Texas Instruments

UC1825J

The UC1825J is a high-voltage, fixed-frequency, current mode step-down switching regulator controller produced by Texas Instruments. It is designed for use in off-line applications, such as power supplies for desktop computers, monitors, and other high-voltage equipment.

Description:

The UC1825J is a monolithic integrated circuit that provides all the necessary features for a step-down switching regulator, including a high-voltage power MOSFET driver, error amplifier, oscillator, and reference voltage source. It operates with an input voltage range of up to 500V and can provide an output voltage as low as 1.2V.

Features:

1. Fixed 100 kHz switching frequency
2. High-voltage operation up to 500V
3. Internal soft-start and burst mode for improved efficiency at light loads
4. Over-current protection
5. Over-temperature protection
6. Under-voltage lockout
7. External compensation for stability with a wide range of output capacitors
8. Thermal shutdown protection
9. External sync input for frequency synchronization with other regulators

Applications:

1. Desktop computer power supplies
2. Monitor power supplies
3. High-voltage off-line power supplies
4. Industrial power supplies
5. Telecommunications power supplies
6. Medical power supplies

The UC1825J is a versatile and reliable choice for designers looking to implement a high-voltage, step-down switching regulator in their off-line applications. Its fixed switching frequency, soft-start, and burst mode features help to improve efficiency and reduce EMI, while its over-current, over-temperature, and under-voltage protection features ensure safe and reliable operation.