Generally speaking, constant voltage power supply and constant current power supply are the two most important choices for driving LED lighting devices, and these two modes are currently relatively common driving methods on the market. In the process of designing and developing the LED power supply, engineers need to consider many factors when designing the driving selection of lighting devices. Below we will introduce how to distinguish the two modes of power supply from the definition, the advantages and disadvantages of the two modes of power supply, and how to distinguish between constant voltage power supply and constant current power supply by parameters.

  1. The difference in definition between constant voltage power supply and constant current power supply

1) The output voltage of the constant voltage power supply is constant under the permissible load and will not change with the change of the load. It is usually used in low-power LED modules and low-power LED light bars. Constant voltage power supply is what we often call a regulated power supply, which can ensure that the voltage remains the same when the load (output current) changes. Basically all the switching power supplies we usually use are constant voltage power supplies.

2) The output current of the constant current power supply is constant under the permissible load condition and will not change with the change of the load. In the case of load changes, the constant current power supply can adjust its output voltage accordingly, so that the output current remains unchanged, and is usually applied to high-power LED products.

  1. The advantages and disadvantages of constant voltage power supply and constant current power supply:

Constant voltage power supply (stabilized voltage source): A power supply capable of outputting a constant voltage to the load. The internal resistance of an ideal constant voltage power supply is zero, and it cannot be short-circuited during use.
Constant current power supply (constant current source): a power supply capable of outputting a constant current to the load. The internal resistance of an ideal constant current power supply is infinite, and it cannot be opened during use.

  1. How to distinguish constant voltage power supply and constant current power supply by parameters:

Get an LED power supply and find the label parameters.
Output voltage parameter: If its output voltage is a constant value, it is a constant voltage power supply. If it is a range value, it is a constant current power supply.
For example, the label of the power supply shows that the output voltage is 24V, we can confirm that this is a constant voltage power supply. If it is 30-80V, then the power supply must be a constant current power supply.

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