Buck design using mosfet switch

Sunilkumar Subash

Prodigy 180 points

Hello all

In one of my application i need to design the buck regulator circuit with the following specification

1.Input voltage 12V

2.Output voltage 5V

3.ouput ripple voltage 50mV

4.Load current 200mA

5 switching frequency 2Mhz.

Any other parameters from the microcontroller to driver circuit could be assumed.

I need to design the buck converter using mosfet switch,please any one guide me on the design of mosfet driver circuit,also gate resistor calculation for the mosfet.

over 5 years ago

0 Matt Schurmann over 5 years ago

TI__Genius 11095 points

For this power level, I suggest to look at the TI's Webench designer for device suggestions. I think a microcontroller with external FET is probably not an optimal solution based on what you have described.

https://webench.ti.com/power-designer/switching-regulator/

0 Sunilkumar Subash over 5 years ago in reply to Matt Schurmann

Prodigy 180 points

Hello matt

why external mosfet switch option is not good here instead of IC switch.

0 Matt Schurmann over 5 years ago in reply to Sunilkumar Subash

TI__Genius 11095 points

From a cost and performance perspective.

0- I assume you are re-using an MCU elsewhere in your system. I'm sure the integrated devices or controller+FET suggested by Webench would be less expensive than an MCU for a power supply. Plus, these devices are designed for power supply applications, and you would not need to develop code.

1- You will still need to use a gate driver of some kind to interface with a MCU. This may be an IC, or it may be discrete implementation. Based on the power level, I think a (half bridge) buck topology will be OK.

2- What are your requirements in terms of load transient regulation? You have a DC regulation spec, so I assume the converter will need to be regulated. MCU control will generally be very slow.

Power management

Power management forum

Buck design using mosfet switch