RT9272 pdf datasheet (High Per

The RT9272 is a high efficiency step-up DC-DC converter
specifically designed for dual panel mobile phone
applications.
According to SP status, RT9272 can either regulates output
current flowing through series-connected LEDs for main
panel or for sub panel with a common output LC filter. This
along with compact VDFN-10L 3x3 package and high
switching frequency allows less part count and smaller
external components for space and cost saving.
Pulling low EN pin shuts down the chip and reduces the
supply current to less than 1uA. The EN pin also accepts
PWM signal for LED brightness dimming control. The
averaged LED current is well proportional to the duty cycle
of the PWM signal. The internal soft start reduces inrush
current during EN turning on or PWM dimming control.
Other features include OVP, OCP and OTP. OVP prevents
the damages in case of feedback loop open.