LED Driving Circuit Delay Control for Voltage Stability
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Solution Overview
Problem
LED light emitting devices face challenges in maintaining a stable power supply voltage, particularly when the duty cycle of the dimming signal is short, leading to reduced power supply voltage and potential failure to operate LED channels due to insufficient current flow.
Innovation Solution
The implementation of an error generator and delay circuit in the LED light emitting device to detect minimum channel voltages, amplify differences, and generate an error amplifying signal, along with a power supply that includes a transformer and switch control circuit to manage power switching based on feedback signals, ensuring a secure and stable power supply voltage by extending the duty cycle of the dimming signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the duty cycle of the dimming signal is shortened to control brightness, then the light emission control precision is improved, but the power supply voltage becomes insufficient to operate the LED channel
Solution Approach 1:
The patent applies preliminary action by introducing a delay circuit that extends the duty cycle of the dimming signal before it reaches the LED channel. The delay circuit adds a predetermined delay period to the dimming signal, ensuring that the power supply voltage has sufficient time to stabilize and reach the required level before the LED channel is activated. This preliminary extension of the duty cycle prevents voltage insufficiency while allowing the final effective duty cycle to remain short for precise brightness control.
2Duration of action of moving object
If the duty cycle of the dimming signal is shortened, then the light emission duration is reduced, but the power supply voltage cannot be generated in sufficient time
Solution Approach 1:
The delay circuit performs preliminary action by extending the duty cycle of the dimming signal with a predetermined delay period. This ensures that the power supply has adequate time to generate and stabilize the required voltage before the LED channel activation. The extension is temporary and only applies during the critical voltage generation phase, after which the normal short duty cycle effect is achieved for light emission control.
3Stability of the object's composition
If the power supply voltage is reduced to extend the delay period, then the voltage stability is improved, but the LED channel cannot operate due to insufficient current
Solution Approach 1:
The delay circuit applies preliminary action by temporarily extending the duty cycle to allow the power supply voltage to stabilize before LED channel activation. During this extended delay period, the power supply voltage reaches its stable operating level, ensuring that when the LED channel is activated, sufficient current is available for reliable operation. The extension is precisely controlled and only applied when necessary to ensure voltage stability.
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 ensures a stable power supply voltage to LED channels, preventing operational failures and maintaining consistent light emission by compensating for short duty cycles of the dimming signal, thereby ensuring reliable operation of the LED light emitting device.
Implementation Method 1
a transformer including a primary coil for receiving an input voltage and a secondary coil for generating an output voltage
Implementation Method 2
a feedback signal transmitter for generating a feedback voltage through a photocoupler for receiving the feedback signal according to the enable signal
Data Source
AI summary
The present invention relates to an LED light emitting device and a driving method thereof. The LED light emitting device supplies a power supply voltage to at least two LED channels. The LED light emitting device samples channel voltages of the at least two LED channels to detect a minimum voltage from among the sampled voltages, and amplifies a difference between the detected minimum voltage and a predetermined reference voltage to generate an error amplifying signal. The LED light emitting device generates an enable signal having a duty extended by a predetermined delay period from a duty of a dimming signal for controlling light emission periods of the at least two LED channels. In this instance, the error generator is operable by the enable signal.