Single-Segment Linear LED Driver for Wide Input Voltage Efficiency
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Solution Overview
Problem
Single-segment linear LED drivers face challenges with narrow input voltage range and low efficiency due to excessive voltage drop and high voltage losses, limiting their application in various lighting and display systems.
Innovation Solution
A single-segment linear constant-power LED driving circuit comprising a voltage input module, power switch tube, sampling resistor, current control module, comparison module, and over-voltage control module, which adjusts the current flow and turn-off slope to maintain constant current and reduce power consumption across a wide input voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of LEDs connected in series is increased to raise output voltage and improve efficiency, then efficiency is improved, but the input voltage range becomes narrower
Solution Approach 1:
The patent introduces a dynamic control mechanism that adjusts the operating state of the LED string based on input voltage levels. When input voltage is high, the system enters a current reduction state; when input voltage is normal, the system operates in constant current mode. This dynamic adaptation allows the circuit to maintain high efficiency across a wide input voltage range, resolving the contradiction between efficiency and voltage range adaptability.
Solution Approach 2:
The patent changes the operating parameters of the LED driver based on input voltage conditions. By detecting input voltage level and switching between different operating modes (constant current mode and current reduction mode), the system optimizes efficiency for different voltage inputs. This parameter adaptation enables the circuit to handle both high and low input voltages effectively while maintaining high efficiency.
2Loss of energy
If HIGH-VOLTAGE DROP CURRENT TECHNOLOGY is used to reduce loss at high voltage, then voltage loss is reduced, but constant current effect deteriorates and efficiency improvement is limited
Solution Approach 1:
The patent implements a dynamic operating mode switching mechanism that transitions between constant current mode and current reduction mode based on detected input voltage levels. This dynamic approach maintains excellent constant current control during normal operation while enabling efficient current reduction when input voltage is high, thus resolving the contradiction between constant current precision and energy loss reduction.
Solution Approach 2:
The patent employs a feedback mechanism that continuously monitors input voltage and adjusts the operating state accordingly. The control circuit detects voltage levels and provides feedback to switch between operating modes, ensuring that constant current control is maintained when needed while enabling loss reduction when input voltage is high. This closed-loop feedback resolves the contradiction by making the system responsive to actual operating conditions.
Data Source
AI summary
A single-segment linear constant-power LED driving circuit and method. The circuit comprises: a voltage input module, an LED load, a power switch tube, a sampling resistor, an over-voltage control module for detecting the voltage at a drain terminal of the power switch tube, a current control module for limiting a peak current of the LED load, and a comparison module. When an input voltage is greater than a turn-on voltage of the LED load, the current control module limits the peak current so that the current average value in different input voltage periods is constant. When the input voltage is greater than a set value, current flowing through the LED load is turned off, thereby reducing power consumption. When the input voltage is less than the turn-on voltage of the LED load, the LED load is turned off.