Help, after the load power supply has been working for a period of time, the microcontroller will shut down automatically

胡一刀123

Help, after the load power supply has been working for a period of time, the microcontroller will shut down automatically [Copy link]

The load is an ozone generator 3.7V, the working current is 400ma, and the battery power supply is 3.7V 2500MAH controlled by the Pmos switch . During use, it is found that after the ozone module works, there is a probability that the control board single chip will shut down, no output, and the restart button is required. The following is the schematic diagram. Pmos uses AO3407. I can't find any problems. Please ask the master to see if there is a device with unblocked value.

qwqwqw2088

1. How much power does the ozone module have after it is working? The battery should be able to drive it. Does the battery have a protection circuit? Is there overcurrent protection?

2. Whether the module interferes with the operation of the MCU after it is working, test the restart of the system away from and close to the MCU

胡一刀123

qwqwqw2088 Published on 2020-6-26 22:13 1. How much power does the ozone module have after it works? The battery should be able to drive it. Does the battery have a protection circuit? Is there over-current protection? 2. Is the module dry after it works?

1. The maximum power of the module is 1.5W, the battery can drive it, there is a protection board, and the overcurrent protection is 1A

2. Try it tomorrow

mingplus

If there is a large capacitor at the input of the ozone module , Q1 will have a large inrush current at the moment of turn-on , which may cause the battery voltage to be low enough to shut down the microcontroller . You can try adding a soft-start to Q1 ( connect a capacitor to Q1 S & G in parallel, and then connect a resistor from Q1 G to Q2 C in series).

maychang

"After the ozone module is working, there is a probability that the control board MCU will shut down and there will be no output. The reset button is required."

What does "MCU is off" mean? Are the LEDs lit or not? Is Q2 on or off?

maychang

"MCU shuts down" may not be entirely a hardware problem. It may be a software problem or a software problem caused by improper hardware.

胡一刀123

maychang posted on 2020-6-27 10:08 "After the ozone module works, there is a probability that the control board MCU will shut down, no output, and a restart button is required" "The MCU will shut down&rd ...

The phenomenon is: all LEDs are off, Q2 is turned off. Today I tested the microcontroller power supply. When the fault occurred, the voltage line did not change, but Q2 was indeed turned off, so I also suspected that it was a software problem.

maychang

Hu Yidao 123 posted on 2020-6-27 18:20 The phenomenon is: all LEDs are off, Q2 is turned off, today I tested the microcontroller power supply, when the fault occurred, the voltage line did not change, but Q2 was indeed turned off...

The work of this microcontroller is to measure the voltage at 3.7V by AD, and then display the voltage by four LEDs after comparison. As for controlling Q1, I don't know what quantity controls it (it may be timing or the voltage at 3.7V).

"The microcontroller is turned off" may be caused by external interference, or the power supply voltage may be reduced for a short time but not reduced to zero, causing the program to "run away".

maychang

Hu Yidao 123 posted on 2020-6-27 18:20 The phenomenon is: all LEDs are off, Q2 is turned off, today I tested the microcontroller power supply, when the fault occurred, the voltage line did not change, but Q2 was indeed turned off...

I don't know if your microcontroller has a "watchdog" inside. If it does, you may not have turned it on. If not, it is not difficult to set up a software "watchdog". Because your microcontroller still has several unused lines. Use an unused line and add a digital circuit chip such as 74HC14 or 555 to form a "watchdog". After the program runs away, the "watchdog" will automatically reset the microcontroller and continue to work.

maychang

Hu Yidao 123 posted on 2020-6-27 18:20 The phenomenon is: all LEDs are off, Q2 is turned off, today I tested the microcontroller power supply, when the fault occurred, the voltage line did not change, but Q2 was indeed turned off...

Of course, using a "watchdog" is only a remedial measure. The fundamental solution is to find out the cause of the microcontroller crash.

chunyang

The ozone generator has high-voltage discharge and heavy electromagnetic radiation interference, and also has an impact on the transient fluctuations of the power supply voltage. Both of these aspects may cause the MCU to malfunction, so it is mainly necessary to work hard on power supply design and anti-EMI design.