Speaking of isolated power supply and non-isolated power supply, at this time, there must be a high voltage AC and low voltage DC in the power supply, and the high voltage AC and low voltage DC of the isolated power supply are completely separated.
isolated power supply
The isolated power supply generally uses a transformer design, and the live line (L) and neutral line (N) of high-voltage AC are disconnected from the VCC and ground (GND) of low-voltage DC. It is safe to touch the low-voltage part of the circuit. As can be seen from the design schematic of the isolated power supply, the left high-voltage part and the right low-voltage part are completely separated.
non-isolated power
Non-isolated power supplies generally cost less, do not use transformer design, high voltage AC live line (L) and neutral line (N) and low voltage DC VCC and ground (GND) have one end is connected together. When people touch the low-voltage part of the circuit, they may feel a slight electric shock. Of course, the use of non-isolated power supply design products are also protected by the shell, will not let the user touch the circuit board, but also can be safely used. As can be seen from the schematic diagram of the non-isolated power supply, one end of the high voltage part on the left is connected with one end of the low voltage part on the right.
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The isolated power supply is an electric-magnetic-electrical conversion, the output side is not connected to the earth (input side), the input and output side of the components are also physically separated, that is, the input side (AC or DC) and the output side of the positive and negative poles can not form a loop. Separate loop on output side. Isolated power supply is relatively safe, if the isolated output side of the high voltage also form a loop (for people) is also very dangerous.
The isolated power supply uses a transformer to reduce the 220V voltage to a lower voltage through the transformer, and then recirculates it into a direct current output power supply. Because the main coil of the transformer bears 220V voltage, the secondary coil only bears the low AC voltage of the output, and the primary and secondary coils are not directly connected, so it is called the isolated power supply.
difference
One, isolate the power supply
1: The advantage of the isolated power supply is that it will not pose a threat to the human body, and the wide voltage performance is very good.
2: Isolated drive is safe but less efficient.
3: In terms of circuit structure: the current isolation scheme is mostly AC\/DC Flyback circuit scheme, so the relative circuit is more complex and the cost is higher.
Two, non-isolated power supply
1: The non-isolated is now very mature, the voltage range is slightly worse than the isolated, the voltage range is between 110V-300V, and the isolated power supply can do 60-300V
2: Non-isolated drive efficiency is higher, should be according to the requirements of actual use to choose isolated or non-isolated drive.
3: Non-isolated type is basically the use of DC\/DC Boost or Buck circuit, it is relatively simple circuit, so the cost is relatively low.