60V Synchronous Buck Controller Takes Two Steps Down at Once

The easy-to-use ISL8117, launched by Intersil, is the first 60V synchronous buck PWM controller able to bypass the intermediate step-down conversion stage traditionally employed in industrial applications. Its low duty cycle (40ns minimum on time) enables the direct step-down conversion from 48V to a 1V point-of-load voltage. This technical achievement makes it possible for designers to reduce system complexity and solution cost in industrial, factory automation, medical and communications infrastructure applications.

In high voltage applications where a lower output voltage is required, designers have traditionally relied on modules that increase system cost, or two-stage DC/DC solutions that increase solution footprint and complexity. The ISL8117 controller offers a cost-effective and reliable alternative for applications where Vout to Vin ratio is low. It uses valley current mode modulation with adaptive slope compensation to enable stable operation for a wide range of Vin and Vout combinations, with no external compensation required. System designers can also use the adjustable frequency up to 2 MHz to optimize power supply cost, size and efficiency.

The innovative synchronous buck PWM controller reduces solution footprint and simplifies design without compromising performance. Default design values for commonly used functions and the wide Vin and Vout reduce the number of external components compared to competing solutions. With the new controller, engineers can design a complete DC/DC buck conversion solution with only 10 components, including MOSFETs and passives, and achieve up to 98% conversion efficiency with 1.5% output voltage accuracy. The low pin count and layout friendly pin architecture also minimizes the number of overlapping traces, further improving power supply performance.

“The ISL8117 buck controller addresses a growing need for direct POL conversion from very high input voltage such as 48V to 1V output,” said Mark Downing, senior vice president of Infrastructure and Industrial Power Products at Intersil. “The unique ability to support light load efficiency mode is critical in industrial applications and makes the ISL8117 a much better alternative than existing solutions based on older technology.” 

The 60V synchronous buck PWM controller has the following key features and specifications:

• Wide input voltage range of 4.5V to 60V covers all standard input rails including 5V, 12V, 24V, 36V, 42V and 48V;
• Wide voltage output range is configurable from 0.6V to 54V;
• Smallest minimal on-time in the market, which enables a very low duty cycle power supply and eliminates the need for a two stage solution in many applications;
• Programmable100kHz to 2Mhz switching frequency can be synchronized to reduce radiated system noise and avoid beat frequency issues;
• Complete fault protection for long term reliability including over-voltage, under-voltage, over-current and over-temperature;
• High current FET drivers and DEM mode operation ensures efficiency at all load levels;
• Adjustable soft-start with pre-bias support enables the sequenced startup of multiple ISL8117 controllers.

​The high voltage controller can be combined with Intersil´s low drop-out linear regulators such as the ISL80136, ISL80138, ISL80101A, and integrated FET switching regulators (ISL8023/24 or ISL8016) to support the bulk power rails in a typical process control industrial application.

The ISL8117 is available now in 4mm x 4mm QFN and 6.4mm x 5mm HTSSOP packages. Two evaluation boards allow designers to quickly evaluate device features and performance: ISL8117EVAL1Z low power (Vin 4.5V-60V and 3.3Vout/6A), and the ISL8117EVAL2Z high power (Vin 18V-60V and 12Vout/20A). Two demonstration reference design boards allow to produce low power (factory automation or robotic) and high power (telecom or pachinko) applications.

About Intersil

Intersil Corporation, a wholly owned subsidiary of Renesas Electronics Corporation, is a leading provider of innovative power management and precision analog solutions. The company's products form the building blocks of increasingly intelligent, mobile and power hungry electronics enabling advances in power management to improve efficiency and extend battery life. With a deep portfolio of intellectual property and a rich history of design and process innovation, Intersil is the trusted partner to leading companies in some of the world's largest markets, including the industrial and infrastructure, mobile computing, automotive and aerospace.