Smart Dummy-Load System for LED Afterglow Reduction
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Solution Overview
Problem
LED driving circuits experience significant low-frequency ripples due to filter capacitors, leading to a slow voltage drop and afterglow phenomenon when power is cut off, causing LEDs to remain lit after intended shutdown.
Innovation Solution
A smart dummy-load electricity consumption system comprising a switching detection module and a discharge module, which includes a series-connected inductor-capacitor filter circuit, a counter, Schmitt triggers, and an AND gate logic control system to rapidly discharge the capacitor by switching the circuit to ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-capacity filter capacitor is added at the output end of the LED driving circuit to minimize low-frequency ripples, then the ripple reduction is improved, but the voltage drop speed deteriorates causing afterglow when power is cut off
Solution Approach 1:
The patent extracts the harmful function of the filter capacitor (slow voltage drop causing afterglow) by introducing a separate discharge circuit. The discharge circuit selectively activates only when power is cut off, separating the capacitor's dual functions: maintaining voltage during operation and enabling rapid discharge during shutdown. This resolves the contradiction by removing the harmful effect while preserving the beneficial ripple filtering function.
Solution Approach 2:
The patent introduces a discharge circuit as an intermediary component between the filter capacitor and ground. This intermediary circuit, controlled by a detection module, provides a controlled discharge path that activates only when needed (during power cutoff). The intermediary discharge circuit mediates between the capacitor's energy storage function and the requirement for rapid voltage drop, resolving the contradiction through conditional intervention.
2Ease of operation
If a conventional dummy-load resistor is used to discharge the capacitor, then the discharge function is provided, but the discharge time remains long due to non-linear discharge characteristics
Solution Approach 1:
The patent transforms the static discharge characteristic of conventional dummy-load resistors into a dynamic discharge process. By using a constant-current discharge circuit controlled by detection modules and logic gates, the discharge current is actively regulated to maintain linearity throughout the discharge process. This dynamic control enables the discharge time to be precisely managed and significantly reduced compared to passive resistor-based discharge.
Solution Approach 2:
The patent changes the discharge parameter from constant resistance (conventional dummy-load) to constant current through active control. The detection modules monitor voltage and current parameters in real-time, and the logic gates adjust the discharge circuit operation to maintain optimal discharge parameters. This parameter transformation from resistive to current-controlled discharge achieves linear discharge characteristics and dramatically reduces discharge time.
3Use of energy by moving object
If the LED driving circuit is switched off to stop LED operation, then the power consumption is reduced, but the LED remains lit for some time due to energy stored in the filter capacitor
Solution Approach 1:
The patent applies preliminary anti-action by preparing a discharge circuit that activates in advance of the actual need for complete LED shutdown. When power cutoff is detected, the discharge circuit immediately begins draining the capacitor energy before it can sustain LED operation. This preemptive discharge action prevents the afterglow phenomenon by counteracting the capacitor's energy storage effect before it can cause prolonged illumination.
Solution Approach 2:
The patent converts the harmful effect of stored energy in the filter capacitor (causing afterglow) into a beneficial controlled discharge process. By detecting the power cutoff condition and activating a constant-current discharge circuit, the stored energy is systematically extracted and dissipated in a controlled manner. This transforms the harmful prolonged illumination into a beneficial rapid, linear discharge that achieves immediate LED shutdown while efficiently utilizing the stored energy.
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
The system effectively addresses the afterglow issue by rapidly switching the LED circuit to ground, providing immediate shutdown and linear energy discharge, unlike conventional dummy-load resistors, thereby shortening discharge time.
Implementation Method 1
add a high-capacity filter capacitor at the output end of the LED driving circuit in order to minimize the ripples
Implementation Method 2
rapidly switching the LED circuit to ground... providing immediate shutdown and linear energy discharge
Data Source
AI summary
The present invention provides a smart dummy-load electricity consumption system, comprising: a switching detection module and a discharge module. The switching detection module comprises a power source input module and a filter circuit provided at an output of the power source input module, wherein the filter circuit supplies electricity to a working unit, the output of the power source input module is connected with a first controller, and the filter circuit has an output connected with a second controller. The discharge module comprises a switch unit connected to the working unit and a logic gate for turning on or off the switch unit, wherein the logic gate has an input end connected to an output end of the first controller, has an input end connected to an output end of the second controller, and is configured to output a control signal for turning on or off the switch unit.