Need some help building a buck converter with TL494 + BJT , Mosfet's .
Goal is variable buck converter , 0 ( or close as it can get ) to 35V at 2-3Amps.
I used lm2596 and I wasn;t happy with it. I want to build a " discrete" buck converter.
- I'm not sure how to use the two comparators for voltage adjustment ( done right ) so it changes duty cycle to maintain output voltage, let's say 5v and when I connect a 2amp load it will stay at 5v ( 4.9v at least ) not a few volts drop like I had with LM317 with output transistors for current boost.
I'm a noob when it comes to power supplies.
Here are a few example schematics I found.
https://www.diyaudio.com/community/threads/tl494-help.407455/
- Bruno.
Goal is variable buck converter , 0 ( or close as it can get ) to 35V at 2-3Amps.
I used lm2596 and I wasn;t happy with it. I want to build a " discrete" buck converter.
- I'm not sure how to use the two comparators for voltage adjustment ( done right ) so it changes duty cycle to maintain output voltage, let's say 5v and when I connect a 2amp load it will stay at 5v ( 4.9v at least ) not a few volts drop like I had with LM317 with output transistors for current boost.
I'm a noob when it comes to power supplies.
Here are a few example schematics I found.
https://www.diyaudio.com/community/threads/tl494-help.407455/
- Bruno.
Also it confuses me why I most of them use P channel mosfets , a N channel could be useed as well if you change it's " position:" in circuit .
I don;t want to make it " full smps" work on 220v.
DC TO DC buck, 35v input from a transformer.
Goal is " lab power supply, variable. smps ( buck converter I think would be best option ) not linear like LM723, LM317. )
I don;t want to make it " full smps" work on 220v.
DC TO DC buck, 35v input from a transformer.
Goal is " lab power supply, variable. smps ( buck converter I think would be best option ) not linear like LM723, LM317. )
It's perhaps worthwhile to appreciate how far you got with the LM2596, and why it may not have achieved what you want. Sometimes newbs make poor initial assumptions or design and prototyping and measurement choices, which unless corrected can continue on to the next project and cause similar unhappiness.
I do not believe the maximum range (reaching zero, or reaching the max volts) is achievable with PWM.
The LM358N appears to help with tight load regulation, if I'm not mistaken... I also believe that it can help reduce ripple and noise, induced along the wiring between the PCB DC out terminal, and load - at the load end... like ripple detection and correction, based on diff input CMRR ability.
The LM358N appears to help with tight load regulation, if I'm not mistaken... I also believe that it can help reduce ripple and noise, induced along the wiring between the PCB DC out terminal, and load - at the load end... like ripple detection and correction, based on diff input CMRR ability.
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