描述 Description

The SG1844/45 family of control ICs provides all the required features to implement off-line Fixed Frequency, Current-mode switching power supplies with a minimum number of external components. Current-mode architecture demonstrates improved line regulation, improved load regulation, pulse-by pulse current limiting and inherent protection of the power supply output switch. The Bandgap reference is trimmed to ±1% over temperature. Oscillator discharge current is trimmed to less than ±10%. The SG1844/45 has under-voltage lockout, current-limiting circuitry and start-up current of less than 1mA. The totem-pole output is optimized to drive the gate of a power MOSFET. The output is low in the off state to provide direct interface to an Nchannel device. Both operate up to a maximum duty cycle range of zero to <50% due to an internal toggle flip-flop which blanks the output off every other clock cycle. The SG1844/45 is specified for operation over the full military ambient temperature range of -55°C to 125°C. The SG3844/45 is designed for the commercial range of 0°C to 70°C.Microchip Ordering Part? Standard Microcircuit Drawing (SMD)?SG1844F-DESC Cross Reference 5962-8670403HASG1844F-DESC Cross Reference 5962-8670403HXSG1844J-DESC Cross Reference 5962-8670403CASG1844J-DESC Cross Reference 5962-8670403CXSG1844L-DESC Cross Reference 5962-86704032ASG1844L-DESC Cross Reference 5962-86704032XSG1844Y-DESC Cross Reference 5962-8670403PASG1844Y-DESC Cross Reference 5962-8670403PX

特性 Features

Optimized For Off-Line Control
Low Start-Up Current (Automatic Feed Forward Compensation
Trimmed Oscillator Discharge Current
Pulse-By-Pulse Current Limiting
Enhanced Load Response Characteristics -Undervoltage Lockout with 6V Hysteresis
Double-Pulse Suppression
High-Current Totem-Pole Output (1A Peak)
Internally Trimmed Band-gap Reference
500kHz Operation Under-voltage Lockout: SG1844 - 16 volts
Low Shoot-Through Current <75mA Over Temperature

簡(jiǎn)介

SG1844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SG1844AC 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。