How to distinguish LED switching power supply is constant current and constant voltage?
We get a switching power supply to judge whether it is a constant current source or constant voltage source, we can first look at the parameters of the switching power supply, generally in the switching power supply above the logo, generally switching power supply above the input power, voltage, current and output power, voltage, current and other corresponding parameters, but also in the power supply on the marked constant voltage or constant current.
If in the practical application of the logo above can not see how we distinguish between the power supply is a constant voltage source or constant current source, we can actually measure, we take the market above the 60W12V5A power supply as an example, if the source is a constant current source, we add a 120W load at the output of the power supply, at this time, its output we measured the current is still 5A, but its voltage will drop to 6V, if We load the load at this time for 30W, the output current is 5A, its output voltage is 24V, our switching power supply will be with the change of the load current constant voltage changes, if it is a constant voltage source is with the change of the load, the voltage is unchanged, while the current changes.
So how does the switching power supply achieve constant voltage and constant current? In fact, this has to do with the circuit within the sampling feedback circuit, if the switching transformer is a constant current, then the sampling circuit in the switching power supply must be sampling current, if the switching power supply is a constant current, then the output sampling is generally sampling voltage.
Now most of the power supply is a constant voltage power supply, constant current power supply is relatively less, we choose what kind of switching power supply according to the specific circuit to analyse and the back of the need to bring the The load to determine. The high voltage requirements of the choice of constant voltage source, the high current requirements of the choice of constant current source.
