Step-down controller

Vishay has released a triple-output step-down controller IC designed for power conversion in set-top boxes, base stations, wall adapters, consumer electronics and network intermediate bus DC input supplies.

The SiP12203 provides all the required control circuitry and protection features for two switching step-down power rails, and one linear power output, in a broad range of applications including DSP, ASIC and FPGA supplies and dual supply microprocessor and DSP cores.

The synchronous buck architecture allows voltages to be converted with efficiency up to 94%. The device features an input voltage range of 4.5 to 18, with two independent outputs offering adjustable voltages down to 0.6 and 180° out-of-phase operation for reduced EMI and RMS input current.

The IC’s third output is a built-in LDO controller that controls a discrete p-channel MOSFET in linear mode for up to 1 A output.

The device reduces the number of required external components to simplify the design layout. It drives two external n-channel MOSFETs per channel, instead of one n-channel and one p-channel device. The 500 kHz operating frequency, which can be synchronised with an external source, enables the use of smaller passive components in converter designs.

The device incorporates several protection features, including an adjustable overvoltage protection circuit that monitors the output current by sensing the voltage drop across the lower MOSFET, protecting the DC-DC components from damage during output overload/short circuit conditions.

It also includes independent enable, current limit, feedback compensation and internal soft start functions for each output.