Share a simple level conversion circuit design: 5V and 3.3V interchange

Converting a 5V power supply voltage to 3.3V, or converting 3.3V to 5V, is the level conversion we talked about before.

Today WeiBi shared a relatively simple level conversion circuit that he saw on the Internet.

 Use a MOS tube to connect, this is a 5V microcontroller, and this is a 3.3V PM2.5 sensor.

How to convert 3.3V with 5V?

When the microcontroller sends a high level to the right, the gate and source of the MOS tube in the circuit are 3.3V, which means that the level signal received by VB is a high level of 3.3V. This realizes the function of converting 5V to 3.3V.

What if the microcontroller sends a low level of 0V?

A diode is connected in parallel at both ends of the MOS tube, the anode is connected to a pull-up 3.3V resistor, and the cathode is connected to the 0V low level sent by VA. The diode will be turned on, and the voltage of VB will be pulled down from 3.3V to only about 0.7V, changing from the original high level to a low level.

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Next, let’s see how to convert 3.3V to 5V?

As before, when VB outputs 3.3V high level, the gate and source of the MOS tube are both 3.3V, the MOS tube is not turned on, and VA will get 5V from the pull-up resistor (R1), realizing the conversion of 3.3V on the left into 5V on the right.

When VB outputs a low level of 0V, the gate voltage of the MOS tube is 3.3V, the source voltage becomes 0V, the MOS tube will be turned on, and the VA voltage will be pulled down. At this time, VA is a low level of 0V, realizing the conversion of 0V on the left to 0V on the right.

This is the level conversion circuit I want to share today. It can be easily completed using a MOS tube and three pull-up resistors.