The UC2577-ADJ device provides all the active functions necessary to implement step-up (boost), flyback, and forward converter switching regulators. Requiring only a few components, these simple regulators efficiently provide up to 60V as a step-up regulator, and even higher voltages as a flyback or forward converter regulator.
The UC2577-ADJ features a wide input voltage range of 3.0V to 40V and an adjustable output voltage. An on-chip 3.0A NPN switch is included with undervoltage lockout, thermal protection circuitry, and current limiting, as well as soft start mode operation to reduce current during startup. Other features include a 52kHz fixed frequency on-chip oscillator with no external components and current mode control for better line and load regulation.
A standard series of inductors and capacitors are available from several manufacturers optimized for use with these regulators and are listed in this data sheet.
Requires Few External Components
NPN Output Switches 3.0A, 65V(max)
Extended Input Voltage Range: 3.0V to 40V
Current Mode Operation for Improved Transient Response, Line Regulation, and Current Limiting
Soft Start Function Provides Controlled Startup
52kHz Internal Oscillator
Output Switch Protected by Current Limit, Undervoltage Lockout and Thermal Shutdown
Improved Replacement for LM2577-ADJ Series
Simple Boost and Flyback Converters
SEPIC Topology Permits Input Voltage to be Higher or Lower than Output Voltage