In my project i have to use CST-90 led which having electrical specification as (Vf=2.5v to 3.9v, I = upto 13.5 A).
I searched on google but not found reliable driver. so which kinda of driver i can use.
I want to dim it using PWM.

 

13.5 amps is a maximum value for a ten percent duty cycle. The average current for continuous operation is 3 amps. Look for a 3 amp driver. You may have better luck.

 

What current?
Just one or more in series/parallel?
PWM voltage?
Do you want to build a driver or a pre-packaged plug it in and go driver.

 

i also want this driver.
Current is 15Ampere
One led only that is CBT-140
PWM voltage is 5Volt.

 

i also want this driver.
Current is 15Ampere
One led only that is CBT-140
PWM voltage is 5Volt.

And what duty cycle to you intend to run this LED at?

 

Duty cycle may vary to change intensity.

 

Duty cycle may vary to change intensity.

Let me rephrase that then..
As you can see from the posts above the "maximum" current rating of these devices is ONLY for a 10% duty cycle or lower.. If you attempt to run it at 15 Amps continuously (or for more than a few seconds even) you will more than likely overheat/destroy it rapidly without some serious heatsinking..
So based on your intended use do you really think you need a 15 Amp constant current driver or would something much smaller suffice for your application.
Finding an off the shelf 15 Amp (and low voltage) constant current driver is going to be very tough to find..

Or are you interested in actually constructing a constant current power supply from discrete components/building a circuit board,etc...
Or how about a high wattage resistor?

Give us more details on your intended use please..