for turn on optimization of a driver for one or more light sources are disclosed. A duty cycle value is selected from a table. The selected duty cycle corresponds to the target output current of the driver and has a corresponding voltage. The selected duty cycle is applied to the driver. An output voltage at the light source is measured, and compared to the corresponding voltage of the selected duty cycle to produce a voltage comparison result. Based on the comparison result, the selection of the duty cycle is adjusted. Additionally, an output current of the light source is measured and compared to the target output current, to produce a current comparison result. An adjustment coefficient is applied to a feedback circuit of the driver based thereon, wherein the feedback circuit adjusts a switching frequency of the driver based on the selected duty cycle.