There are lots of examples of latching circuits that use a single momentary push-button to turn on/off a circuit by combining two or more transistors. Some examples are:
- Simple soft power latching circuit for a microcontroller
Since it is common for LiPo-powered devices use an LDO to generate a constant 3.3 V, my question is: can you use the "ENABLE" pin on the LDO to generate that latch from the microcontroller? The general idea would be something like:
- Push button pulls AP2112 LDO EN high
- LDO powers microcontroller
- Microcontroller uses LATCH pin to keep LDO EN pin high (this is the latch)
- Microcontroller can shut-down the whole system when desired by setting LATCH LOW
Do you spot any problems/disadvantages with this approach? It is a very common application and I am surprised I haven't found anything similar on the internet.