NCP1254数据手册集成电路（IC）的ACDC转换器离线开关规格书PDF

描述 Description

The NCP1254 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a TSOP-6 package. With a supply range up to 35 V, the controller hosts a jittered 65-kHz switching circuitry operated in peak current mode control. When the power on the secondary side starts to decrease, the controller automatically folds back its switching frequency down to a minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while freezing the peak current setpoint.To help building rugged converters, the controller features several key protective features: a non-dissipative Over Power Protection for a constant maximum output current regardless of the input voltage, two latched over voltage protection inputs - either through a dedicated pin or via the Vcc input and a dual-level auto-recover/latched overload/short-circuit timer. The controller architecture is designed to authorize a transient peak power excursion when the current setpoint hits the limit. At this point, the switching frequency is increased form 65 kHz to 130 kHz until the peak event disappears. The timer duration is then modulated as the converter crosses a peak power excursion mode (long) or undergoes a short circuit (short).

特性 Features

65kHz Fixed Frequency Current Mode control with 130 kHz frequency excursion
Allows peak power delivery without growing the transformer size by temporarily increasing the switching frequency
Internal and adjustable Over Power Protection (OPP) circuit
Compensates peak current for changing line conditions
Frequency Foldback down to 26 kHz and Skip-cycle in light load conditions
Optimized efficiency across the entire power range
Timer-based Auto-recovery Overload/Short-circuit protection with 100% to 25% timer reduction for short-circuit faults
Robust protection against both overload and short circuit conditions
Frequency Jittering in Normal and Frequency Foldback Modes
Softened EMI signature
Latch Input
Flexible input can be used for OVP or OTP protection
Double Vcc hiccup in fault mode
Reduced average power during fault mode

应用 Application

Ac-Dc adapters
Printer Power SuppliesNotebook Adapters

简介

NCP1254属于集成电路（IC）的ACDC转换器离线开关。由制造生产的NCP1254AC DC 转换器，离线开关该系列是元器件级控制产品，用于构建将交流市电转换为直流电（通常电压大幅降低）的设备。集成和未集成系统主要开关元件的器件均包括在内。由于高输入输出电压比，以及此类系统中通常需要隔离，这些器件通常与外部变压器配合使用。尽管通常使用定制变压器来实现此用途，但也有许多专门用于此用途的库存产品，请参见“开关转换器，SMPS 变压器”标题。