描述 Description

The NCP1250 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a tiny TSOP-6 package. With a supply range up to 28 V, the controller hosts a jittered 65 kHz or 100 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 limiting the peak current. 40W AdapterOver Power Protection (OPP) is a difficult exercise especially when no-load standby requirements drive the converter specifications. The ON proprietary integrated OPP lets you harness the maximum delivered power without affecting your standby performance simply via two external resistors. An Over Voltage Protection input is also combined on the same pin and protects the whole circuitry in case of optocoupler failure or adverse open loop operation. Finally, a timer-based short-circuit protection offers the best protection scheme, letting you precisely select the protection trip point irrespective of a loose coupling between the auxiliary and the power windings.

特性 Features

? Non-dissipative internal and adjustable Over Power Protection (OPP) circuits
? Limits maximum delivered power without affecting standby performance
? Frequency Foldback down to 26 kHz and Skip-Cycle in light load conditions
? High efficiency in light load conditions
? Internal Ramp Compensation
? Reduces the number of external components
? Frequency jittering from full load to skip-cycle
? Improved EMI performance
? Latch input for OVP and OTP implementations
? Simple implementation of required protection functions
? See NCP1251 for integrated Over Voltage Protection (OVP) monitoring on the Vcc pin

應(yīng)用 Application

? Offline Adapters
? AC-DC converters
? Set-top Boxes
? Printers
? Notebooks and Netbooks

簡介

NCP1250屬于集成電路（IC）的ACDC轉(zhuǎn)換器離線開關(guān)。由制造生產(chǎn)的NCP1250AC DC 轉(zhuǎn)換器，離線開關(guān)該系列是元器件級(jí)控制產(chǎn)品，用于構(gòu)建將交流市電轉(zhuǎn)換為直流電（通常電壓大幅降低）的設(shè)備。集成和未集成系統(tǒng)主要開關(guān)元件的器件均包括在內(nèi)。由于高輸入輸出電壓比，以及此類系統(tǒng)中通常需要隔離，這些器件通常與外部變壓器配合使用。盡管通常使用定制變壓器來實(shí)現(xiàn)此用途，但也有許多專門用于此用途的庫存產(chǎn)品，請(qǐng)參見“開關(guān)轉(zhuǎn)換器，SMPS 變壓器”標(biāo)題。