👉 35V-5A Adjustable Switching Power Supply (DC to DC Buck Converter)

A DC-to-DC converter is one of the most commonly used circuits in electronics, especially in power supply applications. There are three major types of DC-to-DC converters (non-isolated): Buck, Boost, and Buck-Boost. Sometimes a buck converter is also called a step-down converter and a boost converter is also called a step-up converter.

In this article/video, I introduce an adjustable 5A DC-to-DC converter circuit that uses an advanced chip, made by Texas Instruments, which is TPS5450. It’s a high-frequency and efficient buck converter chip that provides tight voltage regulation. I have followed several PCB design rules to ensure low noise, low EMI, and high stability of the output voltage.

To design the schematic and PCB, I used Altium Designer 23 and shared the project with my friends using Altium-365. The fast component search engine (Octopart) allowed me to quickly consider components’ information and also generate the BOM. To get high-quality fabricated boards, I sent the Gerber files to PCBWay and tested the circuit for output stability and noise, using a DC load, a multimeter, and an oscilloscope. Soon later, I will also perform the step-response test and demonstrate the results.

Specifications
Input Voltage: 5.5V to 36V
Output Voltage: 1.22Vmin to 31Vmax (variable)
Output Current (continuous): 5A
Output Current (peak, short time): 6A
Maximum Output Drop: 22mV (5A load)
Output Noise: 14mVp-p (no load), 50mVp-p (5A load), 20MHz-BW

References

Full Article, Downloading PCB, Direct Order: https://www.pcbway.com/project/shareproject/5A_35V_Adjustable_Switching_Power_Supply_760ba488.html

[1]: TPS5450: https://octopart.com/tps5450ddar-texas+instruments-7105511?r=sp

[2]: SS56: https://octopart.com/ss56bf-hf-comchip-107339894?r=sp

[3]: 3590-S2: https://octopart.com/3590s-2-502l-bourns-112621?r=sp

6 hours ago, sam.moshiri said:

A DC-to-DC converter is one of the most commonly used circuits in electronics, especially in power supply applications. There are three major types of DC-to-DC converters (non-isolated): Buck, Boost, and Buck-Boost. Sometimes a buck converter is also called a step-down converter and a boost converter is also called a step-up converter.

In this article/video, I introduce an adjustable 5A DC-to-DC converter circuit that uses an advanced chip, made by Texas Instruments, which is TPS5450. It’s a high-frequency and efficient buck converter chip that provides tight voltage regulation. I have followed several PCB design rules to ensure low noise, low EMI, and high stability of the output voltage.

To design the schematic and PCB, I used Altium Designer 23 and shared the project with my friends using Altium-365. The fast component search engine (Octopart) allowed me to quickly consider components’ information and also generate the BOM link. To get high-quality fabricated boards, I sent the Gerber files to PCBWay and tested the circuit for output stability and noise, using a DC load, a multimeter, and an oscilloscope. Soon later, I will also perform the step-response test and demonstrate the results.

Specifications
Input Voltage: 5.5V to 36V
Output Voltage: 1.22Vmin to 31Vmax (variable)
Output Current (continuous): 5A
Output Current (peak, short time): 6A
Maximum Output Drop: 22mV (5A load)
Output Noise: 14mVp-p (no load), 50mVp-p (5A load), 20MHz-BW

 

References

Full Article, Downloading PCB, Direct Order: https://www.pcbway.com/project/shareproject/5A_35V_Adjustable_Switching_Power_Supply_760ba488.html

[1]: TPS5450: https://octopart.com/tps5450ddar-texas+instruments-7105511?r=sp

[2]: SS56: https://octopart.com/ss56bf-hf-comchip-107339894?r=sp

[3]: 3590-S2: https://octopart.com/3590s-2-502l-bourns-112621?r=sp

 

If you get a "for parts or not working" power supply from certain reputable manufacturers you should be able to fix it. Make sure you can find the service manual and check it that the device does not have proprietary parts. Certain power supplies are so common repair parts are also common. I found a triple Sorensen XT power supply that already was 2/3 working units so I just fixed the part that wasnt and now I have a really solid triple supply. Apart from a hum (a physical hum, the DC output is incredibly quiet, as quiet as a battery) its perfect. But it weighs maybe 30 or 40 lbs. Its a real boat anchor. If it was bought 100% working it would have cost me at least $250 even used and >35 yrs old.

Thanks for sharing the design and the video. I came across this design and found it good too: 

https://www.pcbway.com/project/shareproject/power_supply_0_30V_2mA_3A_version2_28ca8ff0.html

But your power supply has a bigger voltage and current rating I can see.

On 3/2/2023 at 8:16 AM, bidrohini said:

Thanks for sharing the design and the video. I came across this design and found it good too: 

https://www.pcbway.com/project/shareproject/power_supply_0_30V_2mA_3A_version2_28ca8ff0.html

 

But your power supply has a bigger voltage and current rating I can see.

 

That is a linear supply, but what I posted here is switching and very small, you can embed it in whatever enclosure and control the voltage using the potentiometer