Torex develops dual output step-up/inverting DC/DC converter

Torex Semiconductor Ltd has developed the XC9519 series, a 2-channel step-up/inverting DC/DC converter. The device can be set up to 18V, while the inverting DC/DC converter can be set down to -15V. Small external components can be used because the of its 1.2MHz switching frequency.

The input voltage range of the XC9519 series is 2.7V to 5.5V. The output current is 500mA (V_IN=3.7V, V_OUTP=5.0V, V_OUTN=-5.0V). PWM control and automatic PWM/PFM switching control can be selected for the operation modes. The switching frequency of PWM control is fixed, thereby reducing noise. Automatic PWM/PFM switching control switches from PWM control to PFM control when the load is light to achieve high efficiency across the entire load range, from light loads to high output currents.

The step-up DC/DC converter has a built-in soft start time of 2.5ms (TYP.), while the inverting DC/DC converter's soft start time is 2.2ms (TYP.). The supply current is 1.0?A or less in standby. A gate control circuit for an external P-channel MOSFET for load cutoff is incorporated. By adding an external P-channel MOSFET, the load can easily be cutoff in standby.

Protective circuits include driver Tr current limiting (2A MIN) and thermal shutdown. A UVLO function that forces the driver Tr off at an input voltage of 2.2V or less is also incorporated. The IC is housed in a small QFN-24 (4.0 × 4.0 × h0.8mm) package.