描述 Description

The SG1842/43 family of control IC's provides all the necessary 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 band-gap reference is trimmed to ±1% over temperature. Oscillator discharge current is trimmed to less than ±10%. The SG1842/43 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 N-channel device. The SG1842/43 is specified for operation over the full military ambient temperature range of -55°C to 125°C. The SG2842/43 is specified for the industrial range of -25°C to 85°C, and the SG3842/43 is designed for the commercial range of 0°C to 70°C.Microchip Ordering Part? Standard Microcircuit Drawing (SMD)?SG1842Y-DESC Cross Reference 5962-8670401PASG1842Y-DESC Cross Reference 5962-8670401PX

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
Under-Voltage Lockout with 6V Hysteresis (SG1842only)
Double-Pulse Suppression
High-Current Totem-Pole Output (1A Peak)
Internally Trimmed Band-gap Reference
500kHz Operation Under-voltage Lockout: SG1842 - 16 volts, SG1843 - 8.4 volts
Low Shoot-Through Current <75mA Over Temperature

簡介

SG1842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SG1842AC 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。