LED Constant-Current Power Circuit With Output Power Limiting
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Solution Overview
Problem
Constant current LED power supplies with existing circuit structures face issues with high DC output ripple and large voltage differences between input and output, leading to excessive temperature rise during overload tests, which prevents them from passing the overload test standard.
Innovation Solution
Incorporating a voltage stabilizing source circuit and an output power limiting circuit with resistors, capacitors, and diodes to reduce the DC-DC output current and limit the maximum output power, utilizing the clamping function between diodes to control the voltage and current, thereby reducing the load power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage difference between DC-DC input and output is increased to improve single-stage power supply efficiency, then the efficiency of the single-stage power supply is improved, but the temperature rise during overload test becomes excessive and the overload test standard cannot be passed
Solution Approach 1:
The patent applies preliminary action by setting a maximum output power limit before overload conditions occur. The limiting circuit pre-configures the system to cap the output power at a safe level, preventing excessive temperature rise during overload tests while maintaining normal operating efficiency. This is achieved through the voltage stabilizing source circuit and output power limiting circuit that establish power boundaries in advance.
Solution Approach 2:
The patent changes the power parameter by introducing a maximum output power limit through the limiting circuit. By modifying the power parameter from unlimited to capped at a specific maximum value, the system can maintain efficient operation within safe boundaries while passing overload tests. The limiting circuit dynamically adjusts the output power parameter based on the voltage difference between input and output.
2Reliability
If a maximum output power limit is set to pass overload tests, then the overload test standard is passed, but the load power is reduced
Solution Approach 1:
The patent applies dynamics by making the power limit adaptive rather than fixed. The limiting circuit dynamically adjusts the maximum output power based on real-time conditions, allowing the system to operate at full power when safe and automatically reducing power only when necessary to meet test standards. This dynamic adjustment maintains reliability while maximizing usable power output.
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
The solution effectively limits the output load power, preventing excessive temperature rise and allowing the constant current LED power supply to pass the overload test standard by reducing the DC-DC output current and voltage in proportion, thus ensuring compliance with test standards.
Implementation Method 1
utilizing the clamping function between diodes to control the voltage and current
Data Source
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AI summary
The invention relates to a constant current LED power supply circuit with maximum output power limiting circuit, including a single-stage constant voltage power supply circuit, a DC-DC constant current output circuit, and a maximum output power limiting circuit of constant current LED power supply. By adding a voltage stabilizing source circuit for setting DC-DC output current and an output power limiting circuit to an existing constant current LED power supply circuit, the voltage stabilizing source circuit for setting the DC-DC output current is connected to the output end of the single-stage constant voltage power supply circuit, and the output power limiting circuit is connected to the constant current output end of the DC-DC constant current output circuit, thereby utilizing the clamping function between the two diodes of the output power limiting circuit to pull down the voltage of the voltage stabilizing input end of the voltage stabilizing source circuit, and the voltage of the control end D of the DC-DC constant current output circuit also drops in the same proportion, thus, the DC-DC output current corresponding to the DC-DC constant current output circuit is greatly reduced by utilizing the control end D, which limits the output load power.