- Fri Mar 08, 2019 4:02 pm
#80980
That's the approach I have ended up with - after going through a 'common' LDO in my first design, to a really low quiescent current LDO, I now use a buck/boost to get as much as I can out of the battery.
However, I've been doing even more digging and there are three factors that may cause me to go back to the second choice of a nice LDO:
- the buck/boost and added components is quite a bit more expensive
- the rechargeable battery holds its voltage and current well but drops really quickly at the end of its charge. This means that the boost doesn't give you much more time for all that added cost and complexity
- the ESP8266 will actually still run OK on voltages < 3.3V. In fact it goes down quite a bit lower than that. If my external sensors are also as tolerant (and most are actually 1.8V) then I may be overcomplicating my circuit for almost no gain, especially in light of point 2
eriksl wrote:Caio.Viana wrote:thanks for the tips, I will opt for the linear regulator because the activations are not frequent and the low current consumption without load of the regulator
I think if you'd use a combined converter (buck/boost, they're actually two circuits combined into one), you'd be able to use the ESP8266 until the battery is really empty. The buck/boost converter would step down the voltage if it's too high and step it up if it's too low. You could configure it to always convert to 5 V and then add a linear converter to 3.3 V, which would make your power supply rock solid (and the ESP8266 needs that always run without any problems).
That's the approach I have ended up with - after going through a 'common' LDO in my first design, to a really low quiescent current LDO, I now use a buck/boost to get as much as I can out of the battery.
However, I've been doing even more digging and there are three factors that may cause me to go back to the second choice of a nice LDO:
- the buck/boost and added components is quite a bit more expensive
- the rechargeable battery holds its voltage and current well but drops really quickly at the end of its charge. This means that the boost doesn't give you much more time for all that added cost and complexity
- the ESP8266 will actually still run OK on voltages < 3.3V. In fact it goes down quite a bit lower than that. If my external sensors are also as tolerant (and most are actually 1.8V) then I may be overcomplicating my circuit for almost no gain, especially in light of point 2
