The R1205x Series are CMOS-based PWM control type step-up DC/DC converter ICs with low supply current.
Each of these ICs consists of an NMOS FET, a diode, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP), a soft-start circuit, a Maxduty limit circuit, and a thermal shutdown protection circuit. This step-up DC/DC converter can be easily built with a few external components such as a coil, a resistor, and a capacitor.
As the protection functions, the R1205x Series have a Lx peak current limit function, an over voltage protection (OVP) function, an under voltage lock out (UVLO) function and a thermal shutdown function.

The R1205x Series present the R1205x8xxA version that is optimized for the constant voltage power source, and the R1205x8xxB version that is optimized for driving the white LED with the constant current. The R1205x8xxB is an adjustable version that can change the LED brightness dynamically by using a 200Hz to 300kHz PWM signal toward the CE pin.

The R1205x Series are available in DFN1616-6B and TSOT-23-6 packages.