help for 12V to 5V regulator design

12v to 5v regulator

Dear all,

If someone can give me any suggestion about how to start in design a 12V to 5V regulator design (output current : 300mA max)?
My boss give me the topic , but I don't have any idea in this region .
So can you give any comment to design this circuit?
Thanks a lot for any response.

12v to 5v 1a

Hi !

The simplest way to do this is using a linear voltage regulator as 7805 (from National/Motorola/Fairchild etc) device. It will regulate the output voltage to 5V @1A. This device has only 3 terminals (Vin, GND and Vout) and needs only a bypass capacitor in output (100nF).
Another option is the LM317 (adjustable regulator), also for 1A, but you need more 2 resistors and the capacitor.

These linear regulators waste power, because they convert the difference betwenn output voltage and input voltage (multiplied by the current) into heat, so maybe necessary to use a heatsink attached to the regulator. Efficiency in this case will be 41%.

To get a more efficient regulator, you can use a DC-DC converter using for example the LM2576-5.0 (a siwitching step down regulator) that converts the 12V input voltage to 5V using a inductor, a fast diode and a filter capacitor. It has a much better efficiency - around 75 to 80%.

There other ways and devices, but these are common and simple.

12v 5v regulator

For your current needs 300mA the best choice (simpler design and construction) is the use of the 7805 regulator. You must consider the use of a small heatsing for the IC, a small piece of alluminium is sufficient.

12v to 5v switching regulator

what are the requirements? like load reg, line reg, vin range?...
i am surprised to hear that your boss trust u enough to ask u to handle something u have no idea of. Really surprised... r u in the industry?

12v to 5v

hai,
You can also use a basic zener diode regulator
In the fallowing ckt,You can use a IN5338B a 5V,5W zener diode along with a 22R,5W series resister alltoghther can give upto 900mA of output current . Check the datasheet of IN5338B for more details. Just stick a smoothing capacitor at the output for stable output.

12v to 5v voltage regulator

Hi

I show you a switching regulator that is fine for your job:
LM2575-5V for 5v output (1A) and a varying input range, LM3575-Adj
for variable output.

datasheets are appended.

masoud

12 to 5v regulator

Thank your response.
And If we need to design the circuit integrated to chip
can we use the normal process like TSMC 0.25um process ? Or we need a special process ?
Because th input voltage can vary from 7V to 40V .

5v regulator circuit

you need special high voltage process, not normal process for logics..
and it's going to cost more