New Industry Products

Zero-Standby Power PSR Solution for AC-DC Power

March 05, 2015 by Jeff Shepard

Texas Instruments, Inc. (TI) today claimed the industry's first zero standby power (as defined in International Electrotechnical Commission (IEC) 62301 clause 4.5) controller chipset with the lowest standby power consumption for standard flyback designs up to 20 W and is extendable up to 75 W using the intelligent sleep function for adaptive relay control. The new UCC28730 primary-side regulation (PSR) flyback controller with 700-V startup switch and UCC24650 wake-up monitor supports 5- to 24-V output voltages and helps designers create smaller, more efficient power supplies for TVs; home appliances; ac adapters; heating, ventilation and air conditioning (HVAC); and building automation systems.

A design challenge with existing primary-side regulation power supplies today is poor transient response performance while trying to maintain low standby power. The UCC28730 and UCC24650 chipset achieves zero standby power consumption while achieving the best transient response performance possible. Besides reducing cost by eliminating feedback components such as an optocoupler and TL431, TI’s voltage droop-detection feature in the UCC24650 wake-up controller enables the use of tiny output capacitors while maintaining a narrow-output voltage-regulation window with zero- to full-load transients.

Additional features and benefits of the UCC28730 and UCC24650: Smart wake-up function: Enables 50 percent lower output capacitors while maintaining a tight output regulation window with zero to full load steps, improving efficiency and saving space. Intelligent sleep function: Adapts to converter-loading conditions and is able to disable system functions, adapt for ac relay control, or disable the synchronous rectifier at no load. 200-V secondary-side wake-up controller (UCC24650): Compatible with 5- to 24-V output voltage designs without the need for external clamps on Vdd or wake.

Both products are shipping in volume production and available for ordering through the TI Store and the company’s authorized distribution network. The UCC28730 flyback controller comes in a seven-pin small outline integrated circuit (SOIC) package and is priced at US$0.45. The UCC24650 comes in a five-pin small-outline transistor (SOT)-23 package and is priced at US$0.14 in 1,000-unit quantities.