Dynamic Damper Circuit for Lighting Drivers
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Solution Overview
Problem
Inrush currents and voltage fluctuations in lighting driving circuits cause abnormal dimmer cut-off states and flickering of lighting elements due to electromagnetic interference, leading to potential damage and instability.
Innovation Solution
A dynamic damper is introduced in the lighting driving circuit, comprising a timing circuit and a damper circuit with adjustable resistor values, which switches between short-circuit, first working, and second working states to limit inrush currents by generating a dynamic damper resistor value based on charging and discharging loops, thereby reducing energy consumption and stabilizing the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dimmer is used to adjust brightness by cutting off leading or trailing edge of AC voltage, then brightness control is achieved, but sudden voltage rise occurs and inrush current is generated
Solution Approach 1:
The dynamic damper is activated before the main switching action of the dimmer to preemptively limit inrush current. The damper circuit is enabled at the beginning of each AC cycle and disabled after a predetermined time period, preparing the circuit in advance to prevent harmful current spikes before they occur.
Solution Approach 2:
The dynamic damper circuit acts as an intermediary component between the AC power source and the lighting element. It temporarily connects to the circuit during critical moments to limit inrush current, then disconnects to allow normal dimmer operation, serving as a mediator that protects the system without interfering with brightness control.
2Object-affected harmful factors
If EMI filter is added to reduce electromagnetic interference, then EMI is reduced, but inrush and vibrating current occur in input current
Solution Approach 1:
The damper resistance is dynamically adjusted over time rather than remaining fixed. The circuit transitions from a high-resistance state that limits inrush current to a low-resistance state that allows normal current flow, adapting its characteristics to different operational phases to address both EMI and vibrating current issues.
Solution Approach 2:
The dynamic damper operates periodically with each AC cycle, enabling itself for a predetermined time period at the beginning of each cycle to limit inrush current, then disabling itself to allow normal operation. This periodic activation pattern addresses the recurring nature of inrush current and vibrating current issues.
3Object-affected harmful factors
If fixed damper resistor is used to limit inrush current, then inrush current is limited, but energy consumption increases
Solution Approach 1:
The damper resistance transitions dynamically from a first resistance value that limits inrush current to a second resistance value that is lower or zero. This dynamic adjustment ensures high resistance is applied only when needed during the initial phase, then reduced to minimize energy consumption during normal operation.
Solution Approach 2:
The dynamic damper applies full resistance limitation only for the essential initial period needed to prevent inrush current, then reduces or removes the resistance for the remainder of the cycle. This partial application of damping action is sufficient to protect against inrush current while minimizing unnecessary energy loss.
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 dynamic damper effectively limits inrush currents, reduces energy consumption, and enhances the stability of the lighting driving circuit, preventing damage and flickering, while maintaining adjustable brightness and chroma control.
Implementation Method 1
a switch element and a capacitor, wherein the switch element is connected between a second end of the current source and a third end which is connected to a terminal D, the capacitor is connected between a first end of the current source and ground, a second end of the capacitor is connected to a control terminal of the switch element
Implementation Method 2
a resistance R1, wherein a first end of the resistance R1 is connected to a second end of the switch element, a second end of the resistance R1 is connected to a terminal D and a third end of the switch element
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A dynamic damper (240) in a lighting driving circuit (200) for limiting an inrush current includes a damper circuit (242) and a timing circuit (241) comprising capacitor (1). The damper circuit is connected to the timing circuit. When an input voltage is provided to the dynamic damper, the capacitor begins to be charged and the capacitance-voltage of the capacitor rises. The damper circuit enters to a first working state and generates a dynamic damper resistor value. When the capacitance-voltage of the capacitor is greater than a first threshold voltage, the damper circuit enters to a second working state and the dynamic damper resistor value begins to decrease. When the capacitance-voltage of the capacitor is greater than a second threshold voltage, the damper circuit enters to a short-circuit state, and the dynamic damper resistor value decreases to zero to facilitate the normal work of the power source converter.