描述 Description

The NCP1253 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 it's 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. To avoid sub harmonic oscillations in CCM operation, adjustable slope compensation is available via the series inclusion of a simple resistor in the current sense signal. Besides the auto-recovery timer-based short-circuit protection, an Over Voltage Protection on the Vcc pin protects the whole circuitry in case of optocoupler destruction or adverse open loop operation.

特性 Features

? Frequency Foldback down to 26 kHz and Skip-Cycle in Light Load
? Improved efficiency across the load range
? Internal Ramp Compensation
? Reduces the number of external components
? Frequency Jittering in Normal and Frequency Foldback modes
? Low EMI signature
? Over Voltage Protection (OVP) monitoring on the Vcc pin
? Protects against output over voltage conditions without any added components
? Timer-based Auto-Recovery or Latched Short-Circuit Protection
? Protection against fault conditions

應(yīng)用 Application

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

簡介

NCP1253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NCP1253AC DC 轉(zhuǎn)換器，離線開關(guān)該系列是元器件級控制產(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現(xiàn)此用途，但也有許多專門用于此用途的庫存產(chǎn)品，請參見“開關(guān)轉(zhuǎn)換器，SMPS 變壓器”標題。