UC3845N High-Performance Current Mode PWM Controller

The UC3845N, manufactured by Texas Instruments, is a high-performance current mode pulse-width modulation (PWM) controller that is widely used in switch mode power supplies (SMPS) and DC-to-DC converters. This versatile IC is designed for off-line and DC-to-DC converter applications offering the designer a cost-effective solution with minimal external components.

This device features an onboard oscillator with a programmable frequency range from 100 kHz down to 10 kHz, allowing for flexibility in the design of the power supply. The UC3845N also includes an automatic feed-forward compensation and a pulse-by-pulse current limiting feature which enhances the overall system reliability and performance.

The UC3845N provides several protection features that are crucial for robust power supply design. These include an under-voltage lockout (UVLO) with hysteresis, which ensures that the device only operates when the supply voltage is within an acceptable range. Additionally, the overcurrent protection helps to prevent damage to the IC and connected components in the event of a short circuit or excessive load.

This IC also features a high current totem-pole output that is capable of sourcing and sinking up to 500mA, which is ideal for driving a power MOSFET or IGBT directly. The high-current output minimizes the need for external driver circuits, thereby reducing complexity and cost.

The UC3845N is available in an 8-pin plastic DIP package, making it easy to integrate into various circuit designs. It operates over an extended temperature range, making it suitable for industrial applications. Its performance and features make it an excellent choice for power supply designs that require precise voltage or current regulation, such as in consumer electronics, office equipment, and industrial systems.

Overall, the UC3845N PWM controller from Texas Instruments is a reliable and efficient solution for designers looking to create sophisticated power management systems with a high degree of control and protection.