Designing a buck converter

[RenoX023]

I’m working on a project where I need to step down 24V to a stable 5V with a load current of up to 1A. I’ve decided to use a buck converter based on the LM2675 IC.
My schematic was made in DipTrace.

Input: 24V (DC)
Output: 5V / 1A
Controller: LM2675
Switching Frequency: 260 kHz
I’m planning to use two capacitors:
Input Capacitor (C1): To smooth the input voltage and suppress noise.
Output Capacitor (C2): To smooth the output voltage and minimize ripple.
I have the following questions and concerns:
Type and value of the input capacitor: I’m considering using a 100 µF electrolytic capacitor with low ESR, but I’ve heard that ceramic or polymer capacitors might be better for high-frequency applications. Which type would be optimal for input noise suppression?
Type and value of the output capacitor: Given the need to minimize output ripple, should I use multiple low ESR ceramic capacitors or a single large electrolytic capacitor? Or perhaps a combination of both?
Impact of switching frequency on capacitor selection: How does the 260 kHz switching frequency affect capacitor choice? Should this be a factor when determining capacitance?
Temperature stability: The system will operate at elevated temperatures (up to 70°C). Which type of capacitor is best suited for these conditions?
I’d appreciate any advice or suggestions! I’m especially interested in hearing from anyone who has experience with similar circuits.
By the way, how do you like DipTrace 5? Has anyone tried working on it yet?

 

[bidrohini]

Add a 1 µF to 10 µF ceramic capacitor in parallel with C1 for better input noise suppression. Consider adding one or two 10 µF ceramic capacitors in parallel with C2 to reduce output ripple. Since your circuit will operate up to 70°C, ensure that all capacitors, especially electrolytics, are rated for at least 105°C to avoid any reliability issues. By the way, here is a deeptrace related blog post that you may like: https://www.pcbway.com/blog/25/PCB_Design_Tutorial_with_DipTrace_for_beginners.html

[BreanneJJustice]

On 8/20/2024 at 1:43 PM, RenoX023 said:

I’m working on a project where I need to step down 24V to a stable 5V with a load current of up to 1A. I’ve decided to use a buck converter based on the LM2675 IC.
My schematic was made in DipTrace.

Input: 24V (DC)
Output: 5V / 1A
Controller: LM2675
Switching Frequency: 260 kHz
I’m planning to use two capacitors:
Input Capacitor (C1): To smooth the input voltage and suppress noise.
Output Capacitor (C2): To smooth the output voltage and minimize ripple.
I have the following questions and concerns:
Type and value of the input capacitor: I’m considering using a 100 µF electrolytic capacitor with low ESR, but I’ve heard that ceramic or polymer capacitors might be better for high-frequency applications. Which type would be optimal for input noise suppression?
Type and value of the output capacitor: Given the need to minimize output ripple, should I use multiple low ESR ceramic capacitors or a single large electrolytic capacitor? Or perhaps a combination of both?
Impact of switching frequency on capacitor selection: How does the 260 kHz switching frequency affect capacitor choice? Should this be a factor when determining capacitance?
Temperature stability: The system will operate at elevated temperatures (up to 70°C). Which type of capacitor is best suited for these conditions?
I’d appreciate any advice or suggestions! I’m especially interested in hearing from anyone who has experience with similar circuits.
By the way, how do you like DipTrace 5? Has anyone tried working on it yet?

 

 
For the input capacitor, I'd recommend adding a ceramic capacitor (1-10 µF) alongside the 100 µF electrolytic to handle high-frequency noise. For the output, a combination of low ESR ceramics and a 100 µF electrolytic should minimize ripple effectively. I was looking for some affordable help with my law essays and came across https://www.linkedin.com/pulse/top-5-law-essay-writing-services-cheap-help-studymoose-gs99e The article gives a clear list of cheap and high-quality options. If you're in law school and need extra help with your essays without breaking the bank, I recommend checking this out. It made the process easier for me!

Any update?