Smart Lighting Pre-Charging Circuit Reduces LED Turn-On Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Smart lighting devices with filter capacitors greater than 10 uF experience prolonged restart times after soft switch-off, leading to poor user experience, especially when using low-cost components.
Innovation Solution
The implementation of a circuit design incorporating resistors R2, R3, R4, R5, and transistors Q1, Q2, which pre-charge the capacitor to a higher level during standby mode, reducing startup time by maintaining a higher loading level and using a reverse PWM signal to manage the pre-charging circuit, allowing for faster LED module activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter capacitor greater than 10 uF is used in smart lighting devices, then filtering performance is improved, but restart time after soft switch-off is prolonged
Solution Approach 1:
The patent implements a pre-charging circuit that activates during standby mode to charge the filter capacitor to a higher voltage level before the device is actually turned on. This preliminary action ensures that when the device needs to restart, the capacitor is already partially charged, significantly reducing the time required to reach full operating voltage and thereby reducing restart time while maintaining the benefit of a large filter capacitor for good filtering performance.
2Stability of the object's composition
If a large filter capacitor is used, then power supply stability is improved, but LED module activation time is delayed
Solution Approach 1:
The pre-charging circuit performs the useful action of charging the capacitor in advance during standby mode, so that when activation is needed, the capacitor is already at a higher voltage level. This resolves the contradiction by maintaining power supply stability through the large capacitor while eliminating the delay in activation.
Solution Approach 2:
The pre-charging circuit acts as an intermediary mechanism between the power supply and the LED module. It manages the capacitor charging process separately from the main power delivery path, allowing the large capacitor to maintain stability without directly delaying LED activation, as the pre-charged capacitor can quickly supply the necessary power surge.
3Loss of time
If a pre-charging circuit is added, then startup time is reduced, but device complexity increases
Solution Approach 1:
The pre-charging circuit is controlled by a simple standby mode detection mechanism that determines when to activate the pre-charging function. This keeps the control logic straightforward while achieving the benefit of reduced startup time through the preliminary charging action during standby periods.
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
This solution significantly reduces the turn-on time of LED modules by keeping the capacitor at a higher voltage level, thereby minimizing delays and improving the starting function of smart lighting devices.
Implementation Method 1
The rectifier is used for rectifying an AC (Alternating Current) input current to a first DC power
Implementation Method 2
The first DC-DC driver converts the first DC power to a second DC power supplying to the LED module
Implementation Method 3
A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. This effect is called electroluminescence
Implementation Method 4
The capacitor is connected to the LED module in parallel for filtering the second DC power
Data Source
AI summary
A lighting apparatus includes a LED (Light Emitted Diode) module, a wireless module, a rectifier, a first DC-DC (Direct Current to Direct Current) driver, a second DC-DC driver, a capacitor, a pre-charging circuit and a suppressing circuit. The first DC-DC driver converts the first DC power to a second DC power supplying to the LED module according to a PWM (Pulse Width Modulation) signal. The second DC-DC driver is used for converting the first DC power to a third DC power supplying to the wireless module. The capacitor is connected to the LED module in parallel for filtering the second DC power. The pre-charging circuit is used for pre-charging the capacitor in a stand-by mode. The wireless module receives the third DC power in the stand-by mode while the LED module is turned off in the stand-by mode.