LMR14030: LMR14030 simualtion results not satisfactory.

Sunilkumar Subash

Prodigy 180 points

Part Number: LMR14030
Other Parts Discussed in Thread: LM2674, LMR14006, TPS560430

My input specifications are.

1. Generate a 5V +/- 3% output voltage ; output ripple~50mV or less if deemed necessary

2. Nominal operating range 9-16V

3. Output current ~200mA

4. Switching frequency: Around 500 kHz – you can increase the Fsw up to~2MHz if the components needed for lower Fsw are too big.

For the above requirement i designed the inductor and capacitor values as 85uh and 4.7uf.But with these values i am not getting the continous inductor current cylces.

over 5 years ago

0 Jason Wang (BSR-MV) over 5 years ago

TI__Genius 9550 points

hi,

I will calculate the value and give you feedback on Monday.

What is output current when you test?

Do you try to increase Fsw ?

0 Sunilkumar Subash over 5 years ago in reply to Jason Wang (BSR-MV)

Prodigy 180 points

Hi

The output current was 200mA with 25ohm load.

No i not checked with changing the frequency.

0 Sunilkumar Subash over 5 years ago

Prodigy 180 points

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Sunilkumar,

have you checked Webbench? It recommends a different circuitry for your application.

Also, your 200mA Schottky diode BAT54 is too weak for this switcher.

Kai

0 Sunilkumar Subash over 5 years ago in reply to kai klaas69

Prodigy 180 points

Hi

Ya i checked the webbench,i need to use exactly all components and need to simulate.

thank you

0 Sunilkumar Subash over 5 years ago

Prodigy 180 points

Could any one suggest me the short circuit protection for the above circuit.

0 kai klaas69 over 5 years ago in reply to Sunilkumar Subash

Guru 140200 points

Hi Sunilkumar,

the LMR14030 is short circuit protected. See section 8.3.9 of datasheet.

Kai

0 Sunilkumar Subash over 5 years ago in reply to kai klaas69

Prodigy 180 points

hi kai

You are right,from electrical characteristics,it is given that it will limit the current when current reaches minumum of 4.4 ampere.
But in my appliaction i need to design the short circuit protection for 1A.So i am asking is there any circuit which will help to achieve this.

0 kai klaas69 over 5 years ago in reply to Sunilkumar Subash

Guru 140200 points

Hi Sunilkumar,

if your maximum load current is only 200mA then I would take a switcher with a much lower maximum output current. Why not taking a 0.5A switcher?

Kai