QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 805 LOW NOISE HIGH CURRENT LED CHARGE PUMP LTC3216 DESCRIPTION Demonstration circuit 805 is a low noise high current circuit enters low-power mode for battery-life preser- LED charge pump featuring the LTC 3216 and the vation. LXCL-PWF1 Lumileds Luxeon Flash. The board is op- A red/green LED indicates the state of the PIC. The timized for 800mA 300ms LED flash current or LED is ready to flash or torch if the state indicator is 200mA constant LED torch current with a single lith- blipping green. If the indicator is not on, the PIC is ium ion battery input voltage range of 2.9V to 4.4V or turned off. For a brief time after the flash has oc- three AAA batteries in series. The lithium ion battery curred, the state-indicator LED is red, indicating that input voltage range, high LED flash current and sepa- another flash cannot happen, even if the button is rate torch mode current setting, internal charge pump pressed, until the red LED is off and the green LED is switches, inductorless solution, minimal external blipping again. components, and simple design makes the LTC3216 The LTC3216 datasheet gives a complete description is the top solution for space-constrained cellular tele- of the part, operation and applications information. phone camera flash solutions. The datasheet must be read in conjunction with this DC805 comes with three AAA batteries in series to Quick Start Guide for demonstration circuit 805. In simulate the capabilities of a typical lithium ion cellu- addition, Lumileds Luxeon Flash datasheet featuring lar telephone battery. This portable board is turned on LXCL-PWF1 (www.lumileds.com) must be read to and off by pressing the ON/OFF button. A TORCH but- understand thermal and LED current constraints for ton turns the LED on at 200mA for cellular telephone varying flash current pulse-widths and intensity. The video recording. The FLASH button flashes the LED at LTC3216 is assembled in a small low profile DFN 800mA for 300ms for cellular telephone camera flash package. Proper board layout is essential for maxi- operation. The buttons control the state of the PIC mum thermal performance. See the datasheet section microcontroller IC that is programmed with DC805 Layout Considerations. software. The PIC keeps the LED from being flashed Design files for this circuit board are available. Call constantly, preventing overheating and burnout. The the LTC factory. PIC also controls the flash time. When no buttons are pressed for a short time, the PIC turns off and the LTC is a trademark of Linear Technology Corporation QUICK START PROCEDURE Demonstration circuit 805 is easy to set up to evalu- plugging a power supply through wire leads to the ate the performance of the LTC3216. Follow the pro- demonstration circuit can cause the voltage on the cedure below: extremely low-ESR ceramic input capacitor to ring to twice its DC value. See Application Note 88 for more NOTE: Make sure that the input voltage does not ex- details. ceed 5V if a source other than the three AAA batteries is used. NOTE: Connect the three AAA batteries as indicated in the battery pack with the polarity indicated on the NOTE: If batteries are not used, do not hot-plug the back of the PCB. input voltage terminals VIN (+) and GND (-). The ab- solute maximum voltage on VIN is 5V and hot- 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 805 LOW NOISE HIGH CURRENT LED CHARGE PUMP 1. Insert three AAA batteries in the battery pack on 5. Press TORCH to turn off the 200mA video mode. the back of the PCB. 6. Press ON/OFF to turn off the circuit or let the cir- 2. If the state-indicator LED is not blipping green, cuit turn off by not pressing any buttons for ap- press the ON/OFF button to turn on the circuit. proximately 10 seconds. 3. Press FLASH to observe a 300ms, 800mA camera flash on the LXCL-PWF2 LED. 4. Press TORCH to observe constant 200mA LED light for recording video. 2