Adjustable Power Supply - Electronic Circuits Projects Diagrams Free

icymint · 22nd January 2006, 05:50 AM

Hi, I'm new here. I'm currently working on a power supply project. Basically the output voltage of the power supply will be adjustable but I wanted to make 'digital'. That means there are two buttons for you to press to set a higher or lower voltage. I just want to know if it can be done and how. Thanks a lot!!!

Someone Electro · 22nd January 2006, 07:35 AM

An digital resistor will do exsactly what you want.Some use I2C,SPI... but some have two inputs for the up and down button so it makes it very simple.

You can also use an digital LCD dispay(not cheap).To make it look more digital.

It will also be internaly more digital if you use an switcmode regulator insted that makes much less heat,is more eficent and outputs more power.And it can also output more amps then the input at an lower voltage.

audioguru · 22nd January 2006, 07:36 AM

Use an LM317 1A, LM350 3A or LM338 5A adjustable voltage regulator IC from National Semi with a "digital pot" IC from Maxim. They have some digital pots that "remember" the last setting when power is turned off.
Their memory wears-out after a while, after which they power-up to the same setting each time.

icymint · 22nd January 2006, 06:25 PM

Guys, thank you very much for the feedback!!! I think the 'digital pot IC' is what i'm realli looking for. I'd tried looking for digital resistors in the past and it's too expensive for me but the ICs are cheap!!! Another question, if i include a PIC inside the power supply to control the voltage and display, will it be like overkill?

Thanks a lot!!!

audioguru · 22nd January 2006, 07:08 PM

I have a pot on mine that I calibrated with my accurate digital multi-meter. I don't even need a voltmeter on it but some kind of indication of it current-limiting would be nice to have.

Someone Electro · 22nd January 2006, 08:54 PM

An PIC would work fine to control an PSU.

This IC is a digital resistor.Its aculy taping in an resistor netowk at difrent points.This is all in the IC.

icymint · 23rd January 2006, 06:21 PM

Thank you very much for the feedbacks. I'd done some googling on switch mode regulators but I couldnt find any negative switchmode voltage regulator. Is it possible to make adjustable power supply with positive and negative output? Something like +5/0/-5, +23/0/-23...

Someone Electro · 23rd January 2006, 06:36 PM

Well whith switchmode you can regulate an huge curent like 20A whith no heat problems.

I dont know any such negative ones.But i seen ones that invert voltage quite a lot of times.Thease can make -12V from +12V

eblc1388 · 24th January 2006, 08:07 AM

Quote:

Originally Posted by icymint

Thank you very much for the feedbacks. I'd done some googling on switch mode regulators but I couldnt find any negative switchmode voltage regulator. Is it possible to make adjustable power supply with positive and negative output? Something like +5/0/-5, +23/0/-23...

Checks link below for an example on how it is done using a PIC.

Switchmode Power supply 0 to 20 volts at up to 4 amps in 0.1 volt increments

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22nd January 2006, 05:50 AM	#1
icymint	Adjustable Power Supply Hi, I'm new here. I'm currently working on a power supply project. Basically the output voltage of the power supply will be adjustable but I wanted to make 'digital'. That means there are two buttons for you to press to set a higher or lower voltage. I just want to know if it can be done and how. Thanks a lot!!!

22nd January 2006, 07:35 AM	#2
Someone Electro	An digital resistor will do exsactly what you want.Some use I2C,SPI... but some have two inputs for the up and down button so it makes it very simple. You can also use an digital LCD dispay(not cheap).To make it look more digital. It will also be internaly more digital if you use an switcmode regulator insted that makes much less heat,is more eficent and outputs more power.And it can also output more amps then the input at an lower voltage. __________________ Il give you shocking experience.

22nd January 2006, 07:36 AM	#3
audioguru	Use an LM317 1A, LM350 3A or LM338 5A adjustable voltage regulator IC from National Semi with a "digital pot" IC from Maxim. They have some digital pots that "remember" the last setting when power is turned off. Their memory wears-out after a while, after which they power-up to the same setting each time. __________________ Uncle $crooge

22nd January 2006, 06:25 PM	#4
icymint	Guys, thank you very much for the feedback!!! I think the 'digital pot IC' is what i'm realli looking for. I'd tried looking for digital resistors in the past and it's too expensive for me but the ICs are cheap!!! Another question, if i include a PIC inside the power supply to control the voltage and display, will it be like overkill? Thanks a lot!!!

22nd January 2006, 07:08 PM	#5
audioguru	I have a pot on mine that I calibrated with my accurate digital multi-meter. I don't even need a voltmeter on it but some kind of indication of it current-limiting would be nice to have. __________________ Uncle $crooge

22nd January 2006, 08:54 PM	#6
Someone Electro	An PIC would work fine to control an PSU. This IC is a digital resistor.Its aculy taping in an resistor netowk at difrent points.This is all in the IC. __________________ Il give you shocking experience.

23rd January 2006, 06:21 PM	#7
icymint	Thank you very much for the feedbacks. I'd done some googling on switch mode regulators but I couldnt find any negative switchmode voltage regulator. Is it possible to make adjustable power supply with positive and negative output? Something like +5/0/-5, +23/0/-23...

23rd January 2006, 06:36 PM	#8
Someone Electro	Well whith switchmode you can regulate an huge curent like 20A whith no heat problems. I dont know any such negative ones.But i seen ones that invert voltage quite a lot of times.Thease can make -12V from +12V __________________ Il give you shocking experience.