Unitrode UCC38500NL

Description

The UCC38500NL is an advanced power management IC designed to integrate power factor correction (PFC) and a downstream DC-DC converter controller into a single package. This high-performance controller achieves near-unity power factor by shaping the AC input current to match the AC input voltage using an average current-mode control method. The device also includes a secondary-stage DC-DC converter that employs peak current-mode control for efficient step-down voltage regulation.

By incorporating leading-edge modulation in the PFC stage and trailing-edge synchronization in the secondary stage, the UCC38500NL minimizes ripple current in the bulk output capacitor, enhancing system stability and efficiency. It features built-in line feedforward regulation to maintain consistent input power across varying input voltage levels. Additionally, the device integrates essential protections such as over-voltage protection, current limiting, and zero-power detection to ensure safe operation.

The UCC38500NL is available in 20-pin packages and is ideal for high-efficiency power supply designs requiring active PFC and DC-DC conversion.

Features

• Integrated PFC and DC-DC Converter Control – Combines two essential power management functions in one IC
• Near-Unity Power Factor – Uses average current-mode control to shape input current
• Precise Power Limiting – Ensures accurate power management and regulation
• Enhanced Line Feedforward Regulation – Maintains stable input power despite voltage fluctuations
• Peak Current-Mode Control – Improves efficiency and stability in the DC-DC conversion stage
• Customizable Oscillator Frequency – Allows tuning for various applications
• Leading-Edge and Trailing-Edge Modulation – Reduces output ripple and improves power efficiency
• Low Startup Current – Enhances energy efficiency in power-up conditions
• Programmable Soft-Start – Ensures controlled startup of the secondary stage
• Configurable Shutdown Mode – Allows flexible power management

Types

The UCC38500NL belongs to the UCC38500 family, which includes different variations optimized for specific applications:

• UCC38500NL – Standard version with integrated PFC and DC-DC control
• UCC28500 – Wide UVLO threshold (16.5V/10V) for bootstrap bias supply applications
• UCC28501 – Narrow UVLO threshold (10.5V/10V) for fixed bias applications
• UCC28502 – Wide operating range for the PWM stage, supporting lower input voltages
• UCC28503 – Similar to UCC28502 but with alternative UVLO configurations

Each variant is designed to provide optimized performance based on system voltage and control requirements.

Applications

The UCC38500NL is widely used in applications requiring high efficiency and power factor correction, including:

• Switched-Mode Power Supplies (SMPS) – Ensures efficient AC-DC conversion with active PFC
• Industrial Power Supplies – Used in high-power equipment with strict power regulation needs
• Telecommunications Power Systems – Provides stable and efficient power for network infrastructure
• Computing and Server Power Supplies – Improves power factor in high-performance computing environments
• Consumer Electronics – Used in appliances and devices requiring active PFC for energy efficiency
• LED Drivers – Enhances performance and efficiency in LED lighting systems

With its integrated design and advanced control features, the UCC38500NL is an excellent choice for applications demanding precise power regulation and high efficiency.