How to turn off the power supply?

fish001

How to turn off the power supply? [Copy link]

I looked at the questions for the Shandong Electric Competition last year.
There is a part that
requires 430 to automatically cut off the power supply and then...
(1) Add an "auto-off" function, that is, in the measurement mode, if no key is pressed within 1 minute,
the meter will automatically turn off the power supply and enter a low power state; if any key is pressed again, the meter will automatically return to the state before "auto-off".

How to achieve it!!!

qwqwqw2088

Save parameters before entering low power mode

chunyang

This requires the cooperation of hardware and software. In terms of software, when no key operation is detected for a period of time, the scene is saved first, then the power is turned off, and then the low-power sleep state instruction is executed by the capacitor in the circuit. In terms of hardware, all buttons that support wake-up require a logic summary, that is, when the button is pressed, an edge jump will be generated, and this edge jump will be used to temporarily wake up the power supply and MCU. The MCU then enables the power supply and restores the state before the previous sleep state according to the previously saved scene parameters. To avoid power consumption of the logic summary circuit, a double-pole key switch or a diode can be used for isolation. If the power supply is a regulated voltage, a model with an enable terminal must be used, or a soft switch must be built with a MOS tube.

alan000345

You'll need a relay.

乐在其中1100

I don't understand it, but I know that many digital multimeters now use this solution.