UC3845BN High Performance Current Mode PWM Controller IC, DIP8

The UC3845BN from STMICROELECTRONICS is a high-performance current mode pulse-width modulation (PWM) controller integrated circuit. It provides all the essential features needed to implement efficient off-line or DC-to-DC fixed frequency current mode control systems with a minimal number of external components. This integration simplifies design and enhances reliability in power supply applications.

Internally, the IC includes a trimmed oscillator for precise duty cycle and frequency control, ensuring stable operation. It features an under-voltage lockout circuit with a start-up current of less than 0.5mA and a precision voltage reference. The architecture incorporates logic for latched operation and a PWM comparator that provides cycle-by-cycle current limiting, offering robust protection for connected power stages.

Key Features

• High Current Output: A totem pole output stage is designed to source or sink high peak currents, making it suitable for driving N-channel MOSFETs efficiently.
• Precision Control: The trimmed oscillator allows for accurate frequency and duty cycle management.
• Enhanced Protection: Features include under-voltage lockout with hysteresis, latching PWM for current limiting, and automatic feed-forward compensation for line regulation.
• Low Power Operation: Designed for low start-up and operating current, improving overall system efficiency.
• Robust Construction: Housed in a through-hole DIP8 package, it is built for durability across a wide operating temperature range from -40°C to 150°C.

This controller is ideal for designing compact and reliable switch-mode power supplies, supporting topologies such as Boost and Flyback converters. Its combination of performance, integrated protection, and ease of use makes it a cornerstone component for advanced power management solutions.