STMicroelectronics UC3845A High Performance Current Mode PWM Controller

The UC3845A from STMicroelectronics is a high-performance current mode pulse-width modulation (PWM) controller that provides all the necessary features to implement off-line or DC-to-DC fixed frequency current mode control schemes with a minimal number of external components. This versatile IC is designed for a wide range of power supply applications and is particularly well-suited for use in switch mode power supplies (SMPS), power converters, and various other power control applications.

Key Features

• Optimized for Off-line and DC-to-DC Converters: The UC3845A is tailored for efficient operation in a variety of power conversion scenarios, making it an ideal choice for designers looking to create robust power supplies.
• Low Startup and Operating Current: With its low startup current of 1mA (typical) and operating current of 8.5mA (typical), the UC3845A helps to enhance the efficiency of the overall power supply design.
• Trimmed Oscillator Discharge Current: The oscillator discharge current is trimmed to ensure precise duty cycle clamping, which leads to improved performance and reliability.
• Automatic Feed Forward Compensation: This feature helps in maintaining stable operation over a wide range of input voltages and output powers.
• Pulse-by-Pulse Current Limiting: Enhanced protection is provided by the pulse-by-pulse current limiting feature, which guards the device and the power supply from extreme current overloads.
• Under-Voltage Lockout with Hysteresis: The UC3845A includes an under-voltage lockout with hysteresis to prevent the device from operating at insufficient voltages, thus protecting the circuitry.
• High Current Totem Pole Output: The totem pole output is capable of delivering high peak currents, enabling the direct driving of a power MOSFET or IGBT.
• Double Pulse Suppression: This feature ensures that only one pulse per period is allowed, enhancing the stability and performance of the power supply.

Applications

The UC3845A is suitable for a broad range of applications, including:

• Off-line power supplies
• DC-to-DC converters
• Power factor correction modules
• Battery chargers
• LED drivers
• Telecom power supplies
• Industrial power systems

With its robust design and comprehensive feature set, the UC3845A by STMicroelectronics is an excellent choice for engineers seeking to develop efficient and reliable power supply solutions.