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3.3 power supply schematic - need input before I place order

PostPosted: Sun Mar 25, 2018 10:20 am
by Vijay Gill
Hi,

I have just started using ESP8266 and ESP32 and I like both. For development purposes I am using USB cable and everything is fine. But now I want to start putting things together so that they can be used all around the house. The main issue is the power supply. After having gone through like nearly 20-30 blogs / forum-posts I have an idea in my mind put down in the form of the schematic (attached).

In brief:
1. It uses MCP1826. VccIn is 3.7V from Lipo battery.
2. ATtiny85 is optional but can be used to switch on/off the power supply (regular intervals or controlled by P2) so that quiescent current is kept to the minimum. If ATtiny is not used, JP2 can be used to set the SHDN pin of MCP1826 permanently high.
3. P2 is just for future use (like I could use for external things signalling ATtiny to switch on the supply. Or by just using jumpers it can be used to determine wake-up frequency (I am going to use this in my first project).

If all goes well, I will be placing order of manufacture of the PCB's (of course after the breadboard phase succeeds).

Please add your comments so that final product can be usable for more than one person (me :) ).

Vij

Re: 3.3 power supply schematic - need input before I place o

PostPosted: Sun Mar 25, 2018 7:12 pm
by rudy
Go look at the data sheet for the regulator. Look at what it says for input and output capacitors. I didn't see an input capacitor to the regulator in your schematic.

I don't understand how this will be supplying a ESP device. Obviously it will be on another board. While your schematic could be ok please remember that how you implement the schematic on the board can provide good or bad results.

Re: 3.3 power supply schematic - need input before I place o

PostPosted: Sun Mar 25, 2018 8:00 pm
by Vijay Gill
Hi Rudy,

Thanks for your contribution. My bad, I forgot to add that input capacitor. I just had a look at the datasheet.

Yes I am trying to make a generic board that I will use with esp8266 and esp32 boards all around the house. My idea is to add voltage level detection also to this supply so that the devices can notify their voltage level also. Then I will just replace the batteries with fully charged ones. But I am taking one step at a time along with learning about ESP boards.

Thanks is again.

Vij

Re: 3.3 power supply schematic - need input before I place o

PostPosted: Mon Mar 26, 2018 5:14 am
by Vijay Gill
Hi all,

Made changes after Rudy pointed out the mistakes. I've added capacitor before the regulator.

Schematic_3.3V-Power-Supply-using-LiPo-battery_Schematic_20180326111010.png


Thanks
Vijay