When doing a circuit design, using a 9~24V power supply to power a device, it is necessary to realize the function of powering off the device three minutes after manual startup. Use an STM32 IO port as a switch. How to realize this switch drive using mos tube or optocoupler? The current of the device is 400mA at 12V. Ask everyone. Thank you
Frank Posted on February 23, 2021
It is recommended to use P MOS transistors. Generally speaking, optocouplers are mostly used for signal devices to isolate interference and the like, so it is better to use P-type MOS transistors for switch drive. N-type MOS transistors are used in an environment with a voltage of about 5V, generally more than 12V. It is recommended to use P-type MOS transistors. Of course, this is mainly a cost issue. If you are not short of money, you can choose whatever you want. If you use a P-type MOS tube, connect the MOS tube to the positive pole of the power supply and equipment, and then use a small The triode drives the MOS tube, and the link method is from the chip IO port to the triode to the MOS tube to the device.
Lacey Posted on February 23, 2021
Use a MOS tube to form a common source circuit, the IO port of the microcontroller controls the gate of the MOS tube, and then pay attention to the withstand voltage and Id of the MOS tube.
Xander Posted on February 23, 2021
A triode should be used to drive the MOS tube. The supply voltage of the microcontroller is generally less than the driving voltage of the MOS tube.