Digital Controller Eases Design of Isolated Power Supplies

Mar 12, 2008 5:26 PM

by David Morrison, Editor-in-Chief, Power Electronics Technology

A digital power controller developed by Analog Devices to implement isolated power converters aims to provide the same ease-of-use that until now was only available with digital power controllers for nonisolated converters. The ADP1043 targets isolated ac-dc power supplies and dc-dc converters used in high-reliability server, storage, and communications infrastructure equipment. The key to the controller’s ease-of-use is a graphical user interface (GUI) that designers can use to configure and program the controller.

The GUI is said to allow one designer to quickly use a single IC to support multiple power supply designs. According to the company, the GUI is very intuitive and requires no programming skills. Moreover, the GUI is said to be highly interactive.

Power design engineers with no prior programming experience can use the GUI to monitor and quickly adjust power functions such as frequency, timing, voltage settings and protection limits. In end-system implementations, the ADP1043 helps system integrators optimize power supply efficiency, while reducing design cycle time and enabling intelligent power management systems.

Unlike existing DSP-based digital controllers, the ADP1043 is an “application-dedicated digital controller,” says Laurence McGarry, marketing manger for Analog Devices’ Power Management Products Division. This type of design is akin to the state-machine based approach used in some of the nonisolated digital power controllers, says McGarry. McGarry notes that it’s much easier to have a GUI “wrapped around” this type of controller versus the DSP-based approach.

The ADP1043 will be competing against the DSP-based controllers for use in isolated power supply designs, but also against the traditional analog power controllers.

The ADP1043 integrates technology for isolated power conversion, housekeeping, and monitoring. Features include a 7-output PWM; on-board memory for program and data storage; the choice of traditional analog or digital current-share schemes for parallel power supply operation; and MOSFET “OR-ing” control for redundant power supply operation (an analog function). In addition, the chip provides differential voltage sensing and trimming (see Figure 1).

Configuration of the controller’s adjustable parameters and features is accomplished via an I2C interface, which also enables monitoring of various diagnostic measurements. These include power, current, voltage, and temperature. In addition, the chip offers status and first-failure flag recording.

Because the ADP1043 was defined before the PMBus standard, the controller isn’t PMBus compatible. However, McGarry notes that a future version will be compatible with the standard.

The controller supports most power supply topologies including forward converter types such as single ended, active clamp, and interleaved forward. It also supports push-pull, half- and full-bridge topologies; and two-stage dc-dc converters.

The ADP1043 will be available for general sampling in May 2008 and in production quantities in August 2008. The ADP1043 is priced at $4.50 per unit in 1000-piece quantities and comes in a 5-mm x 5-mm, 32-pin LFCSP package. For more information, visit www.analog.com.