Our LCD has 10 series white LEDs for backlight with total Vf of 15V and current of 40ma. The backlight circuit is designed with SC4509. As per the datasheet its recommended output voltage is 20V and output current of 30ma. This translates to 20V * 30ma = 600mW. Our design also 15V * 40ma = 600mW. So is it correct assumption that the IC can be used in this design since the total power remain with in the limit? or the output current has to be less than 30ma irrespective of the output voltage? The max switch current limit of SC4509 is 500ma.