All Questions
Tagged with buck switch-mode-power-supply
311
questions
9
votes
1
answer
3k
views
Switching regulator output is unstable
I have a problem in buck regulator. I'm using L4970A to make a buck regulator with a variable output that can be adjusted using a potentiometer.
Output is becoming a ramp when I set the output ...
- 103
1
vote
2
answers
2k
views
What are the important considerations when choosing a pass transistor and bias resistor for a buck regulator?
The MC34063 datasheet shows this diagram for a buck configuration with an external (NPN) transistor (in order to be able to handle higher loads than 750mA):
Neither the datasheet nor the application ...
- 7,749
30
votes
4
answers
22k
views
Why do smaller loads require larger inductors in buck regulators?
The MC34063 Application Note lists the equation for calculating minimum inductor size as follows:
$$L_{min} = \frac{V_{in} - V_{sat} - V_{out}}{I_{pk}(switch)} t_{on}$$
But this implies that as Ipk(...
- 7,749
19
votes
6
answers
14k
views
Why do buck (step-down) switching regulators require an inductor and diode?
So, I understand, at least at a basic level, the method of operation of switching converters, both buck and boost. What puzzles me, though, is why buck converters in particular aren't simpler.
Why ...
- 7,749
2
votes
3
answers
4k
views
How to adjust the voltage of this SMPS?
I bought this kind of module for my led light project. Unfortunately it did not come with instructions.
It can be found from eBay with "3.5-28V to 1.25-26V DC-DC Converter Boost Buck Step Up Step ...
- 1,047
6
votes
5
answers
2k
views
Determine efficiency of converter
I would like to determine as accurately as possible (ideally within an error limit of +/- 0.25% or better, but I guess that's nigh impossible) the efficiency of a converter, using a simple method.
I ...
- 993
9
votes
3
answers
5k
views
SMPS PCB Design Critic
Oldest versions of this post can be viewed through this link.
This is my re-designed layout. What is your view again?
10-32V to 5V 1.2A SMPS Buck Regulator Design.
The IC is IFX91041 from infineon.
...
- 5,970
3
votes
3
answers
3k
views
Buck converter with feedback loop
According to this site in a buck converter with voltage mode control the duty cycle is set directly by comparing a voltage ramp to an error voltage. I agree with that. But this is where my headache ...
- 133
2
votes
1
answer
528
views
Critique my SMPS buck design, take 2
After getting some helpful critiques from my original post;
Critique my SMPS buck design
I worked on my design and made a few major changes.
L1: 3.3uH 2A inductor
C1: 10uF 25V ceramic cap
C2: 0....
- 31.9k
18
votes
1
answer
17k
views
How important is self-resonant frequency for an inductor when used in a fast (~3MHz) buck SMPS?
I'm using the LM2734Z, a 3 MHz buck regulator. It's really fast which means it has a small inductor.
One of the things I'm wondering is how important is the self-resonant frequency of the inductor? I'...
- 31.9k
8
votes
3
answers
1k
views
Critique my SMPS buck design
I'm using an LM2734 buck regulator to get +3.3V at 400mA. The datasheet is unclear on how to lay out the supply, so I tried to follow some common sense, keeping all power traces short where possible. ...
- 31.9k