Boost converter to 5V for gyroscopic camera mount

[RR27]

Hi everyone,

I am builiding an ATmega328p based gyroscopic camera mount, I made the first prototype, wrote and uploaded the program through Arduino, but now i am going to get rid of the board. Part of my PCB is ready, I miss the voltage regulator. At the beginning I was thinking about a linear regulator, but I discovered that a buck converter is more efficient, and I need efficiency because the mount will be powered by Li-po or Li-Ion battery.

I need to power the ATmega, a servo and the accelerometer and gyroscope module (MPU-6050). I thought that Gopro battery could be great, in fact I can use an external charger/controller/ecc. without put all the charging control circuit on my PCB. This batteries are 3.7V and 1160mAh. So I need a step-up regulator.

I found this one https://www.ebay.com/itm/mini-dc-dc...t-Module-for-Breadboard-Arduino-/271734570473

I would like to integrate it on my pcb but I do not know how it is made, I can see a 22uH inductance, an SS12 diode, two ???F capacitor and another device.


I wonder if someone could help me with the scheme/design of this circuit and suggest me the capacitance of the two capacitors and the model of the other device which I think is a voltage regulator (?).


I have just started mecahnical engineering and I am new in the electronic world and I would like to learn a lot about it, I am italian and I hope my english is good enough to make you understand me.

I thank you in advance for your help


Roberto

 

[BradtheRad]

For step-up you want a boost converter. (A buck type steps down.)

Do you intend to construct your own? See my posts in the thread below. They contain links to simulations of buck, boost, and buckboost converters. The simulations are animated and interactive. (It needs for your computer to have Java installed.)

https://www.edaboard.com/threads/268178/

22uH inductance, an SS12 diode, two ???F capacitor

A usable capacitor value is often in the range of 2-50 times the inductor value.

If you design your own smps, 20 kHz is a manageable switching frequency.

------------------------

As an alternate, consider trying a simple voltage doubler. A 555 timer IC can drive it, but the 555 can only provide 200 mA, so it is only for small loads. If you need more power then you can add a half-bridge, and larger capacitors, etc.



The low ohm resistors are unnecessary. One limits 555 output. The other helps illustrates use of a supply input capacitor, because the voltage doubler sends current back to the power supply without it.

 

[RR27]

Yes, I am sorry... Boost converter.

Thank you very much for your answers, so the two capacitors would be 44-1100 uF right? I would like to integrate this circuit to my PCB but I don't know what is the model of that device (is that a frequency regulator?). It has to be 20kHz? If you can help me to find out this device and the precise scheme I think i could be ready to reproduce it.


I looked at your link and I've also found another thread in which you posted this scheme https://obrazki.elektroda.pl/1552451000_1372332855.png that would be right for me, I think. I am not sure on the value of the resistors: 2 X 100Ohm and 1 X 10Ohm, and what frequency regulator do I have to use?


I don't think that the NE555 could completely fit my project, in fact 200mA is probably too little, but I will remember this suggestion

Thank you very much for your patience


Roberto

 

[BradtheRad]

so the two capacitors would be 44-1100 uF right?

The greater the output current, the larger smoothing capacitor is needed.

what is the model of that device (is that a frequency regulator?). It has to be 20kHz? If you can help me to find out this device and the precise scheme I think i could be ready to reproduce it.

Any pulse generator will do the job, as long as it produces a waveform which is at the correct voltage which can turn the transistor/mosfet fully on and fully off.

I looked at your link and I've also found another thread in which you posted this scheme https://obrazki.elektroda.pl/1552451000_1372332855.png that would be right for me, I think. I am not sure on the value of the resistors: 2 X 100Ohm and 1 X 10Ohm, and what frequency regulator do I have to use?

The resistors are a fraction of an ohm. They are there to represent unknown resistances in a real hardware circuit. The total might add up to an ohm or more. If it is too high, it can prevent you from getting full voltage from your converter.

You must adjust the control frequency, and duty cycle, so it cooperates with characteristics of your inductor. It is easy to use a small inductor, but then you must switch it at a fast frequency, and possibly use fast-recovery diodes.

I believe you can purchase a manufactured module of an adjustable boost converter, if you decide not to make your own.

 

[treez]

Here is a 3.7V to 5V boost converter in free download ltspice simulation. You can experiment with it if you wish

 

[RR27]

Thank you very much BradtheRad and treez, but I don't know how to use Boost.txt... Can you help me?

 

[BradtheRad]

Boost.txt is a netlist, a common format of the Spice family of electronic circuit simulators.

LTSpice is one of these. You can download and use it free. It has frequent recommendations at this forum.

https://www.linear.com/designtools/software/

After you install LTSpice on your computer:

a) Click on Boost.txt (post #5) to download it.

b) Rename it to Boost.asc.

c) Examine its properties. Its icon should resemble a transistor symbol. The file may appear as an LTspice file, or, you may need to adjust its properties so it becomes an LTspice file. Make certain the file extension is visible and appears as 'asc'.

d) Load it into LTspice. It should appear onscreen as a schematic.

e) Choose menu command Simulate>>Run. (The 'running man' icon)

f) If the run is free of errors, then you can view scope traces. Select Visible Traces (Right-click on the schematic). This opens a scope window.

g) Right-click and select Visible Traces. Choose voltage, current, from the window. (Example, output voltage is V(n003).)

The above steps worked for me just now.