onsemi NCP1345 Quasi-Resonant Flyback Controllers

onsemi NCP1345 Quasi-Resonant Flyback Controllers are highly integrated devices designed for high-performance off-line USB-PD and USB Type-C™ power converters. The NCP1345 implements dual−pin VCC architecture for a direct connection to the aux winding. Simplified VCC management allows for a low part count and increased performance.

The onsemi NCP1345 Quasi-Resonant Flyback Controllers offer a precise, primary side-based output current limiting circuit enabling a constant output current limit regardless of programmed output voltage or nameplate output power.

The NCP1345 facilitates several key protective options, including internal brownout detection, a maximum output current limit regardless of input voltage, and a latched over-voltage and NTC−ready overtemperature protection via a dedicated pin. Additionally, line removal detection safely discharges the X2 capacitors when the line is removed, achieving converter ruggedness.

Features

Integrated high-voltage startup circuit with brownout detection
Integrated X2 capacitor discharge capability
Wide V_CCL range from 8V to 38V
150V V_CCH Pin for connection to high-voltage aux winding
36.5V V_CC Overvoltage protection
Primary side-based constant output current limiting
Abnormal overcurrent fault protection for winding short circuit detection
Internal temperature shutdown

Valley switching operation with valley-lockout for noise-free operation
Rapid frequency foldback for fast reduction of switching frequency
Skip mode with output voltage compensation
Minimized no load power consumption
Frequency jittering for reduced EMI signature
Latching or auto-recovery overload protection
Adjustable overpower protection
Fixed/adjustable maximum frequency clamp
Fault pin for severe fault conditions, NTC compatible for OTP

onsemi NCP1345 Quasi-Resonant Flyback Controllers

Features

Block Diagram

Typical Application Circuit

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