12Volt to 5Volt converter

[Chassis]

Can someone please be so kind and explain to me what kind of electronic components exist inside a 12V cellphone car charger and what each one of them's job is.

I'm fitting a Car tracker,but want to use a normal cellphone charger to keep it constantly charged.

I just need to step-down from 12V to 5V.

The Gps Tracker TK102 has a normal re-chargeable 4.7V battery.

 

[AnalogKid]

Most car cell phone chargers have a simple non-isolated buck regulator, one of the standard switching power supply configurations. Usually it is a single chip with the voltage reference, switcher control circuits, and output transistor. This, plus a few external components and one inductor, is the entire circuit.

One of the most used parts for this is this:

http://www.onsemi.com/pub_link/Collateral/MC34063A-D.PDF

Page 7 has a typical buvk circuit, and page 11 has the design equations.

By the way, there is no way you can build this for less money than buying one and removing the circuit board from the cigarete lighter plug.

ak

 

[Chassis]

So you saying that I can use any cellphone car charger that puts out 5V and just change the input pluck,the circuit board should be the same hey? And is there something like over charging the unit? What's the purpose for the black ic on the board?

 

[davenn]

So you saying that I can use any cellphone car charger that puts out 5V and just change the input pluck,the circuit board should be the same hey?

yes, its just a 5V supply

And is there something like over charging the unit?

the actual charging control is 99.99% of the time done inside the device ... GPS unit, cellphone or whatever

What's the purpose for the black ic on the board?

it's the switching regulator chip



Dave

 

[Chassis]

It works brilliant,thanks for all the answers guys.

 

[davenn]

good to hear