Provides intelligent digital control and unique body diode sensing capability

TI has released the industry's first power management chipset offering intelligent digital control and unique body diode sensing functionality.

Through these features, the chipset optimizes secondary-side synchronous rectification for next-generation AC/DC and isolated DC/DC power supplies.

The UCD3138A digital controller and UCD7138 low-side gate driver increase system efficiency compared to other digital power solutions and reduce synchronous rectifier MOSFET voltage stress by half.

Precise dead time control in synchronous rectifiers minimizes power losses and reduces the risk of MOSFET failure.

The UCD3138A and UCD7138 chipset dynamically optimizes dead time by using body diode voltage information with fast digital control algorithms, and compensates for differences in power stage components during mass production without calibration or screening.

As a result, telecommunications and server equipment manufacturers can more easily bring to market power supplies meeting 80 PLUS Titanium energy efficiency ratings, and IT service providers can reduce energy costs.

Lee Won-seop, Director at TI, stated that application targets for the UCD7138 and UCD3138 are products in the tens to hundreds of kilowatts or higher range, noting that "even a small efficiency improvement of about 0.5% in these applications can bring significant changes to power consumption."

Key Features and Advantages

Optimizes dead time through intelligent diode voltage sensing functionality. By adjusting timing to minimize diode conduction, it enhances efficiency and reliability while eliminating noise issues inherent in conventional MOSFET VDS ON sensor devices.

High peak current supports a wide load range. The UCD7138's asymmetric, rail-to-rail 4A source and 6A sink peak current drive support load ranges from hundreds of watts to 1 kilowatt when using multiple parallel FETs.

Ultra-compact solution realizes fast and efficient switching performance. With the industry's smallest 3mm x 3mm QFN package, it handles large currents and reduces parasitic inductance and saves board space when placed adjacent to synchronous rectifier MOSFETs.

Operates efficiently at frequencies up to 2MHz. Combined with UCD3138A's hardware peripherals, the UCD7138's 14ns propagation delay, fast rise/fall times, and minimized tolerance allow very high frequency operation.

TI has recently released a new solution alongside these chipsets for lower-power AC/DC flyback converters. The new UCC24630 synchronous rectifier controller provides maximum efficiency with low sensitivity to board layout and MOSFET package parasitic elements.

Additionally, automatic light-load detection functionality and 110uA standby current enable developers to easily achieve very low standby power consumption.

Tools and Support

Developers can rapidly develop and debug applications using TI's CCS (Code Composer Studio) integrated development environment (IDE). Furthermore, developers can reference the TI Designs 340W digital control LLC resonant half-bridge DC/DC power conversion reference design.


The UCD3138A and UCD7138 devices are currently available from the TI store and authorized TI distributors. The UCD7138 MOSFET driver is offered in a 6-pin QFN package at a price of $1.10 for quantities of 1,000 units. The UCD3138A digital controller is offered in a 40-pin QFN package at a price of $3.22 for quantities of 1,000 units.