Part Number: LM5045
Function: Full-Bridge PWM Controller with Integrated MOSFET Driver
Package: 28 HTSSOP / 28 WQFN Type
Manufacturer: Texas Instruments
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Description
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 and low side gate drivers for the four external brige 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 startup of the synchronous rectifiers allows monotonic turn-on of the power converter even with pre-bias load conditions.
Additional features include cycle-by-cycle current limiting, hiccup mode restart, programmable soft-start, synchronous rectifier soft-start and a 2 MHz capable oscillator with synchronization capability and thermal shutdown.
Pinouts
Features
- Full-bridge PWM controller for isolated DC-DC converters
- Supports both current-mode and voltage-mode control
- Integrated four 2A gate drivers for primary-side MOSFETs
- Control outputs for secondary-side synchronous rectifiers
- Wide input operation up to 100V
- High-frequency operation up to 2 MHz with synchronization capability
- Programmable soft-start and synchronous rectifier soft-start
- Cycle-by-cycle current limiting
- Hiccup mode fault protection for overload conditions
- Thermal shutdown protection
- Integrated high-voltage startup regulator
Design Notes
- Full-bridge topology enables efficient power conversion at higher power levels (>100W typical)
- Dead-time programming is critical to prevent shoot-through in MOSFETs
- Synchronous rectification significantly improves efficiency in low-voltage outputs
- Current-mode control simplifies loop compensation and provides inherent overcurrent protection
- Transformer design (turns ratio, leakage inductance) is key for efficiency and EMI
- Layout must minimize high di/dt loop areas (primary switching loop and gate drive loop)
- Proper snubber or clamp circuits may be required to handle voltage spikes
Typical Applications
- Isolated DC-DC converters (industrial power supplies)
- Telecom and server power systems
- High-density power modules
- Battery-powered high-power systems
- Electric vehicle auxiliary power supplies
Advantages
- High level of integration reduces BOM and design complexity
- Supports advanced topologies (full-bridge + synchronous rectification)
- Robust protection features improve system reliability
- Flexible control (current-mode / voltage-mode)
- Suitable for high-efficiency, high-density designs
Alternative / Equivalent Products
- UCC28950 – Phase-shifted full-bridge controller (TI)
- UC3825 – PWM controller for bridge topologies
- NCP1397 – ON Semiconductor resonant controller
- ICE2HS01G – Infineon half/full-bridge controller
- SG3525 – Classic PWM controller (less integrated)
Other data sheets are available within the file:
LM5045MH, LM5045MH/NOPB, LM5045MHX, LM5045MHX/NOPB
LM5045 Datasheet PDF Download
