Full-bridge PWM controller with Integrated MOSFET Drivers

The LM5045 PWM controller contains all

of the features necessary to implement full-bridge topology power converters using

either current mode or voltage mode control. This device is intended to operate on

the primary side of an isolated DC-DC converter with input voltage up to 100V. This

highly integrated controller-driver provides dual 2A high-side and low-side gate

drivers for the four external bridge MOSFETs plus control signals for the

secondary-side synchronous rectifier MOSFETs. External resistors program the leading

and trailing edge dead-time between the main and synchronous rectifier control

signals. Intelligent start-up of the synchronous rectifiers allows monotonic turnon

of the power converter even with prebias load conditions. Additional features

include cycle-by-cycle current limiting, hiccup mode restart, programmable

soft-start, synchronous rectifier soft-start, and a 2MHz capable oscillator with

synchronization capability and thermal shutdown.