QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 629 MULTI-DISPLAY LED CONTROLLER LTC3205 DESCRIPTION Demonstration circuit 629 is a multi-display LED con- Dimming and ON/OFF control for all displays is achieved troller featuring the LTC3205. via a 3-wire serial interface. Four dimming states exist for the main and sub panel displays and 16 dimming The LTC3205 is a highly integrated multi-display LED states are available via internal PWM for the red, green, controller. This device contains a high efficiency, low and blue LEDs resulting in up to 4096 color combina- noise fractional step-up/step-down charge pump to pro- tions. vide power for a main and sub white LED display, plus an RGB color LED display. The LTC3205 requires only The LTC3205 charge pump optimizes efficiency based four small ceramic capacitors plus two resistors to form on V and LED forward voltage conditions. The part IN a complete 3-panel LED power supply and a current powers up in step-down mode and automatically controller. switches to step-up mode once the first LED current source begins to enter dropout. Internal circuitry pre- Maximum currents for the main/sub and RGB displays vents inrush current and excess input noise during start- are set independently with a single resistor. Current for up and mode switching. each LED is controlled with an internal current source. QUICK START PROCEDURE Demonstration circuit 629 is easy to set up to evaluate 3. Run the QuickEval program. The program detects the performance of the LTC3205. Refer to Figure 1 for the DC629 and displays the LTC3205 control window proper measurement equipment setup and follow the (shown in Figure 2). procedure below: 4. Attach a 2.7V4.5V power source to the Vin and GND 1. Connect DC629 to the DC590 USB Serial Controller turrets of the DC629 demo board. This is the V IN using the supplied 14-conductor ribbon cable as power supply for the LTC3205 (see attached sche- shown in Figure 1. Refer to the DC590 Quick Start matic). guide for software installation details. NOTE: The LTC3205s maximum current settings for 2. Attach the supplied USB cable into your computer and Main, Sub, and RGB are set by R2 and R3 (see the at- then into the DC590 controller board. tached DC629 schematic.) R2 = R3 = 32.4k, which set the maximum current to 15mA. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 629 MULTI-DISPLAY LED CONTROLLER Figure 1. Proper Measurement Equipment Setup USING THE LTC3205 QUICKEVAL SOFTWARE The program provides brightness controls for the Main, the red, green, and blue LEDs to make any of the 4096 Sub, and RGB LEDs, an OFF/ON button which controls colors available. The hex code and color are displayed in output to the DC629 demo board, three demo buttons, small boxes to the right of each slider. They too are ad- and a CIE Chromaticity diagram which allows direct se- justed by clicking on the left and right arrows, a higher lection of colors. or lower tick, or by clicking and dragging the slide pointer. OFF/ON Click this button to begin outputting data to the LTC3205. The default state is OFF. The 16-bit hex CIE Chromaticity diagram Colors can be selected by code transmitted to the LTC3205 is shown in the HEX clicking on a specific color in the diagram. The Gamut OUT box when this button is on. box, when checked, displays the Chromaticity coordi- nates of the Nichia NSCM315C RGB diode forming a MAIN and SUB control These are vertical slide con- triangle or gamut of all the colors which can be pro- trols which adjust the main and sub LED output from 0 duced by that diode. to 100% by clicking on the up and down arrows, a higher or lower tick, or by clicking and dragging the BRIGHTNESS This is a horizontal slider used to ad- slide pointer. just the intensity of a color that has been chosen. It is also adjusted by clicking on the left and right arrows, a RED, GREEN, and BLUE controls These are horizon- tal slide controls which allow individual adjustment of 2