ON Semiconductor UC2845B High Performance Current Mode Controller

The UC2845B from ON Semiconductor is a high-performance current mode pulse width modulation (PWM) controller that provides all the necessary features to implement fixed frequency, current mode control schemes while maintaining a minimum external parts count. This versatile device is designed to offer improved performance in a variety of power supply applications, including off-line and DC-to-DC converter configurations.

Key Features

• Trimmed Oscillator for Precise Frequency Control: The oscillator frequency is precisely trimmed to ensure accurate and consistent operation, which is crucial for reliable power supply design.
• Oscillator Discharge Current: A consistent and programmable discharge current allows for flexibility in setting the maximum duty cycle, which is beneficial for various applications.
• Current Mode Operation to 500kHz: The device supports high-frequency operation up to 500kHz, enabling compact and efficient power supply designs with smaller passive components.
• Automatic Feed Forward Compensation: This feature helps to maintain stable operation despite variations in input voltage, which is essential for applications that experience fluctuating power conditions.
• Pulse-by-Pulse Current Limiting: Enhanced safety and control are provided through immediate response to overcurrent conditions, protecting both the power supply and the load.
• Enhanced Load Response Characteristics: The UC2845B is designed to react quickly to load changes, ensuring stable output voltage even under dynamic load conditions.
• Under-Voltage Lockout with Hysteresis: This built-in protection feature prevents the device from operating at insufficient supply voltages, which could lead to unpredictable performance or damage.
• Double Pulse Suppression: High-frequency noise immunity is improved with this feature, which helps to prevent false triggering and ensures reliable operation.

Applications

The UC2845B is suitable for a wide range of applications, including:

• Off-Line Power Supplies
• DC-to-DC Converters
• Forward and Flyback Regulators
• Motor Control
• LED Drivers
• Battery Chargers

With its comprehensive feature set and robust design, the UC2845B from ON Semiconductor is an excellent choice for designers looking to create efficient and reliable power management solutions.