Active Bleeder Circuit for LED Dimmers
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Solution Overview
Problem
Existing bleeder circuits for phase cutting dimmers and light emitting diode (LED) circuits offer limited options and result in high power consumption due to the need for a minimum current to operate and detect phase changes, especially when the voltage is below the LED's threshold, leading to inefficiencies and increased standby consumption.
Innovation Solution
The implementation of an active bleeder circuit with a current limiting circuit and control circuitry that uses information from the LED current to adjust and control the current flow, including a rectifier for converting AC to DC voltage, and a microprocessor for advanced control, allowing for reduced power consumption and adaptive operation based on dimmer types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive element (resistor) is used in the bleeder circuit, then the circuit structure is simple, but the power consumption is high and the options for improvement are limited
Solution Approach 1:
The patent replaces the passive resistor-based bleeder circuit with an active electronic circuit comprising operational amplifiers, transistors, and controlled current sources. This substitution enables intelligent control of the bleeder current based on detected voltage conditions, allowing the circuit to minimize power consumption while maintaining compatibility with phase-cutting dimmers.
Solution Approach 2:
The patent dynamically changes the bleeder current parameter based on the detected voltage conditions. The control circuit adjusts the current magnitude and timing according to the phase-cutting waveform detection, optimizing power consumption at different operating points rather than maintaining a fixed high current as in passive resistor designs.
2Reliability
If a higher current is supplied to the bleeder circuit to ensure stable operation of the phase cutting dimmer, then the dimmer operates reliably, but the power consumption increases
Solution Approach 1:
The patent implements a dynamic bleeder current that adapts to the instantaneous voltage conditions. The control circuit detects the phase-cutting waveform and adjusts the current magnitude and timing accordingly, providing sufficient current during critical detection periods while minimizing current during other phases, thus maintaining reliability while reducing overall power consumption.
Solution Approach 2:
The patent employs periodic current pulses synchronized with the AC mains frequency and the phase-cutting waveform. The bleeder current is activated in specific time windows during each half-cycle to ensure proper dimmer operation and phase detection, rather than flowing continuously, thereby reducing average power consumption while maintaining operational stability.
3Measurement precision
If the bleeder circuit operates continuously to maintain minimum current, then the phase cutting dimmer can detect phase and zero crossing accurately, but the standby power consumption increases
Solution Approach 1:
The patent uses the bleeder current to create preliminary voltage conditions that enable the phase-cutting dimmer to detect the phase and zero-crossing points accurately. By providing controlled current during specific detection windows before the main load operates, the circuit ensures measurement precision without requiring continuous current flow, thus reducing standby consumption.
Solution Approach 2:
The patent maintains continuous monitoring and adaptive control of the bleeder current to ensure uninterrupted phase detection capability. The control circuit continuously detects the voltage waveform and adjusts the current in real-time, ensuring that the minimum current requirement for accurate phase and zero-crossing detection is met whenever needed, while minimizing current during periods when detection is not critical.
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 active bleeder circuit significantly reduces power consumption by limiting current only when necessary, optimizing operation with dimmers and LEDs, and minimizing standby power usage, while being cost-effective and efficient.
Implementation Method 1
a rectifier for converting AC to DC voltage
Data Source
AI summary
Bleeder circuits (1) for combinations of phase cutting dimmers (2) and light emitting diode circuits (3) comprise active circuitry (4) to increase a number of options. The active circuitry (4) may comprise a current limiting circuit (5) for limiting a current flowing through the bleeder circuit (1). The active circuitry (4) may comprise a voltage detecting circuit (6) for activating or deactivating, in response to a detection result, the current limiting circuit (5) and may comprise control circuitry such as a micro processor circuit (7) for controlling the current limiting circuit (5) and may comprise a control circuit (9) for using information derived from a current flowing through the light emitting diode circuit (3) for controlling the current limiting circuit (5) and for controlling at least a part of the light emitting diode circuit (3) that comprises anti-parallel light emitting diodes (31-32) or serial and/or parallel light emitting diodes (33-36).