Buck Converter

1331

1d 12:37:21

An old circuit I dug up, edited for slight improvements.

These are probably the simplest switchmode converters. All it's really doing is a PWM of the power supply and then cleaning up the output voltage with an LC filter (a slight oversimplification but close enough).

published 10 years ago

infamousjeff

10 years ago

cool!

Zafeirakis

10 years ago

The reason the output is strongly dependent to the load is because the converter is operating in discontinuous mode (in other words the inductor current reach zero)...If you manipulate the elements values so that the inductor current doesnt reach zero, then you operate in continuous conduction mode and the output DC voltage is D*Vin where D is the duty cycle...So the output voltage is only dependent to the duty cycle...

Mamish

10 years ago

Yeah I probably should have fixed that up ages ago. I tweaked the inductor to put it in continuous for 10ohm, but the problem remains when the resistance increases, and that's not fixable without massively increasing inductance since the duty is fixed. A controller could compensate by decreasing duty... might be a good followup project.

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