GreenChip Low-Power SMPS Controllers
The NXP TEA172x family is a series of small, low-cost module SMPS controller ICs that operate directly from the rectified universal mains input and are tailored for low-power applications up to 5, 8, or 11 W. Each device is equipped with a high-voltage power MOSFET switch (700 V) and is optimized for flyback, buck, and buck-boost converter topologies. The result is high efficiency over the entire load range. Power consumption in the no-load condition below 10 mW at 5 W, which exceeds the EPA 2.0 rating and the 5-star rating defined by EnergyStar.
The architecture includes several features that serve to reduce total component count, minimize the design footprint, and lower overall cost. Primary side-sensing, which eliminates the need for a power-consuming opto-coupler. The architecture meets EMI specification without an external Y-cap, and integrated active HV start-up eliminates resistor bleeder circuitry. Fewer than 30 external components are required for a complete bill of materials. Advanced control modes enable very high average efficiency (above 77%) over the entire load range, and compliance with USB 1.1 and 1.2 makes them well suited for use in mobile phone charger applications. Switching losses are kept low with a burst frequency of 420 Hz, and a variety of protection features ensure reliable operation under a wide range of conditions.
Design tools for the TEA172x family include a range of demo boards, extensive application notes, and an online calculator that helps predict real-world performance. the entire load range.
The TEA1721 supports operation up to 5 W and is ideally suited for use in mobile USB chargers, major home appliances, and industrial systems. The TEA1722, in development, supports applications up to 8 W and is intended for smartphones and personal consumer products. The TEA1723 runs at up to 11 W and targets tablet PCs, e-readers, and set-top boxes (STBs). All three TEA172x devices have the same feature set but use a different power MOSFET, tailored for operation up to 5, 8, or 11 W, respectively.
The TEA172x architecture provides a circuit for start-up directly from the rectified mains voltage without any external bleeder circuits. The converter operates as a regulated voltage source from no-load up to the maximum output current and operates as a current source that delivers the maximum current over a broad output voltage range.