As a wholesale led light supplier, Eurborn has own exterior factory and mold department, it is professional in manufacturing outdoor lights, and knows every parameter of the product well. Today, I will share with you how to distinguish between constant voltage and constant current of LED drive power.
1. Constant current power supply means that the current flowing through the load remains unchanged when the power supply changes. Constant voltage power supply means that the power supply voltage does not change when the current flowing through the load changes.
2. The so-called constant current/constant voltage means that the output current/voltage remains constant within a certain range. The premise of "constant" is within a certain range. For "constant current", the output voltage should be within a certain range, and for "constant voltage", the output current should be within a certain range. Beyond this range "constant" cannot be maintained. Therefore, the constant voltage source will set the parameters of the output current file (maximum output). In fact, there is no such thing as "constant" in the electronic world. All power supplies have an indicator of load regulation. Take the constant voltage (voltage) source as an example: as your load increases, the output voltage must drop.
3. The difference between constant voltage source and constant current source in definition:
1) Under the condition of allowable load, the output voltage of the constant voltage source is constant and will not change with the change of the load. Usually used in low-power LED modules, and low-power LED strips are often used. The constant voltage source is what we often call a regulated power supply, which can ensure that the voltage remains unchanged when the load (output current) changes.
2) Under the condition of allowable load, the output current of the constant current source is constant and will not change with the change of the load. It is usually used in high-power LEDs and high-end low-power products. If the test is good in terms of life, the constant current source LED driver is better.
The constant current source can adjust its output voltage accordingly when the load changes, so that the output current remains unchanged. The switching power supplies we have seen are basically constant voltage sources, and the so-called "constant current switching power supply" is based on the constant voltage source, and a small resistance sampling resistor is added to the output. The front stage goes to control for constant current control.
4. How to identify whether it is a constant voltage source or a constant current source from the power supply parameters?
It can be seen from the label of the power supply: if the output voltage it identifies is a constant value (such as
Vo=48V), it is a constant voltage source: if it identifies a voltage range (for example, Vo is 45~90V), it can be determined that this is a constant current source.
5. Advantages and disadvantages of constant voltage source and constant current source: constant voltage source can provide constant voltage for load, ideal constant voltage source
The internal resistance is zero and cannot be short-circuited. The constant current source can provide constant current to the load, and the ideal constant current source has infinite internal resistance big, can't open the way.
6. LED is an electronic component that works with constant current (the working voltage is relatively fixed, and a slight offset of it will cause a great change in the current). Only by using the constant current method can the consistent brightness and long life be truly guaranteed. When the constant voltage driving power supply is working, it is necessary to add a constant current module or a current limiting resistor to the lamp, while the constant current driving power supply only has the constant current module of the constant voltage source built-in.
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Post time: Sep-21-2022