Issue with powering ESP32 Dev Module with 5V regulator(7805) from 12V power supply

Other Hardware General Electronics
21

It is just the way the photo has been taken, it one electro capacitor and a ceramic one the output. The other electro is on the input.

Yes I have done what you suggested I moved the amplifiers onto the regulators gnds.

I am redrawing the circuit by hand right now.

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22

Probably a shipload radiates from the speaker wires of the filterless class-D amplifier.
A 5volt/330kHz square wave. Keep them wires short.
Leo..

23

But note #15. :grin:

24
  1. small bypass cap should be on the input of 7805 reg, Not output (look at the datasheet of the chip for more information...)
  2. try at least 1000uF as regulator output cap. ESP32 has "high" current peaks, up tp 300mA so you need low impedance power supply to work correctly.
  3. Use separate voltage regulator for the amps it`s cheep, no need to make compromises here and make unneeded problems..
    Cheers!
25

My five cents: do you have a heat sink on the 7805?
(how large: for 4 W at least?)

Drawing 300 mA (for MCU) with a voltage drop from 12V down to 5V - gives you 7V *0.3A = 2.1W burned power. It is a lot.
Without a proper heat sink - the 7805 will enter immediately the thermal protection (and shuts down).

BTW:
You try to power audio amplifiers from the 3V3 rail, provided by your MCU module?
Are you sure they can provide so much current? (they had to power the MCU - nothing else, but now also so much current for the audio power amps?).

Just take your 7805, powered by 12V, put just a 10 Ohm load resistor on it (on 5V out, instead of MCU), but as a 3.5 .. 5W type (!!) and see if voltage remains stable.

It tries to draw 0.5A from 7805. I assume - 7805 gets so hot ... (and shuts down immediately).

26

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27

The 7805 is now seeing the arduino, TFT and two "3W" class D amplifiers with 4 ohm loads.

Well, start by disconnecting the supply to the amplifiers anyway.

Your schematic doesnt show the values of the smoothing capacitors?

28

I have changed the capacitors for the regulator so it is 470uF on the input and 1000uF on the output as well as 0.1uF ceramic.

I have also tried disconnecting everything and just tried powering the board, but it is not drawing enough current. I am starting to think it might be a faulty regulator but it is weird that it still regulates the voltage correctly.

I have also tried with a 9V power supply, but the same problem still persists.

Are the smoothing/crossover capacitors the ones connected from the amp to the speaker, because if so they are not connected yet but they are going to 2.2uF.

29

Hi jarrod_w,

Your sketched-out circuit diagram shown in post #21 shows the 7805 has been left without a GND 0v connection!

Can you confirm that the center pin / Tab of the 7805 is connected to GND 0v?
As this could account for the issues you are experiencing!

HTH?

30

Okay this where my inexperience comes in, what/where would the GND 0V connection be?

31

The battery - should also be connected to the center pin of the 7805 voltage regulator.

HTH?

32

I just realised my mistake in the sketch I just forgot to draw it in, in the actual circuit it is connected to GND

33

The 12v >1A thingy, how is 12V being connected to the ESP32?

What is the CAPII88?

Did the OP try a separate 7805 to just supply the Amps? Connect the grounds together.

34

The 12V is connect via a 5V regulator to the ESP32.

The CAP1188 is a Capacitive touch sensor.

Yep I did try all that.

35

Well that certainty clears that up. Thanks and good luck finding your issue.

36

I have brought a buck converter the Pololu 5V 1.5A ( S13V15F5) and the problem still occurs, still not drawing enough current.

37

Hi,

Please show us a diagram of it in your circuit.
Please include pin numbers and names, especially around the ESP32.
To what pin on the ESP32 do you have the 5V connected?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

38

This is a diagram of what is connected at the moment in the circuit.

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Another factor that I think might be apart of the issue is when measuring the voltage at the ESP32 it is bellow 5V, it is around 4.6V.

39

Hi,

What do you mean by "around"?
What is the voltage at the output of the DC-DC converter with the circuit connected?
What is your DMM?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

40

It fluctuates between 4.57V and 4.56V, just on my last reading on it.

On the output the reading is 4.99V.

The DMM I am using is a digitech QM1321.