Powering ESP8266 from LM2575

I powered an ATMEGA 32a using LM2575 Switching regulator and is working fine and tested with blinky and other sketches.

As a next step I wanted to connect ESP8266 WiFi module (http://www.ebay.in/itm/281934775666). This module runs at 3.3v, so I used 1k and 2k resistor as a voltage divider to power ESP8266. Unfortunately ESP8266 is not getting switched on, I cant see the Red light showing in the module. If I connect directly to 5v then it works fine but getting heated up because of high voltage.

I used the above schema to regulate power from 12v to 5v. From the 5v I used the 1k and 2k resistor as voltage divider to power the ESP8266.

If this setup is wrong then what are all the options i have to power ESP8266. If possible from the 5v output from LM2575.

I read somewhere that the esp8266 can draw up to 300 mA at times. I don't think your resistor voltage divider scheme will deliver that.

raschemmel:
I read somewhere that the esp8266 can draw up to 300 mA at times. I don't think your resistor voltage divider scheme will deliver that.

Is it ok to connect LM1117 to the output of LM2575's 5 voltage?

Not unless it is rated for 5V.

Using 1 and 2 k as a divider you will be lucky to get 1 milliamp.

Using 1 ohm and 2 ohms might work but you would require a large current and have high heat losses.

You need a proper regulator for the 3.3V supply.

When I have connected my ESP's to my Arduino's..

I have a +3.3v powering the ESP..

and the only voltage divider I use if for the RX/TX line..

Seems to have worked fine so far..

I also read that in AP mode.. it will draw a lot more current. (not sure if this also applies to other modes?)

For a quick test with a ESP8266 module I used a couple of diode (1n4007) to drop the 5V to 3.5 V, and was working fine.

Cheers, Ale.

xl97:
When I have connected my ESP's to my Arduino's..

I have a +3.3v powering the ESP..

and the only voltage divider I use if for the RX/TX line..

Seems to have worked fine so far..

I also read that in AP mode.. it will draw a lot more current. (not sure if this also applies to other modes?)

I tried once connecting ESP to 3.3v of Arduino uno but it didnt worked for me. So for testing a sketch I connected to 5v for some time. Yes I used voltage divider for ESP RX.

Boardburner2:
Not unless it is rated for 5V.

Using 1 and 2 k as a divider you will be lucky to get 1 milliamp.

Using 1 ohm and 2 ohms might work but you would require a large current and have high heat losses.

You need a proper regulator for the 3.3V supply.

Will it work, if I connect a regulator like LM1117 3.3v fixed output to 5v output of LM2575

Alternative approach:
In my setup I have a HC-05 Bluetooth and ESP8266, I believe both can run with 3.3v. So I am thinking of powering the Atmega 32a using 3.3v using a LM2575 3.3v fixed output regulator. This way I dont have to use multiple regulators for 5v and 3.3v. Also I can avoid RXD level shifters to these modules.

Please correct me if I am wrong in my alternative approach.

You need a proper regulator for the 3.3V supply.

I can't help but wonder why this is isn't obvious.

ilguargua:
For a quick test with a ESP8266 module I used a couple of diode (1n4007) to drop the 5V to 3.5 V, and was working fine.

I will give it a try. If it works then it’s good for me. I dont have to buy any 3.3v regulators.

Just reposting my alternative approach to power Atmega32a and other modules.

In my setup I have a HC-05 Bluetooth and ESP8266, I believe both can run with 3.3v. So I am thinking of powering the Atmega 32a using 3.3v using a LM2575 3.3v fixed output regulator. This way I dont have to use multiple regulators for 5v and 3.3v. Also I can avoid RXD level shifters to these modules.

Please correct me if I am wrong in my alternative approach.

xl97:
and the only voltage divider I use if for the RX/TX line..

According to Adafruit, you need nothing more than one diode.

sarouje:
Just reposting my alternative approach to power Atmega32a and other modules.

In my setup I have a HC-05 Bluetooth and ESP8266, I believe both can run with 3.3v. So I am thinking of powering the Atmega 32a using 3.3v using a LM2575 3.3v fixed output regulator. This way I dont have to use multiple regulators for 5v and 3.3v. Also I can avoid RXD level shifters to these modules.

Please correct me if I am wrong in my alternative approach.

At wich frequency is the Atmega 32 running? Some chip can work at 3.3 but with limited frequency (eg. 8 mhz), check the datasheet.

Cheers, Ale.

ilguargua:
At wich frequency is the Atmega 32 running? Some chip can work at 3.3 but with limited frequency (eg. 8 mhz), check the datasheet.

Good point, I havent thought about that possibility. Currently Atmega 32 runs at 16mhz. If I run at 3.3v I will be overclocking the chip.

Thanks for notifying me.

I think i will use LM1117 to regulate power to 3.3v from 5v. It's drop out voltage is 1.2, so I think I can use it without much issues.