PWM controller, Texas Instruments
TI intermediate bus PWM controller increases energy efficiency over entire load range
News Release from:
28 May 2008
Texas Instruments has introduced a power supply controller for unregulated output voltages that achieves up to 97 percent system efficiency in an intermediate bus architecture. The controller allows intermediate bus architecture power systems to combine the highest amount of energy savings, high power-density and low system costs in telecom and data communication systems with multiple downstream point-of-load conversions.
The integrated UCC28230 PWM controller supports both the half-bridge and full-bridge topologies and reduces overall size and the need for external components. Designers can set the operation to work in a fixed volt-second or fixed frequency mode, which reduces the size of the transformer.
The UCC28230 has a start-up frequency control feature that limits output inductor ripple current, allowing the use of a smaller, inexpensive inductor. The UCC28230 implements load-dependent dead-time control to improve efficiency over the entire output load range. It also has 1-D output that shorts the primary-side winding, which keeps the self-driven synchronous rectifiers under control during start-up and shut-down and through transient conditions. Additionally, the UCC28230 provides state-of-the-art protection features, such as input under-voltage lockout, thermal shutdown protection and cycle-by-cycle over-current protection.
The UCC28230 includes a precision 5-V reference voltage output for general-purpose voltage biasing. In addition, the UCC28231 includes a precision 3.3-V reference voltage output for the same purpose. For added flexibility, the controller can be paired with TI’s UCC27200 dual high-side, low-side driver to drive MOSFETs for half- and full-bridge topologies.
The UCC28230 intermediate bus controller can also be used in high-voltage applications such as DC/DC transformers, and it serves as a downstream converter when paired with TI’s UCC28070 interleaved PFC controller.