A NEW dc-to-dc switching power supply controller that combines the functions of three PWM and PSM converter ICs in a single device, has been launched by Siliconix, represented in Australia by Braemac .
Aimed at power conversion applications in consumer appliances, the Si9139 power supply controller takes a 4.5 to 30V input voltage and converts it to three individual, tightly regulated dc-to-dc converter outputs, and one 5V output.
Offering power conversion efficiency in the 95% range, the Si9139 integrates two main synchronous step-down controllers operating at up to 6A, each with seven fixed outputs from 1.5V to 3.3V, and an adjustable step-up/down controller whose output can be set to any value between 1.24V and 20V with an external resistor divider.
This adjustable capability on the third output at 500mA is an industry first for any such device. An on-board 5V, 30mA linear regulator provides an effective fourth output.
The Si9139's two main dc-to-dc outputs provide individual control for power-up sequencing, power-good signal with delay, internal frequency compensation networks, and automatic boot-strapping.
With a 50W power rating, the Si9139 will work efficiently with the most powerful microprocessors and DSPs with ±3% total regulation by line, load, and temperature.
Additional features include internal soft-start and output overvoltage protection and undervoltage shutdown.
Minimal external components are required for a complete solution, for which Vishay delivers the complete bill of materials including PowerPAK and Little Foot power MOSFETs and the three required inductors. No transformer is needed.