Texas Instruments

UC1843J

The Texas Instruments UC1843J is a high-voltage, fixed-frequency current mode controller designed for offline switch-mode power supply (SMPS) applications. It is particularly suitable for use in universal input and high-voltage output power supplies.

Description:

The UC1843J is a monolithic integrated circuit that provides all the necessary functions for a current mode controller. It includes an error amplifier, a driver for the power switch, a current sensing comparator, and a fixed-frequency oscillator. The device is available in a small-outline integrated circuit (SOIC) package.

Features:

1. Fixed 40 kHz switching frequency: This allows for smaller-sized components and simpler EMI filtering.
2. Universal input voltage range: The UC1843J can operate with input voltages ranging from 85V to 265V, making it suitable for both AC and DC applications.
3. Overcurrent protection: The device provides overcurrent protection to prevent damage to the power supply in case of a short circuit or overload.
4. Overvoltage protection: The UC1843J includes overvoltage protection to protect the output from voltage spikes.
5. Undervoltage lockout: This feature prevents the power supply from operating if the input voltage is too low.
6. Thermal shutdown: The device will shut down if the temperature exceeds a safe operating limit, protecting the power supply from overheating.
7. Burst mode operation: This feature allows the power supply to operate in a low-power mode when the load is light, improving efficiency.

Applications:

The UC1843J is suitable for a wide range of power supply applications, including:

1. Desktop and laptop computer power supplies
2. Telecom power supplies
3. Industrial power supplies
4. Medical power supplies
5. LED lighting power supplies
6. TV and monitor power supplies
7. Audio and video power supplies

In summary, the Texas Instruments UC1843J is a versatile and reliable current mode controller for switch-mode power supply applications. Its fixed-frequency operation, universal input voltage range, and comprehensive protection features make it a popular choice for designers looking to create efficient and reliable power supplies.