Unique body diode sensing improves system efficiency
and cuts MOSFET voltage stress in half
Texas Instruments (TI) today announced the industry's first power management chipset with intelligent digital control and unique body diode sensing to optimize secondary-side synchronous rectification in next-generation AC/DC power supplies. by up to half compared to other digital power solutions.
Precise control of dead time within the synchronous rectifier minimizes power loss while reducing the risk of MOSFET power failures. the UCD3138A and UCD7138 chipsets use body diode voltage information in a fast digital control algorithm to dynamically optimize dead time and can compensate for power stage component variations, eliminating the need for calibration or screening in volume production. This can help server and telecom equipment vendors accelerate time to market for 80PLUS Titanium Gold certified power supplies, while also helping IT service providers save on energy costs.
Key features and benefits of the UCD3138A and UCD7138.
● Smart diode voltage sensing optimizes dead time: more accurate detection of parasitic diode conduction in synchronous rectifiers improves efficiency and reliability while eliminating the signal-to-noise challenges of traditional MOSFET VDS ON sensing devices.
● High peak current support for wide load ranges: The UCD7138's asymmetrical, rail-to-rail 4 A supply current and 6 A peak absorption current drive supports load ranges from a few hundred watts to one kilowatt when using multiple parallel FETs.
● Compact solution for fast, efficient switching: A single 3 mm x 3 mm quad flat leadless (QFN) package reduces board-level space and reduces parasitic inductance when placed next to a synchronous rectifier MOSFET.
Efficient operation at frequencies up to 2 MHz: The hardware peripherals in the UCD3138A and the 14 ns propagation delay, fast rise/fall times and minimized tolerances in the UCD7138 enable extremely high frequencies.
In conjunction with this chipset, TI has also recently released new lower power AC/DC Flyback converters. TI's UCC24630 synchronous rectifier controller provides the highest efficiency and low sensitivity to board layout and MOSFET package parasitic effects. In addition, automatic low-power detection and 110μA standby current also allows designers to easily achieve ultra-low standby power consumption.