Hi all.
After snooping around a little bit I need short hints to build a "easy" voltage source to output 0,6 to 3V selectable by a trimpot beginning from a 12V input, with a current of a couple of mA (5mA). Accuracy and temp stability should not be an issue. I have seen different Vref IC from Analog Devices but I was wondering if an old fashion couple of transistors or better MOS could be the circuit.
Where should I point the direction to?
Best regards and thanks.

 

Hi all.
After snooping around a little bit I need short hints to build a "easy" voltage source to output 0,6 to 3V selectable by a trimpot beginning from a 12V input, with a current of a couple of mA (5mA). Accuracy and temp stability should not be an issue. I have seen different Vref IC from Analog Devices but I was wondering if an old fashion couple of transistors or better MOS could be the circuit.
Where should I point the direction to?
Best regards and thanks.

Welcome to AAC.

What is the application for this circuit?

 

Hi. Thank You for Your quick reply. I have an IC (Infineon's IL6150) that is a LED driver. It accepts at PIN2 an external analog voltage from 0,6V to 3V to steer its internal PWM generation acording to this picture in the datasheet:

 

It seems that you would be able to use a cheap 3.3V voltage standard chip and a potentiometer wired as a voltage divider.

 

..... or perhaps an 'amplified diode' :-


Edit:
My reading of the datasheet for the ILD6150 is that the PWM pin sources current (~12uA). So I doubt your reference needs to supply 5mA.

 

thanks alot. i didn't realize how simply with the 3.3V!!!! btw I know that it needs less than 5mA but, as far as I had experienced by measuring in the lab by prototyping, connecting a variable psu and helding current to 1mA @2.5V i didn't manage to steer the pin correctly.
When an input pin Sources current do you think that also connecting a R=(4.3V/12uA) trimpot directly to the output would do the rest? best regards again.

 

Worth a try. See what voltage you get across a 100k resistor connected between pin PWM and ground.