Constant Current Source, with Dimming Abilty

i came across this circuit while looking for a constant current source with the ability to dim the leds connected to it.

**broken link removed**

This one looks like it suits my needs perfectly. 48v @ 400ma output at 100% duty
plus it has the ability to dim the leds.

Problem is it requires a -48v supply, is there any way to do the same thing with a +48v supply.

need to keep the circuit with good efficiency, I am told that for the leds im going to use string of 24 x (2v @ 400ma), a simple current limiting resistor is no good.

is there any way to do the same thing with a +48v supply.

Click to expand...

Yes, just look at the datasheet for the device:

https://www.electro-tech-online.com/custompdfs/2010/10/MAX16822-MAX16822B.pdf

The -48v is just an adaption of the basic circuit.

JimB

I am using a ZXLD1366 in a similar project. It will drive up to 60v 1A and can do PWM dimming by adding an NPN transistor to the ADJ pin (described in the datasheet). You should check it out, it may be easier to use/cheaper than the MAX chip you link.