LT3791 datasheet(3/8 Pages) LINER

3 / 8 page

dc1666af

DEMO MANUAL DC1666A

DemonstrationcircuitDC1666Aiseasytosetuptoevaluate

theperformanceoftheLT3791.Followtheprocedurebelow:

NOTE: PWM must be pulled high to run. If PWM is not

used, connect PWM to a 5V source or to INTVCC on the

PCB using 0Ω resistor R22.

1. Connect a string of LEDs that will run with forward volt-

age less than 25.5V, but greater than 9.5V, to the LED+

and LED– terminals on the PCB as shown in Figure 1.

2. Connect the EN/UVLO terminal to GND.

3. With power off, connect the input power supply to the

PVIN and GND terminals. Make sure that the PVIN DC

input voltage will not exceed 60V.

4. ConnectthePWMterminal.IfPWMisnotused,connect

PWM to a 5V source or to INTVCC on the PCB using 0Ω

resistor R22. PWM must be pulled high to run.

5. Turn the input power supply on and make sure the

voltage is between 4.7V and 60V.

6. Release the EN/UVLO to GND connection.

7. Observe the LED string running at the programmed

LED current.

8. For PWM dimming, connect a PWM (100Hz or higher is

recommended) signal to the PWM terminal. For analog

dimming, connect a DC voltage between 0V and 2V to

the CTRL terminal.

9. Observe the reduction of brightness in the LED string

when PWM or analog dimming.

Quick start proceDure

LT3791 Datasheet(PDF) 3 Page - Linear Technology