LED Backlight Matrix Driving Circuit Voltage Regulation
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Solution Overview
Problem
Existing LED backlight driving circuits have poor flexibility and long regulation times for adjusting the driving voltage, and they require complex circuit structures with multiple comparators, increasing wiring area and cost.
Innovation Solution
The proposed LED backlight driving circuit incorporates an ADC voltage detection circuit with a driving controller to accurately measure and regulate the voltage at the negative terminal of the LED string, using threshold settings to determine the state of the LED string and adjust the driving voltage accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a comparator circuit is used to detect the voltage value at the negative terminal of the LED string, then the detection function is achieved, but the measurement precision is insufficient because the comparator can only output high-low signals and cannot directly output the accurate voltage value
Solution Approach 1:
The patent replaces the comparator-based detection mechanism with an ADC (analog-to-digital converter) module. The ADC directly converts the analog voltage signal at the negative terminal into a digital value, eliminating the need for comparator circuits and enabling precise voltage measurement without the limitations of binary high-low signal output.
Solution Approach 2:
The patent introduces an ADC module as an intermediary between the voltage detection point and the driving chip. This ADC module serves as a mediator that accurately converts the voltage signal into digital data, which is then processed by the driving chip to determine LED string states and regulate driving voltage, thereby improving measurement precision while simplifying the overall detection system.
2Measurement precision
If feedback regulation of the driving voltage is performed repeatedly many times to meet the set value, then the voltage regulation accuracy is improved, but the regulation time becomes excessively long
Solution Approach 1:
The patent implements preliminary action by using the ADC to detect the actual voltage value at the negative terminal in advance. Based on this accurate detection, the driving chip calculates the required regulation amount and directly adjusts the driving voltage to the target value in a single step, rather than performing repeated incremental adjustments. This preliminary detection and calculation approach significantly reduces regulation time while maintaining high accuracy.
Solution Approach 2:
The patent employs feedback by continuously monitoring the voltage at the negative terminal through the ADC and using this information to regulate the driving voltage. The driving chip receives the digital voltage value from the ADC, compares it with the target value, and adjusts the driving voltage accordingly. This closed-loop feedback mechanism ensures accurate voltage regulation while minimizing regulation time through intelligent control algorithms.
3Reliability
If three comparators are connected to each LED string channel in the detection unit, then the detection function is achieved, but the wiring area and chip cost increase significantly
Solution Approach 1:
The patent merges the functions of multiple comparators into a single ADC module. Instead of using three separate comparators for each LED string channel, the ADC integrates the voltage detection function for all channels, converting analog voltage signals into digital values. This consolidation significantly reduces the wiring area and the number of components required on the chip while maintaining reliable detection functionality.
Solution Approach 2:
The patent implements universality by designing the ADC module to serve multiple LED string channels simultaneously. The ADC acts as a multi-functional component that can detect voltage values from different channels, replacing the need for dedicated comparator circuits for each channel. This multi-functional approach reduces chip complexity, wiring area, and manufacturing cost while ensuring reliable detection across all channels.
Data Source
AI summary
An LED backlight driving circuit with a voltage regulating unit is provided. The LED backlight driving circuit includes a power supply unit, an LED string, an ADC voltage detection circuit, and a driving controller; the ADC voltage detection circuit is used to detect a voltage value Vled of a negative terminal of a LED string, and the ADC voltage detection circuit includes an ADC sampling module that converts the measured voltage value Vled at the negative terminal of the LED string into a voltage numerical code; for the numerical code of the negative terminal voltage value Vled measured by the ADC sampling module, a first threshold V1 and a second threshold V2 are set.