David_
Advanced Member level 2
Hello.
I'm building a dual rail power supply with LT3081(positive reg) and LT3090(negative reg) and i will not set the output voltage by use of a resistor but through feeding a external voltage into the set pin(not my idea and a lot of the basics for my supply is credited to David behind EEVBLOGG).
As David does i will simply feed a positive voltage into the positive regulators set pin and that will produce the same voltage at the regulator output, but it's something i don't get about the negative regulator.
In the data sheet at page 31 theres a picture that shows both types of regulators and its the background for my question.
http://cds.linear.com/docs/en/datasheet/3090fa.pdf
I don't even know what a 4-quadrant supply is but the lt3085 is just like the lt3081 but have I understood right when I think i need to supply the negative regulator with a negative voltage?(in my circuit)
But what seems odd to me is that comparing the two regs the positives set pin drives the +in of the amplifier and the negatives set pin drives the -in of its amplifier, and when I see them both connected to one and the same voltage I get somewhat confused. But as said i don't know what the circuits should do but it looks very strange to me.
In my circuit both regulators should output the same voltage with opposite polarity so by some means I need a positiv controll voltage for the positive reg and a negative controll voltage for the negative reg, true?
I realise that I need to aquire a better grasp of amplifiers but what would happen if I feed the negative regulators(lt3090) set pin with a positive voltage?
I'm building a dual rail power supply with LT3081(positive reg) and LT3090(negative reg) and i will not set the output voltage by use of a resistor but through feeding a external voltage into the set pin(not my idea and a lot of the basics for my supply is credited to David behind EEVBLOGG).
As David does i will simply feed a positive voltage into the positive regulators set pin and that will produce the same voltage at the regulator output, but it's something i don't get about the negative regulator.
In the data sheet at page 31 theres a picture that shows both types of regulators and its the background for my question.
http://cds.linear.com/docs/en/datasheet/3090fa.pdf
I don't even know what a 4-quadrant supply is but the lt3085 is just like the lt3081 but have I understood right when I think i need to supply the negative regulator with a negative voltage?(in my circuit)
But what seems odd to me is that comparing the two regs the positives set pin drives the +in of the amplifier and the negatives set pin drives the -in of its amplifier, and when I see them both connected to one and the same voltage I get somewhat confused. But as said i don't know what the circuits should do but it looks very strange to me.
In my circuit both regulators should output the same voltage with opposite polarity so by some means I need a positiv controll voltage for the positive reg and a negative controll voltage for the negative reg, true?
I realise that I need to aquire a better grasp of amplifiers but what would happen if I feed the negative regulators(lt3090) set pin with a positive voltage?
