TI’s LM5045″ title=”LM5045″>LM5045 is a full-bridge topology PWM power control converter chip that can realize current mode or voltage mode. This chip mainly solves the problem of primary isolation DC-DC with a maximum input voltage of 100V. Converter. It has the characteristics of current limit, programmable soft start, synchronous rectification soft start and thermal shutdown. This article first introduces the introduction, characteristics and internal block diagram of the chip, and gives the design schematic diagram, component list and component list of the corresponding design scheme. PCB component layout diagram.

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 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 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.

Main features of LM5045:

2• Highest Integration Controller for Small Form Factor, High Density Power Converters
• High Voltage Start-up Regulator
• Intelligent Sync Rectifier Start-up Allows Linear Turn-on into Pre-biased Loads
• Synchronous Rectifiers Disabled in UVLO mode and Hiccup Mode
• Two Independent, Programmable Synchronous Rectifier dead-time Adjustments
• Four High Current 2A Bridge Gate Drivers
• Wide-Bandwidth Opto-coupler Interface
• Configurable for either Current Mode or Voltage Mode Control
• Dual-mode Over-Current Protection
•Resistor Programmed 2MHz Oscillator
• Programmable Line UVLO and OVP

TILM5045 DC power conversion evaluation reference design
Figure 1. LM5045 internal block diagram

LM5045 program introduction:

The LM5045 evaluation board is designed to provide the design engineer with a fully functional power converter based on the full-bridge topology to evaluate the LM5045 PWM controller. The evaluation board is provided in an industry standard quarter brick footprint.

The performance of the evaluation board is as follows:

• Input operating range: 36V to 75V
• Output voltage: 3.3V
• Measured efficiency at 48V: 92% @ 30A
• Frequency of operation: 420kHz
• Board size: 2.28 x 1.45 x 0.5 inches
• Load Regulation: 0.2%
• Line Regulation: 0.1%
• Line UVLO (34V/32V on/off)
• Hiccup Mode Current Limit

The printed circuit board consists of 6 layers; 2 ounce copper outer layers and 3 ounce copper inner layers on FR4 material with a total thickness of 0.062 inches. The unit is designed for continuous operation at rated load at <40°C and a minimum airflow of 200 LFM.

TILM5045 DC power conversion evaluation reference design

LM5045 scheme schematic diagram:

Figure 2. Schematic diagram of the LM5045 solution

LM5045 program material list:

TILM5045 DC power conversion evaluation reference designTILM5045 DC power conversion evaluation reference design

PCB component layout diagram:

TILM5045 DC power conversion evaluation reference designTILM5045 DC power conversion evaluation reference design

TILM5045 DC power conversion evaluation reference design
TILM5045 DC power conversion evaluation reference designTILM5045 DC power conversion evaluation reference design
TILM5045 DC power conversion evaluation reference designTILM5045 DC power conversion evaluation reference design

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