DC1039A-A Analog Devices

DEMO CIRCUIT1039 QUICK START GUIDE LTC3207/LTC3207-1 LTC3207/LTC3207-1 600mA Universal Multi- Output LED/CAM Driver DESCRIPTION 2 and intensity are achieved via an I C serial interface. See WARNING the LTC3207/LTC3207-1 data sheet for more information on this process. There are 64 dimming states available Do not look directly at operating LED. for the universal LEDs and 16 dimming states for the This circuit produces light that can damage eyes. camera LED. The charge pump optimizes efficiency based on the volt- Demonstration circuit 1039 is a 600mA Universal Multi- age across the LED current sources. The part powers up Output LED/CAM Driver with six white LEDs, two RGB in 1x mode and will automatically switch to boost mode LEDs, and a camera flash featuring the whenever any enabled LED current source begins to drop LTC3207/LTC3207-1. out. The first dropout switches the part to 1.5x mode and The LTC3207/LTC3207-1 is a low noise charge pump a subsequent dropout switches the part into 2x mode. designed to drive 12 universal LED (ULED) current The part resets to 1x mode whenever a data byte is up- 2 sources and one high current camera flash. The dated via the I C port. LTC3207/LTC3207-1 requires only five small ceramic Design files for this circuit board are available. Call capacitors to form a complete LED power supply and the LTC factory. current controller. L, LTC, LTM, LT are registered trademarks of Linear Technology Corporation. Other product The maximum display currents are set with an internal names may be trademarks of the companies that manufacture the products. precision current reference. On/Off blinking, gradation, QUICK START PROCEDURE Demonstration circuit 1039 is easy to set up to evaluate 3. Connect DC1039 to the DC590 USB Serial Controller the performance of the LTC3207/LTC3207-1. Refer to using the supplied 14-conductor ribbon cable as Figure 1 for proper measurement equipment setup and shown in Figure 1. follow the procedure below: 4. With power off, connect the input power supply to NOTE. When measuring the input or output voltage ripple, care VBAT and GND with a series ammeter and a voltmeter must be taken to avoid a long ground lead on the oscilloscope as shown in Figure 1. probe. Measure the input or output voltage ripple by touching the probe tip directly across the VBAT and GND terminals. See Turn on and set the input power supply between 2.9 5. Figure 2 for proper scope probe technique. 5.5V. The DC1039 has an extra 4.7uF de-coupling ca- TM 1. Refer to the DC590 Quick Start Guide for QuikEval pacitor between VBAT and GND to help accommodate setup and software installation details. long VBAT source lead lengths. The DC590 board gets its power from the USB cable. 2. Make sure the USB cable is connected between the NOTE. Make sure that the input voltage does not exceed 6V. computer and the DC590 controller board. NOTE. If using the DC590B board, a specific DVCC voltage level 6. Run the QuikEval program. The program detects the may be selected. This is done by setting the VCCIO jumper on the DC1039 and displays the LTC3207 control window DC590 board to one of the following settings: 3.3V, 5V, removed (shown in Figure 3). for 2.7V or set to external if use of an external supply is desired. 1GND VIN LTC3207/LTC3207-1 Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2