DC510A Analog Devices

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 510 1WATT CCFL POWER SUPPLY LTC1697 DESCRIPTION Demonstration Circuit 510 is a 1Watt single output Using the LTC1697 with the Royer topology results in CCFL inverter with internal PWM dimming and bot- a particularly low component count design. Target tom bulb sense feedback features. The Demo Board applications for this Demo Board are PDAs such as consists of a LTC1697 CCFL Controller and a Royer Handheld Computers, Handheld GPSs with Map Dis- converter that uses bipolar transistors. The LTC1697 plays, and Handheld TV Video Monitors. also features internal CCFL short circuit and over- DC510 is designed to operate off a single Li-Ion cell voltage protection. The maximum lamp current is set for a Vin range of 2.7V 5.5V and outputs 100s of by a single resistor while a 1V 2V Dimming input volts at milliAmp current levels. allows the user to set the desired lamp current any- Design files for this circuit board are available. Call where between 0 and the maximum CCFL current set the LTC factory. by R5. QUICK START PROCEDURE DC510 is easy to set up to evaluate the performance 2. Ground the LCD Casing through the DC510 GND of the LTC1697. Refer to Figure 1 for proper meas- terminal. urement equipment setup and follow the procedure 3. Apply 2.7V 5.5V across the VIN & GND termi- below: nals. 1. Connect the LCD CCFL across the E1 & E2 termi- 4. Apply 1.0V 2.0V across the VDIM & GND termi- nals. Connect the positive CCFL wire to E2 and the nals, measuring the CCFL current for the desired negative wire of the LCD to E1. output CCFL current. Warning: There may be 100s of volts across the E1 & E2 terminals, across the capacitor C1, and on the secondary side of the transformer T1 that can be harmful if the user accidentally or otherwise touches these points. Figure 1. Proper Measurement Equipment Setup 1QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 510 1WATT CCFL POWER SUPPLY 2