Full-bridge PWM controllers with integrated MOSFET gate drivers

National Semiconductor has introduced the industry's first full-bridge pulse width modulation (PWM) controllers integrating all four primary-side bridge MOSFET gate drivers. The LM5045 and LM5046 are suggested for designing efficient and power-dense quarter-brick and eighth-brick power supply modules used in a variety of high input voltage communications infrastructure applications.

LM5045 and LM5046 PWM controllers require less external power components compared to existing full-bridge solutions. Watch a phase-shifted full-bridge demonstration featuring the LM5046 at http://bit.ly/LM5045video.

Key technical features:
The LM5045 PWM controller is designed for implement a conventional full-bridge topology power converter using either current mode or voltage mode control.
For applications requiring zero-voltage switching (ZVS) to minimize electro-magnetic interference (EMI) due to switching noise, the LM5046 PWM controller contains all the features necessary to implement a phase-shifted full-bridge topology.
The full-bridge controllers operate on the primary side of an isolated DC-DC converter with input voltage up to 100V.
These controllers can provide 2A high and low side gate drivers for the four external bridge MOSFETs in addition to the control signals for the secondary side synchronous rectifier MOSFETs and an internal high voltage start-up regulator.
Intelligent startup of the synchronous rectifiers (SR) allows monotonic turn-on of the power converter, even with pre-bias load conditions.
The synchronous rectifier control signals offer independent and programmable leading/trailing edge dead-times between the primary and secondary MOSFET control signals for optimizing efficiency, and the SR signals are limited to 5V for use with digital isolators.
Additional features include dual mode over-current protection featuring both cycle-by-cycle current limiting and hiccup mode restart, programmable soft-start, timing for both primary and synchronous rectifiers, programmable line UVLO and OVP, a synchronizable 2 MHz oscillator and thermal shutdown.

National suggests its new LM5045 and LM5046, together with secondary side FET drivers such as the LM5110, LM5111 and LM5112, provide a complete controller solution to implement a highly efficient, small form factor full-bridge power converter.

For more information on the LM5045
visit http://www.national.com/pf/LM/LM5045.html.
For more information on the LM5046 visit http://www.national.com/pf/LM/LM5046.html.

Package: 5.0 mm by 5.0 mm by 0.8 mm LLP and 4.4 mm by 9.7 mm by 0.9 mm TSSOP packages

Availability: Now

Price:
LM5045: Each US$2.25 for 1K pieces
LM5046: Each US$2.45 for 1K pieces