Low Noise Adjustable Power Supply (30V-4A, CC-CV)

[Hesambook]

Power supplies are one of the most popular topics in electronics. There are two major types of regulated power supply: linear and switching. Both power supply types introduce some advantages and disadvantages, however, a linear power supply offers better line and load regulation figures and it handles lower noise at the output, specifically when the power supply is adjustable and the output is under load; although its efficiency is lower than a switching power supply. In this article/video, I introduced an adjustable 30V-4A linear power supply that provides constant voltage and constant current adjustment. The output noise of the power supply is low and has measured using the power analysis feature of the Siglent SDS2102X Plus oscilloscope. All component packages are through-hole, so you don't need any special tool for soldering. Let's get started!

Specifications
Input Voltage (max): 35V [30V, max-tested]
Output Voltage (min): 1.28V
Output Voltage (max-tested): 27.35V [28.9Vin, no load, 25C]
Output Current: 1.1mA to 4A(max continous)
Output Noise (no load): 6-7mVpp
Output Noise (1A load): 6-7mVpp
Output Noise (2A load): 8-10mVpp

YouTube:

References

Article: https://bit.ly/2XiQj3R

LM358 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/LM358N/NOPB/Texas Instruments

78L09 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/MC78L09ACPG/ON Semiconductor

LM338 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/LM338T/NOPB/Texas Instruments

IRLZ44 schematic symbol, PCB footprint, 3D model: https://componentsearchengine.com/part-view/IRLZ44NPBF/Infineon

Electronic designing CAD software plugins: https://www.samacsys.com/library-loader-help

Altium Designer plugin: https://www.samacsys.com/altium-designer-library-instructions

Siglent SDS2102x Plus oscilloscope: https://www.siglenteu.com/digital-oscilloscopes/sds2000xp

 

[00kam]

hello
i have seen your job (the video) it is a good job. although i have neglected interested with liner regulator
since a period because it becomes not practical in high current loads it is suitable for low current loads and we can say
for no concern about power loose and ignore the ripple increase voltage with high draw current.so
all this defect in new power supply design becomes an desired .
in your design i have seen the schematic diagram . the user connects the load to the terminals output which forms the" R load" of the "Mosfet IRZL44 " and the cuurent follows from the output regulator LM338(pin-2) passes through " user load --->D-S IRZL44 junction ---> 3.3omh 10W ---> GND) the amount current sense is done by taking a sample from" S -pin of IRZL44 via R1 10komh to inv pin(-) of LM358 O.P which it compares with reference voltage noninv pin(+) ) this is the idea to control the current while controlling the voltage is done by LM338 . i have question what if we connect +9 volt to (D-pin IRZL44 ) and disconnect RGND and do measure voltage over the 3.3omh with adjusting the current potentiometer what will see ?


kamal

 

[Hesambook]

hello
i have seen your job (the video) it is a good job. although i have neglected interested with liner regulator
since a period because it becomes not practical in high current loads it is suitable for low current loads and we can say
for no concern about power loose and ignore the ripple increase voltage with high draw current.so
all this defect in new power supply design becomes an desired .
in your design i have seen the schematic diagram . the user connects the load to the terminals output which forms the" R load" of the "Mosfet IRZL44 " and the cuurent follows from the output regulator LM338(pin-2) passes through " user load --->D-S IRZL44 junction ---> 3.3omh 10W ---> GND) the amount current sense is done by taking a sample from" S -pin of IRZL44 via R1 10komh to inv pin(-) of LM358 O.P which it compares with reference voltage noninv pin(+) ) this is the idea to control the current while controlling the voltage is done by LM338 . i have question what if we connect +9 volt to (D-pin IRZL44 ) and disconnect RGND and do measure voltage over the 3.3omh with adjusting the current potentiometer what will see ?


kamal

Laboratory power supplies must be linear because no switching supply can deliver such current with the minimum noise, especially if the supply is variable output noise gets worse in some current/voltages.

regarding your suggestion, 9V to the Drain, but where the regulator output should be connected (LM338 output)?

 

[00kam]

Laboratory power supplies must be linear because no switching supply can deliver such current with the minimum noise, especially if the supply is variable output noise gets worse in some current/voltages.

regarding your suggestion, 9V to the Drain, but where the regulator output should be connected (LM338 output)?

Hello
i agree with you liner power supply it is suitable for Laboratory use but under those conditions(cases )
(low draw current for electronic circuits design , double output in one unit liner power supply for driving high current application such as using high power lamps, solenoid valve , motors (but high ripple voltage) and the need for isolation from the mains power source ) but in the many of modern industrial equipment there is no use for a liner power supply because the high power loss maybe 50% of consumed power and high ripple output voltage when load draws high current (4 Amp is not low current)

regarding in my question it wasn't suggestion and neither re-design your liner supply it is just question
neglect the use LM338 only use the +9 volt that comes from " IC2 LM7809 " i was wanting to know that
IC1 LM358 is just another liner regulator

kamal

 

[Hesambook]

Hello
i agree with you liner power supply it is suitable for Laboratory use but under those conditions(cases )
(low draw current for electronic circuits design , double output in one unit liner power supply for driving high current application such as using high power lamps, solenoid valve , motors (but high ripple voltage) and the need for isolation from the mains power source ) but in the many of modern industrial equipment there is no use for a liner power supply because the high power loss maybe 50% of consumed power and high ripple output voltage when load draws high current (4 Amp is not low current)

regarding in my question it wasn't suggestion and neither re-design your liner supply it is just question
neglect the use LM338 only use the +9 volt that comes from " IC2 LM7809 " i was wanting to know that
IC1 LM358 is just another liner regulator

kamal

nothing happens. that would be a constant current load for the 9V rail and it will put the regulator under stress

 

[Hesambook]

Note: This is the first prototype, as I mentioned in the video, in the last revision of the PCB board (which is available for you), the distance between electrolytic capacitors and the power resistors has been increased, however, if you still have concerns about this, you can use 470uF-50V capacitors instead of 1000uf-50V capacitors which are smaller in diameter.