LED Driver Open Circuit Protection and Color Adjustment
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Solution Overview
Problem
Conventional LED lamp driving devices lack effective open circuit protection and flexibility in adjusting light color, leading to reduced product quality, increased defective rates, and higher production costs due to fixed ratios of blue and yellow LEDs.
Innovation Solution
An LED driving device with open circuit protection and color temperature adjustment, utilizing a boost power conversion circuit with a switch to control the conduction status of blue and yellow LED strings, allowing for flexible color adjustment and protection against overvoltage by forming a node between LED strings and using a control chip coupled with a transistor and sensing resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ratio of blue and yellow LEDs is fixed at the R&D stage, then the device structure is simple, but the adaptability is poor and defective rate increases
Solution Approach 1:
The patent implements dynamic adjustability of LED string conduction status through a switch component. The switch can selectively connect or disconnect different LED strings (blue or yellow) based on required light color output, transforming a static fixed-ratio system into a dynamic adjustable system. This resolves the contradiction by enabling adaptability without requiring complex control circuits, as the switching mechanism is simple and direct.
2Reliability
If open circuit protection is not implemented, then the device complexity is low, but the reliability decreases due to overvoltage damage
Solution Approach 1:
The patent employs a self-service protection mechanism where the control chip automatically detects open circuit conditions through its built-in control logic and sensing resistor. When an LED string opens, the voltage at the node changes, and the control chip responds by adjusting the PWM duty cycle or shutting down the corresponding string, eliminating the need for separate protection circuits. This achieves reliable protection while maintaining simple device structure.
3Manufacturing precision
If manufacturers eliminate products with color difference issues, then the product quality is high, but the productivity decreases due to poor yield rate
Solution Approach 1:
The patent enables post-production adjustment of light color parameters by allowing selective conduction of blue or yellow LED strings through the switch. Products that initially have color temperature deviations can be adjusted to meet specifications by changing which LED string is active. This transforms a quality rejection scenario into a quality adjustment scenario, improving yield rate while maintaining high product quality standards.
Data Source
AI summary
An LED driving device with open circuit protection and color temperature and brightness adjustment is applied in a lamp to drive LEDs which are divided into strings, and at least one string is formed by connecting blue light diodes in series, and the remaining strings are formed by connecting yellow light LEDs in series, and at least one of the yellow light strings is connected to the blue light string in parallel and then connected to the remaining strings in series to form a node. The LED driving device employs a switch to conduct the blue or yellow light string to change the color temperature of the emitted light of the lamp, and a power input pin of a control chip is electrically coupled to the node. If there is an open circuit caused by an abnormality of the LEDs, the operation will be stopped to provide protection.