Hi,
1, How to select the operating frequency for any DC DC converter.?
2, What All parameters need to look at while selecting operating frequency ?
3, What is the impact on selecting the wrong operating frequency ?

Rgds,
Mahantesh

 

Hi,
1, How to select the operating frequency for any DC DC converter.?
2, What All parameters need to look at while selecting operating frequency ?
3, What is the impact on selecting the wrong operating frequency ?

Rgds,
Mahantesh

I can’t give you a complete answer but I can tell you that it’s a compromise. This is what engineering is about, finding a design that balances competing factors.

A higher frequency allows using smaller components for storing energy, inductors in this case. But the design challenge becomes increasingly more difficult with frequency. 10kHz might be easy while 10MHz is very difficult.

The design process is iterative. Pick a set of specifications you want to meet, select a topology, start simulating and choosing components, find out how high you can go with real components.

While you’re doing all this, keep in mind that it’s all been done already by experts and can be purchased for next to nothing on EBay.

 

Hi,
1, How to select the operating frequency for any DC DC converter.?
2, What All parameters need to look at while selecting operating frequency ?
3, What is the impact on selecting the wrong operating frequency ?

Rgds,
Mahantesh

Wayneh is right - there's usually a lot of compromises in SMPSU design. pushing up the frequency lets you get away with smaller cheaper reactive components. But you soon start hitting bottlenecks - BJT B/E storage time, MOSFET gate capacitance charge/discharge power, Trr in rectifiers and eddy losses in core ferrites to name a few.

Run of the mill commercial units are often around 20 - 50kHz. Searching on various controller chips will turn up application notes for designs that run somewhere around 2MHz or so.

 

I can’t give you a complete answer but I can tell you that it’s a compromise. This is what engineering is about, finding a design that balances competing factors.

A higher frequency allows using smaller components for storing energy, inductors in this case. But the design challenge becomes increasingly more difficult with frequency. 10kHz might be easy while 10MHz is very difficult.

The design process is iterative. Pick a set of specifications you want to meet, select a topology, start simulating and choosing components, find out how high you can go with real components.

While you’re doing all this, keep in mind that it’s all been done already by experts and can be purchased for next to nothing on EBay.

Thank you Ian

 

I can’t give you a complete answer but I can tell you that it’s a compromise. This is what engineering is about, finding a design that balances competing factors.

A higher frequency allows using smaller components for storing energy, inductors in this case. But the design challenge becomes increasingly more difficult with frequency. 10kHz might be easy while 10MHz is very difficult.

The design process is iterative. Pick a set of specifications you want to meet, select a topology, start simulating and choosing components, find out how high you can go with real components.

While you’re doing all this, keep in mind that it’s all been done already by experts and can be purchased for next to nothing on EBay.

Thank you Wayneh...