How do I calculate the battery life of ESP8266-based products?
Does anyone share the considerations for calculating the battery life of ESP8266-based products? Does LDO consume current? if yes which LDO and battery is advisable to use? @Hardware Integration
21 Replies
Yes, LDO consumes current
You can use RT9013 3.3 V LDO
An
LDO doesn't really "consume" current. The current going in at the entrance is the same current that leaves the exit of the LDO. It just brings the voltage down (eg. from 5V to 3V3) and turns the surplus energy into heat.
A switched voltage converter would be more efficient. It can bring the voltage down, while preserving the ingoing energy. For example: a 1A going in at 5V could then theoretically result in a 1.5A at 3V3 at the exit (if efficiency would be 100%, which is of course impossible).
So the efficiency of a switched voltage converter is considerably higher compared to an LDO. However, the downside is that it injects noise in your circuit.Thank you @RR Let me check the datasheet
Depends on code execution time, sleep time
LDOs drop power,infact it depends on who much current is drawn. If V1 is input voltage and V2 is output, the power loss is (V1-V2) x I + (V1 x Iquiscent)
so LDOs suit apps drawing low current and lower voltage drop band.
This calculated, you can arrive at the battery life adding MCU power consumption(very dynamic depending on power modes, peripherals used etc). Common one is LM1117 and they come in both fixed and adjustable versions.
@Navadeep , yes. Each device has its quiescent current, otherwise it would not work. Efficiency of switching mode converters is sometimes hard to calculate because the efficiency does not depend only on input and output voltages and currents but the big portion of it are switching losses and conduction losses in inductors.
The situation must be considered individually and based on measurement all the time.
True, Petr. But LDO's loss is straight right? It's drop is linearly proportional to the in/out voltage level and current.
Yes, it is.
I aggree with that you wrote.
I just reacted on the previous comments.
This is what describes the efficiency of a typical LDO (V1-V2) x I + (V1 x Iquiscent). As you correctly wrote.
This guy looks promising 👻
https://www.st.com/en/power-management/stlq020.html
@Umesh Lokhande you might want to try this out for you IoT designs.
My cursor goes to 'buy free sample'. Do anyone have experience getting samples form ST?
If you are designing a product you can get first few free samples from st website. Official email id required.
Many vendors had same policy including TI, digikey
Oh, well. I had tried most others in 2020/2021. ST didn't work out I remember. They rejected my sample request for STM32F303 MCU. Oh, by the way I have a list - will share,
https://docs.google.com/document/d/1Yb828TpndOA_jOLzlhR7l8-WQbaxUj8Vf9b-Ge7XZKk/edit?usp=sharing
Compiled this 2 yrs ago. Do comment if you think something is worth to be added here.
Google Docs
Maker Stuff Resource Sheet
Umesh, I did a lot of work on low power design and IQ of DC DC and LDO. LDO consumes a lot of power when running. DC DC with low IQ are the best in 99% of the cases. If you have sensitive RF or analog sensing, you might want to use LDO to keep noise floor really low, but for everything else dc dc are much better
if you have time, please go through the tests I have done and shared results here: https://pallavaggarwal.in/2021/04/10/low-power-embedded-system-iq/
Pallav Aggarwal
IQ Of Power Supply In Low Power Embedded System Design
The quiescent current of the power supply needs to be as low as possible if you are working on a low power embedded system design.
you will be surprised