Author Topic: Help designing simple buck converter  (Read 831 times)

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Offline KEIN NEINTopic starter

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Help designing simple buck converter
« on: June 10, 2019, 01:10:21 pm »
I am using this book as a reference:

https://www.amazon.com/Power-Supply-Cookbook-Design-Engineers/dp/075067329X/ref=sr_1_1?keywords=power+supply+cookbook&qid=1560171597&s=gateway&sr=8-1

I was planning to design a buck-converter for a CPU but to my understanding nowadays all motherboards and graphics cards use multiple syncronous-buck converters driven by a voltage controller so it's to complex and I don't think I'll be able to implement that anytime soon.

So I'd rather build a simple buck-converter employing a shottky-diode and a power MOSFET. But can you give me real-world scenarios in which these are used? I am particularly interested in computer applications.

Some of my ideas are:

12V to either 5V or 3.3V PC SMPS DC-DC power converter

9V to 5V step-down (for attaching a battery to a USB port and charging stuff)

pico-PSU (though I am not sure wether or not a pico-PSU is an actual buck converter)

Thanks in advance
 

Offline KEIN NEINTopic starter

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Re: Help designing simple buck converter
« Reply #1 on: June 10, 2019, 01:13:28 pm »
I need this data:

Input voltage range,
Output voltage,
Maximum output current,
Output ripple voltage,
Output regulation,
 

Offline erikka

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Re: Help designing simple buck converter
« Reply #2 on: June 10, 2019, 05:34:38 pm »
For inspiration for a simple buck converter look here https://www.onsemi.com/pub/Collateral/MC34063A-D.PDF
 

Offline HB9EVI

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Re: Help designing simple buck converter
« Reply #3 on: June 10, 2019, 05:45:04 pm »
there are many real world scenarios for any size of buck converters, for beginners to mention is the higher efficiency; 5V from 12V with a LM7805 and 1A current draw results in a loss 7W while only using 5W - an efficiency of only about 29% ; with an efficient buck converter you can reach 95%

not only you save energy, you save on heatsink size as well.

somethin what you cannot do with linear regulators at all is upconversion, so from lower to higher voltage, a boost converter, or from a positive voltage to a negative voltage - an inverter
 


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