How to select a switching power supply?
The first point of choosing switching power supply, clear their needs
Generally we are in their own use of the product failure will think of buying switching power supply, you can directly take the previous power supply to find some professional sales of switching power supply company, there is no such model or parameters with which to match the model can be replaced, the specific can be carried out from the following aspects:
Switching power supply input and output type
Can be roughly divided into: ① AC / DC ② DC / DC ③ DC / AC Note: AC for AC, DC for DC, such as AC / DC that is AC input DC output.
2 Input Voltage
Commonly used input voltage specifications are 110V, 220V, and universal input voltage (AC: 85V-264V) three specifications. Input voltage specifications should be selected according to the area of use.
3 Output voltage and current
Selection of switching power supply is firstly, the voltage should be the same, followed by the current, the rated current of the switching power supply must be greater than the maximum current of the load, for example, your circuit is 15V, 60mA, it is generally recommended to select the power supply of more than 100mA. In addition, as long as the voltage is the same, no matter how much greater the current provided by the switching power supply than the actual use of the circuit will only pass so much, there will be no damage.
4 Switching Power Supply Functions
① regulated switching power supply: input voltage output voltage are rated at a certain value; ② silicon controlled switching power supply: can be rectified by the input voltage to change the size of the output voltage; ③ adjustable switching power supply: input voltage rated range, the output voltage and current can be adjusted through the potentiometer and other ways.
5 Switching power supply load characteristics
In order to improve the reliability of the system, it is recommended that the switching power supply operating at 50% -80% load is good, that is, the choice of roughly more than 30% of the output power rated models. For example, if the power used is 20W, a switching power supply with an output power of 25W-40W should be used. If the load is a motor, light bulb or capacitive load, when the power-on moment when the current is large, should be selected to avoid overloading the power supply.
6 ambient temperature
Also need to consider the operating temperature of the switching power supply, and there is no additional auxiliary cooling equipment, in the high ring power supply needs to be derated output. The ambient temperature should be referred to the derating curve of the output power.
