Abstract： With more than 500 mA output current capability， the NCP5608 is capable to drive the high power LED used in the portable photo flash system. Although the embedded I2C makes programming the chip very easy， it turns out that the flash can be trigged by the camera with no access to the I2C protocol. In this case， an extra function is necessary to support this specific pulse mode. This Application Note depicts a simple way to implement such a need without sacrificing extra GPIO at MCU level.

　　The current of each block can be set up independently by means of the I2C protocol， the maximum current being accurately preset by an external resistor. On the other hand， using such an external reference yields a very tight matching between the LED of a given block： typical 0.2% matching is achieved without the need for extra adjustment. The Charge Pump converter is capable to supply the total current continuously， assuming the PCB is designed to evacuate the heat coming from the operation. Generally speaking， the two blocks are used for their respective function， but one can connect all the LED pins to a single power full LED to generate a 500 mA flash pulse. It is possible also to combine the LED to get the most appropriate function in a given application： sharing the Flash and the Torch becomes very easy to implement.