Change Pot in Mini Buck Converter

[ThomsCircuit]

Heh....yeah....the 70's....

One of my fav shows. "Marsha, Marsha, Marsha"
Ive got some white smd leds (FV=2.8-3.2). Want to add them to the input and output. how would i do this when the voltage can vary from 4.5-24v input and 3-21v output?

 

[eTech]

One of my fav shows. "Marsha, Marsha, Marsha"

heh...

Ive got some white smd leds (FV=2.8-3.2). Want to add them to the input and output. how would i do this when the voltage can vary from 4.5-24v input and 3-21v output?

I thought you were using a digital display? why would you need an indicator?

 

[ThomsCircuit]

I thought you were using a digital display? why would you need an indicator?

i am. i just saw in on a converter and wondered how it was done. I did try looking it up but could not find any definitive information. I also purchased a few dozen about a month ago and thought this would be a good project to use them in.

 

[eTech]

i am. i just saw in on a converter and wondered how it was done. I did try looking it up but could not find any definitive information. I also purchased a few dozen about a month ago and thought this would be a good project to use them in.

Doesn't make sense, but anyway...

Use a simple constant current source, like a current mirror. The load would be the LED.

 

[ThomsCircuit]

Doesn't make sense, but anyway...

Use a simple constant current source, like a current mirror. The load would be the LED.

I see it here on this module. The input and output voltage is variable. I recognize all of the components. My design has most of these except for the two diodes. It just appears that the LED has just a resistor and nothing else restricting the current.

 

[eTech]

Use something like this current limiter.
The LED current is a constant 10mA and varies slightly over the whole voltage range.

 

[ThomsCircuit]

Use something like this current limiter.

Thank you. I have all those components in SMD! Except R2. Is that 62r?

 

[eTech]

Thank you. I have all those components in SMD! Except R2. Is that 62r?

Test it first...