Hi! I need to control a buck converter's output voltage by changing the duty cycle of a PWM signal. i am planning to use ARDUINO NANO ATMEGA328 EVAL BRD to implement 500 kHz PWM signal with a duty cycle change input digitally. Can you please suggest whether it will be a feasible idea or not? Any help or code hints will be highly appreciated...
It can be done, but the resolution of such pwm will be 5 bit only, so the duty range will be 0-31
2 Likes
This sounds like a suitable application for a simple timer IC.
But why do you want to use 500kHz? A lower frequency would be much more sensoible and the output of a PSU can not change much in 1 microsecond!
The higher the frequency the smaller the transformator will be. Some of these tiny DC-DC-step-down-converters work on 1 MHz.
But you should describe the final purpose that you want to have and you should give an overview about the project. It happends very often that - as soon as the final purpose is known and the thread-opener has given an overview about his project that experienced users can make suggestions for alternative and good solutions.
If all you want is a digital adjustable voltage that does only change from time to time.
Using a MOS-FET and a lowpass-filter would be much better suited.
Depending on how much current you need it might be sufficient to use a DAC-chip or a OpAmp configured as a voltage-follower with capacitors on input- and outputside.
But without knowing the final purpose and details like the voltage and current it can't be said if this would be a good solution.
1 Like
On DPin-9, you can have 500 kHz variable duty cycle using TC1:
Mode-14 Single Slope Fast PWM
Choose N (TC1 clock prescaler) at 1
Load ICR1 by 31 // f = 16 MHz/N(1+ICR1)
Use OCR1A to contol duty cycle
Hi StefanL38! Thanks for your response. The idea of my project is to build a buck converter that will have the input of 1000 V DC and then I can adjust the voltage from 300V to 900V DC only by changing the duty cycle (D= 0.3 to 0.9) of the corresponding MOSFET's gate driver signal. Will your solution be feasible for this application?
The buck converter circuit you build doesn't need a 500kHz PWM signal.
No at all. Usual DAC-Chips and OpAmps are for voltages as low as 5V to maybe 50V.
1000 V DC in words one thousand Volt DC voltage are a danger for life !
From your questions I assume that you have a rather limited knowledge about electriciy / electronics.
If you are not experienced how to deal with such high voltages you should not tinker with them at all.
DC voltages are more dangerous than AC voltages. Because with a DC-voltage your muscles wil cramp and as long as the DC-voltage is "ON" your brain will never ever be able control your muscels against a DC voltage higher than 120V. With wet hands even 50V will be dangerous.
And you want to tinker around with 1000V DC on the inputside and 300 V to 900V on the outputside ?? !!!!
Go searching for a different hobby. Still thrilling but much less dangerous than 300 V to 1000V DC.
Can you swim good? How about slackline-walking over a cold-water pool?
Seriously: stop tinkering with such high voltages !
1 Like
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.