Time-Delay Lighting Circuit Using Capacitor Energy Storage
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Solution Overview
Problem
LED lighting devices turn off immediately when disconnected from an external power source, leading to potential safety issues due to sudden darkness, which existing technologies fail to address effectively.
Innovation Solution
A time-delay lighting circuit and device that includes a voltage-current conversion circuit, energy storage and discharge device, charging controller, and switch status detection circuit, allowing the light emitting component to remain powered after the external power source is disconnected by utilizing stored energy when the control switch is switched off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If LED lighting device is disconnected from external power source, then energy saving is achieved, but sudden darkness causes safety issues
Solution Approach 1:
The energy storage and discharge device (capacitor) is pre-charged during normal operation when the control switch is on. This preliminary energy storage enables the lighting device to continue operating for a predetermined time after power disconnection, preventing sudden darkness and maintaining user safety.
Solution Approach 2:
The capacitor acts as an energy buffer that cushions the transition from powered to unpowered state. By storing energy beforehand and releasing it during the transition period, the system smooths out the abrupt change in illumination, providing a gradual fade-out effect that maintains visibility and safety.
2Duration of action of moving object
If energy storage and discharge device is added, then time-delay lighting is achieved, but device complexity increases
Solution Approach 1:
The control switch serves multiple functions: it controls the main lighting operation during powered mode and simultaneously triggers the energy storage/discharge circuit to enable delayed lighting during unpowered mode. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in device complexity.
Solution Approach 2:
The capacitor automatically charges when voltage from the external power source is detected and automatically discharges when the power source is disconnected. The circuit uses the presence or absence of external voltage to self-regulate the charging and discharging states without requiring additional control circuitry, thus minimizing added complexity.
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
Enables delayed lighting, enhancing safety by maintaining illumination after the power source is disconnected, thereby preventing sudden darkness and potential safety hazards.
Implementation Method 1
an energy storage and discharge device configured to provide power to the light emitting component when the control switch is switched off to disconnect the external power source from the time-delay lighting circuit
Data Source
AI summary
The present disclosure provides a time-delay lighting circuit and a lighting device. The time-delay lighting circuit includes a first voltage-current conversion circuit configured to convert a first inputted current to a current satisfying working conditions of the light emitting component; an energy storage and discharge device configured to provide power to the light emitting component when the control switch is switched off to disconnect the external power source from the time-delay lighting circuit; a charging controller configured to charge the energy storage and discharge device when the control switch is switched on to connect the external power source to the time-delay lighting circuit; and a switch status detection circuit configured to detect an on/off status of the control switch, and when the control switch is detected to be switched off, control the energy storage and discharge device to provide power to the light emitting component.