ON Semiconductor UC3845DG High-Performance Current Mode PWM Controller

The UC3845DG from ON Semiconductor is a high-performance fixed frequency current mode controller that is specifically designed for off-line and DC-to-DC converter applications offering the designer a cost-effective solution with minimal external components.

Key Features

• Output Switching Frequency: The UC3845DG operates at a fixed frequency of 500 kHz, which is beneficial for designing efficient power supplies with smaller components and reduced noise.
• High Current Totem Pole Output: The device is capable of delivering a high current output drive capable of sourcing or sinking 1.5 A, which is ideal for driving power MOSFETs or IGBTs directly.
• Trimmed Oscillator Discharge Current: This feature ensures stable and accurate frequency control over temperature and power supply variations.
• Current Mode Operation: Current mode control provides inherent line feed-forward, cycle-by-cycle current limiting and ease of loop compensation.
• Automatic Feed Forward Compensation: This feature helps in maintaining a stable loop performance over a wide range of input voltages.
• Pulse-by-Pulse Current Limiting: Enhanced protection is offered by the UC3845DG through its pulse-by-pulse current limiting functionality.
• Under-Voltage Lockout: With hysteresis, the under-voltage lockout ensures that the controller remains off until the supply voltage reaches an acceptable level.
• Low Startup and Operating Current: The device's low startup (1 mA typical) and operating current (2.5 mA typical) minimize power losses and improve efficiency.

Applications

The UC3845DG is suitable for a wide range of applications, including:

• Switching Power Supplies
• Power Converters
• Motor Controllers
• Battery Chargers
• LED Drivers
• DC-DC Converters

Product Specifications

This PWM controller is available in a 14-pin SOIC package, ensuring compact design possibilities. It operates over an extended temperature range of -25°C to +85°C, making it suitable for various industrial applications.

The UC3845DG by ON Semiconductor is a reliable and efficient choice for designers looking to create robust power management systems with high-level performance requirements.