“First” controller ICs to integrate 75V half-bridge MOSFET drivers with 1.6A peak current

The Siliconix SiP11205 and SiP11206 controller ICs are for intermediate bus converter (IBC) applications that are the first such single-chip devices on the market to integrate high-voltage (75V) half-bridge MOSFET drivers with a 1.6A peak current driving capability, as well as a full range of current monitoring and control features.

The controllers are designed to work on the primary side of an isolated half-bridge IBC in telecom and network equipment and in 1/16 or 1/8 power modules where standard bus voltages such as 48V need to be converted to 12V or lower intermediate voltages. They simplify designs and reduce solution costs by eliminating the need for separate controller and high-voltage MOSFET driver components for secondary synchronous rectification, while their half-bridge architecture further reduces costs and space requirements by enabling the use of lower-voltage components.

The SiP11205 and SiP11206 controllers step down voltages with more than 95 percent efficiency. They feature an input voltage range of 36V to 75V and comfortably handle 100V transients for 100ms in compliance with ETSI 300-132-2. Integrated ±1.6A high-voltage MOSFET drivers allow each IC to drive both the low- and high-side switching devices in a half-bridge converter. The oscillator frequency is programmable from 200kHz to 1MHz, the widest such range in the industry, and can be synchronized to an external sync source. Self-driven synchronous rectification eliminates the requirement for secondary-side MOSFET drivers and isolated pulse drivers, reducing costs and simplifying designs.

The SiP11205 features input-voltage sensing and feed-forward circuitry that keep the output voltage within a tight range without the use of opt couplers or voltage feedback circuitry. The SiP11206 differs by allowing the converter to work at the optimal duty cycle within its full input voltage range in DC transformer mode, which greatly improves system efficiency.

The SiP11205 and SiP11206 offer a comprehensive range of protection features. The controller supply voltage is linearly regulated up to its target voltage with an on-chip pre-regulator circuit. Advanced current monitoring and control circuitry allow the user to set the maximum current in the primary circuit. The controllers are protected against overcurrent conditions, output short circuits, and errors when paralleling power supplies. Additional features include low input-voltage detection, programmable soft-start, and overtemperature protection.