TheAPW8822/A/B/C integrates dual step-down, constanton-time, synchronous PWM controllers (that drives dual N-channel MOSFETs for each channel) and two low dropout regulators as well as various protections into a chip. The PWM controllers step down high voltage of a battery to generate low-voltage for NB applications. The output of PWM1 and PWM2 can be adjusted from 2V to 5.5V by setting a resistive voltage-divider from VOUTx to GND. The linear regulators provide 5V and 3.3V output for standby power supply. The linear regulators provide up to 100mA output current. When the PWMx output voltage is higher than LDOx bypass threshold, the related LDOx regulator is shut off and its output is connected to VOUTx by internal switchover MOSFET. It can save power dissipation. The charge pump circuit with 270kHz clock driver uses VOUT1 as its power supply to generate approximately 15V DC voltage. The APW8822/A/B/C provides excellent transient response and accurate DC output voltage in either PFM or PWM Mode. In Pulse-Frequency Mode (PFM), the APW8822/A/B/C provides very high efficiency over light to heavy loads with loading-modulated switching frequencies. The Forced-PWM Mode works nearly at constant frequency for low-noise requirements. The unique ultrasonic mode maintains the switching frequency above 25kHz, which eliminates noise in audio application