UC3845AN

UC3845AN: High-Performance Current-Mode PWM Controller

The UC3845AN is manufactured by a leading semiconductor company and is designed for use in AC-DC and DC-DC converter applications. It operates at a switching frequency of up to 500 kHz, making it suitable for high-efficiency power supply designs.

The controller features a current-mode architecture, which allows for precise control of the output voltage or current based on the sensed current levels. This architecture provides fast transient response and excellent line and load regulation.

The UC3845AN incorporates a trimmed oscillator for precise duty cycle control. The oscillator is temperature-compensated to maintain stable operation over a wide temperature range. This ensures consistent performance and reliability in various environmental conditions.

The controller’s high-gain error amplifier enhances the accuracy of the control loop, providing tight regulation of the output voltage or current. The error amplifier is capable of driving a wide range of loads, making it suitable for various applications.

The UC3845AN also includes a current-sensing comparator that monitors the sensed current levels and compares them to a reference value. This comparator provides the necessary feedback to the PWM latch, ensuring that the output voltage or current is maintained within the desired range.

The controller’s output stage is designed to drive power MOSFETs efficiently. It features a high-current totem pole output that is capable of handling large loads and providing stable operation. The output stage also includes undervoltage lockout (UVLO) protection to prevent damage during low-voltage conditions.

In addition, the UC3845AN offers automatic feed-forward compensation, which simplifies the design of the control loop and improves stability. This feature reduces the need for external compensation components, further reducing cost and complexity in power supply designs.

The UC3845AN is packaged in an 8-pin DIP (Dual-In-Line Package) or SOIC (Small Outline Integrated Circuit) package, making it easy to integrate into various circuits. It is also available in lead-free and RoHS-compliant versions, ensuring compliance with environmental regulations.

Overall, the UC3845AN is a versatile and reliable PWM controller that offers excellent performance and efficiency. Its current-mode architecture, precise duty cycle control, high-gain error amplifier, and robust protection features make it an ideal choice for a wide range of power supply applications.