LED Light Source Standby Glow Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LED light sources in standby mode experience undesirable glow due to leakage currents flowing through parasitic capacitances, even when the mains supply is connected.
Innovation Solution
A current control element and a controllable switch are used to maintain the LEDs in a non-conductive state during standby mode, suppressing leakage currents by ensuring the controllable switch becomes non-conductive when the DC-DC converter operation is stopped, often utilizing a diode or FET, and a capacitor is used to isolate the LED load from the mains supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the LED light source is put in standby mode by stopping the DC-DC converter operation, then energy consumption is reduced, but leakage currents flow through parasitic capacitances causing unwanted glow
Solution Approach 1:
The patent extracts and removes the harmful leakage current path from the system by opening the switch S1, which disconnects the LED load from the parasitic capacitances connected to the mains supply. This separation eliminates the glow effect while maintaining standby energy savings.
Solution Approach 2:
The switch S1 acts as an intermediary element between the DC-DC converter output and the LED load. By controlling this intermediate switch, the patent can isolate the LED load from leakage currents while maintaining the ability to quickly resume normal operation when needed.
2Object-generated harmful factors
If the switch is opened to block leakage currents, then the glow effect is eliminated, but the response time to resume operation increases
Solution Approach 1:
The switch S1 is opened in advance during standby mode to prevent glow, but remains in a ready state that allows immediate closure when operation is needed. This preliminary positioning of the switch enables both glow prevention and fast response time without compromise.
3Reliability
If a transformer is used for isolation, then safety is improved, but leakage currents still flow through parasitic capacitances
Solution Approach 1:
The patent applies a localized solution by introducing switch S1 specifically at the LED load connection point, rather than relying solely on transformer isolation. This local intervention blocks leakage currents at their destination while preserving the transformer's safety isolation function.
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
Effectively prevents the generation of small amounts of light during standby mode by blocking leakage currents, eliminating the unwanted glow effect.
Implementation Method 1
the first controllable switch is rendered non-conductive. As a result, leakage currents flowing from the mains supply to the LED load via parasitic capacitances are effectively suppressed
Implementation Method 2
a capacitor is coupled between the primary winding and the secondary winding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a LED light source comprising: input terminals (Kl, K2) for connection to a mains voltage supply source, a rectifier (RB) coupled to the input terminals for rectifying the mains supply voltage supplied by the mains supply voltage source and comprising rectifier output terminals, a DC-DC converter (CONV) for generating a DC current out of the rectified mains supply voltage, comprising converter input terminals connected to the rectifier output terminals and comprising a first converter output terminal (A) and a second converter output terminal (B), - a LED load (LL) with an anode coupled to the first converter output terminal via a current control element (D5) for blocking a current flowing from the anode of the LED load to the first converter output terminal, and with a cathode coupled to the second converter output terminal via a first controllable switch (Ml) having a control electrode coupled to first control circuitry for rendering the controllable switch non-conductive in case the LED light source is in standby mode.