The APW7077/A series are multi- function PWM step-up DC-DC converter with an adaptive voltage mode controller and higher efficiency application from one to four cells battery packs. The APW7077/A series are set PWM operating mode, voltage-mode to follow portable application. And built-in driver pin, EXT pin, for connecting to an external transistor or MOSFET during light load, the device will automatically skip switching cycles to maintain high efficiency. The APW7077/A series consists of PW M controller, reference voltage, phase compensation, oscillator, soft-start, driver block. It will provide to operate suitable voltage without external compensation circuit. The APW7077/A series have fixed voltage and adjustable voltage version from a wide input voltage ranges 0.7V to 5.5V for step-up DC-DC converter. The start-up is guaranteed at 1V and the device is operating down to 0.7V. And providing up to 300mA loading current. Besides, low quiescent current (switch-off) is guaranteed.