How to select PCB isolated power supply

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How to select PCB isolated power supply [Copy link]

These are my three PCB power supply options. Blue 1 and blue 2 are isolated power modules, the green one is the MCU control circuit, and the yellow one is the IO input/output circuit.

Solution 1: Blue 1 and Blue 2 are powered separately, but the user may only have one power supply, and the two grounds are still not separated.

Solution 2: Blue 1, the power supply for the entire device is connected to the MCU, and the IO port is isolated from the main circuit. If the IO is under heavy load, the cost may increase, but the advantage is that IO problems will not affect the MCU circuit.

Solution 3: Blue 1, the power supply for the entire device is connected to the IO, and the MCU is isolated from the main circuit. This problem is that the IO problem will affect the MCU circuit

Dear colleagues, which kind of power supply do you prefer?

qwqwqw2088

If the control requirements are high, the third option is preferred, with isolation.

In fact, the specific circuit needs to be analyzed, such as whether the power supply ripple is serious, etc.

MCU circuit, if the power supply has a design defect, the program will run out of control, which is normal

Gen_X

In principle, choose option B.

The reason is simple, it is more about perception and processing of the outside world - that is, it can be controlled or controlled.

Solution C affects the operation of the MPU when IO fails, which means that the current "state" may be out of control.