LED Bleeder Circuit for Deep Dimming via Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bleeder circuits for light emitting diode (LED) dimming operations require complex connections and configurations to detect and bypass leakage currents, leading to inefficiencies and limitations in dimming capabilities, particularly in deep dimming scenarios.
Innovation Solution
A bleeder circuit that detects the amplitude of the feeding current flowing through the LED circuit and introduces a bleeder current based on this detection, eliminating the need for additional connections to the dimmer or converter, allowing for integration with the LED circuit and shared heat sinks, and incorporating detection and introduction circuits with transistors and resistors for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing bleeder circuits use detection circuits and active elements connected between the dimmer and LED drive circuit to detect and bypass leakage current, then leakage current can be detected and bypassed, but the device complexity increases due to several additional connections required for the detection circuit and active element
Solution Approach 1:
The patent merges the bleeder circuit with the LED drive circuit by integrating the detection and current introduction functions into the existing drive circuit architecture. The detection circuit detects the feeding current that flows through the LED circuit, and the same circuit introduces the bleeder current, eliminating the need for separate detection circuits and active elements connected between the dimmer and LED drive circuit. This integration reduces the number of additional connections while maintaining leakage current detection and bypass capabilities.
Solution Approach 2:
The LED drive circuit performs self-detection of leakage current by monitoring its own feeding current. The detection circuit within the drive circuit detects the amplitude of the feeding current flowing through the LED circuit, and the same circuit automatically introduces the appropriate bleeder current without requiring external detection circuits or additional active elements. This self-service approach simplifies the overall device complexity.
2Ease of manufacture
If bleeder circuits are located near the light emitting diode circuit without additional connections to dimmer or converter, then integration and thermal management are simplified, but the ability to detect and control bleeder current based on external power envelope edges is limited
Solution Approach 1:
The patent uses the feeding current flowing through the LED circuit as an intermediary to convey information about the power envelope edges from the dimmer to the bleeder circuit. Instead of requiring direct connections to the dimmer or converter, the detection circuit monitors the feeding current amplitude, which indirectly reflects the power envelope conditions. This intermediary approach allows the bleeder circuit to be located near the LED circuit for easy integration and thermal management while still maintaining reliable dimming operation improvement capability.
Solution Approach 2:
The patent replaces the mechanical/connection-based approach (direct wiring to dimmer or converter) with an electrical signal-based approach. The detection circuit electronically monitors the feeding current amplitude to detect power envelope edges, substituting physical connections with electrical signal processing. This allows the bleeder circuit to be integrated near the LED circuit without additional external connections while maintaining the ability to improve dimming operation.
Data Source
AI summary
Bleeder circuits (1) comprise detection circuits (11) for detecting values of amplitudes of feeding currents for feeding light emitting diode circuits (2) and comprise introduction circuits (12) for introducing bleeder currents. Values of amplitudes of bleeder currents are defined in response to detection results from the detection circuits (11). As a result, disadvantageous connections between the bleeder circuits (1) and dimmers (4) are avoided, and the bleeder circuits (1) can be located near the light emitting diode circuits (2) and they can use the same heat sink. The detection circuit (11) may comprise a first resistor circuit (31), and the introduction circuit (12) may comprise a first transistor circuit (41). The detection circuit (11) may further comprise a second resistor circuit (32) for coupling the first transistor circuit (41) to the first resistor circuit (31) and may comprise an operational amplifier (51) or a second transistor circuit (42) for controlling the first transistor circuit (41).