NCP1240G中文资料控制器，固定频率，电流模式，双路 OCP，用于反激转换器数据手册ONSEMI规格书

描述 Description

The NCP1240 is a new fixed−frequency current−mode controller featuring Dynamic Self−Supply. This function greatly simplifies the design of the auxiliary supply and the VCC capacitor by activating the internal startup current source to supply the controller during start-up, transients, latch, stand-by etc. This device contains a special HV detector which detects the application unplug from the ac input line and triggers the X2 discharge current. This HV structure allows the brown-out detection as well. It features a timer-based fault detection that ensures the detection of overload and an adjustable compensation to help keep the maximum power independent of the input voltage. Due to frequency foldback, the controller exhibits excellent efficiency in light load condition while still achieving very low standby power consumption. Internal frequency jittering, ramp compensation, and a versatile latch input make this controller an excellent candidate for the robust power supply designs. A dedicated Off mode allows to reach the extremely low no load input power consumption via “sleeping” whole device and thus minimize the power consumption of the control circuitry. The NCP1240 differentiates itself from the rest of the fixed frequency flyback controllers with active X2 discharge and HV start up by implementing a Dual-Level Overcurrent protection. For some applications (e.g. limited power supplies), it is necessary that the controller maintains regulation while it has detected a first level of overload. This is to authorize a transient peak power higher than the maximum continuous output power.
This product is IEC60950 compliant. Please see the test report and certification in the Conformance report section below.

特性 Features

• Frequency foldback and skip mode
• Optimized efficiency across the entire load range
• Timer-based overload protection with latched (A version) or auto-recovery (B version) operation
• Protection against overcurrent and short circuit
• High-voltage startup with dynamic self supply
• Simplifies the design of the auxiliary supply
• Integrated brown-out detection
• Protects against any drops in line voltage
• Frequency Modulation
• Softened EMI signature
• Adjustable overpower protection
• Automatically adjusts the current limit depending on the line input voltage (high line or low line)
• Timer based Dual-Level Overcurrent protection
• This is to authorize a transient peak power higher than the maximum continuous output power.

应用 Application

• AC-DC Adapters
• Notebook Computers

简介

NCP1240G属于集成电路（IC）的ACDC转换器离线开关。由制造生产的NCP1240GAC 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。