The RT9272 is a high efficiency step-up DC-DC converterspecifically designed for dual panel mobile phoneapplications.According to SP status, RT9272 can either regulates outputcurrent flowing through series-connected LEDs for mainpanel or for sub panel with a common output LC filter. Thisalong with compact VDFN-10L 3x3 package and highswitching frequency allows less part count and smallerexternal components for space and cost saving.Pulling low EN pin shuts down the chip and reduces thesupply current to less than 1uA. The EN pin also acceptsPWM signal for LED brightness dimming control. Theaveraged LED current is well proportional to the duty cycleof the PWM signal. The internal soft start reduces inrushcurrent during EN turning on or PWM dimming control.Other features include OVP, OCP and OTP. OVP preventsthe damages in case of feedback loop open.