Product Description: Soft Power Switch - SparkFun SPX-17870
A soft powerswitchthat works in a similar way to the button on a laptop. One press will turn the system on, a sequence of presses can turn the system off, and in the event of anemergency, pressing and holding the button will allow foran emergency power disconnect. This is an ideal board for projects using battery power. The Sense / Control pin allows you to read the current state of the switch. The board is equipped with twoJSTconnectors for battery connection, the module is also equipped withLi-Polbattery charger circuit. There is also additional pin on the board, which allows you to read current consumption by the system. It works with voltage up to 12 V. It is equipped with a 3.3 V diode to protect the system from overvoltage.
The soft power switch is an experimental product from the SparX series. These are advanced solutions that do not go into regular production. They are created in very small quantities. They are tested by SparkFun but do not have its technical support.
Example of module usage
The most common use case is more or less like this:
- The microcontroller starts executing code and checks if the power button is still pressed for X milliseconds.
- If not, just tap it, go to sleep.
- If yes, turn it on and run a normal program.
- The user presses the power button in the normal program.
- If the power button is pressed for
- If the power button is pressed for >X milliseconds, it's time to shut down.
The module has a defect in the 22 uF capacitor used, which requires an override time of 13 seconds. Under normal conditions, the system will turn on as fast as it is specified in the code, so the problem should not arise, but there may be a problem with the long turn-off time of 13 seconds. By using an external button, this problem is completely eliminated.
Specification of soft power switch module
- Operating voltage: up to 12 V
- Maximum load: 4 A
- Current consumption: up to 50 nA
- Power status monitoring
- Two JST 2.0 connectors for battery connection
- Built-in Li-Pol battery charger