Voltage Snubber Circuit for LED String Startup Protection
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Solution Overview
Problem
Conventional voltage snubber circuits react slowly to limit overvoltage conditions in LED systems, leading to potential damage from higher initial voltages in constant current power supplies, as they are not effective in preventing voltage spikes during startup.
Innovation Solution
A voltage snubber circuit that includes a power source, voltage regulator, RC time delay, AC regulator, pull down resistor, transistor, and transient voltage suppression diodes, which dynamically bypasses the LED string during startup to prevent voltages above a threshold, using a constant current power supply to maintain a constant current and adjust voltage based on load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage snubber circuits are used to suppress overvoltage conditions, then voltage spikes are limited, but the reaction time is slow causing LEDs to remain in overvoltage conditions for an undesirable period
Solution Approach 1:
The circuit performs preliminary action by proactively detecting the startup condition of the power supply before the voltage spike occurs. The AND gate receives the power good signal and the inverter converts it to activate the MOSFET Q1 in advance, creating a protective path before the dangerous voltage rise happens. This preemptive activation eliminates the slow reaction time of conventional snubbers.
Solution Approach 2:
The MOSFET Q1 acts as an intermediary device that dynamically switches to create a bypass path for the voltage spike. When activated, it provides a low-impedance path that shunts the harmful voltage away from the LEDs. This intermediary mechanism enables faster response compared to passive conventional snubber circuits.
2Productivity
If constant current power supply initializes with higher voltage to establish current flow, then current regulation is achieved, but the initial higher voltage can destroy or damage conventional LEDs
Solution Approach 1:
The harmful initial voltage spike is extracted from the path to the LEDs by routing it through the MOSFET Q1 and diode D1 bypass path. The circuit separates the voltage establishment function (which occurs through the bypass) from the LED operation, allowing the power supply to initialize with high voltage without exposing the LEDs to damaging overvoltage conditions.
Solution Approach 2:
The potentially harmful initial voltage surge is converted into a beneficial initialization process. By directing the high voltage through the MOSFET-Q1 and diode-D1 path, the circuit uses the very voltage that would normally damage LEDs to establish current flow in the power supply, then safely transitions to normal operation. The harmful overvoltage becomes a controlled initialization mechanism.
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 higher voltages from being applied to the LED string by dynamically adjusting the voltage supplied, reducing the risk of damage from overvoltage conditions and ensuring the LED string operates within a safe voltage threshold.
Implementation Method 1
The RC time delay circuit may be positioned between the voltage regulator circuit and the RC regulator, and may be configured to form a RC time delay to turn on the transistor.
Implementation Method 2
The first and second diodes may be transient voltage suppression diodes that are configured to divert or shunt voltage spikes from a circuit in order to protect the LED string from over voltage conditions.
Data Source
AI summary
Examples of the present disclosure are related to systems and methods for a voltage snubber circuit utilizing with light fixtures. More particularly, embodiments disclose a voltage snubber that is configured to prevent higher voltages being applied to a light emitting diode (LED) string.