ON Semiconductor UC3842BD Current Mode PWM Controller

The UC3842BD from ON Semiconductor is a high-performance current mode pulse width modulation (PWM) controller that is widely used in AC to DC and DC to DC converters. This integrated circuit is designed to offer low power consumption and improved system reliability, making it an excellent choice for power supply designers.

Key Features

• Optimized for Off-line and DC to DC Converters: The UC3842BD is tailored for various converter topologies, including boost, buck, flyback, and forward converters.
• Low Startup and Operating Current: This device features a low startup current of typically 0.5 mA and a low operating current of typically 8.5 mA, contributing to the efficiency of the power supply.
• Automatic Feed Forward Compensation: It offers excellent line regulation by compensating for variations in input voltage without the need for external components.
• Pulse-by-Pulse Current Limiting: Enhanced protection is provided by the current mode operation, which ensures that the peak current in the power switch is controlled on a pulse-by-pulse basis.
• Under-Voltage Lockout with Hysteresis: The built-in under-voltage lockout feature with hysteresis ensures that the device is off when the supply voltage is insufficient, thus protecting the circuit components.
• High Current Totem Pole Output: The output stage can source or sink high peak currents, making it suitable for directly driving a power MOSFET or IGBT.
• Trimmed Oscillator for Precise Frequency Control: The oscillator frequency is trimmed to a tight tolerance, which is critical for consistent performance in power supply applications.

Applications

The UC3842BD is versatile and can be used in a variety of applications, including:

• Switching power supplies
• Power converters for personal computers
• Industrial power systems
• DC-DC modules
• Battery chargers

Overall, the UC3842BD PWM controller from ON Semiconductor is a robust and reliable solution for power management challenges in a broad range of electronic systems. Its combination of features ensures efficient operation, reduced component count, and high performance in power supply circuits.