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)?SG1845F-DESC Cross Reference 5962-8670404HASG1845F-DESC Cross Reference 5962-8670404HXSG1845J-DESC Cross Reference 5962-8670404CASG1845J-DESC Cross Reference 5962-8670404CXSG1845L-DESC Cross Reference 5962-86704042ASG1845L-DESC Cross Reference 5962-86704042XSG1845Y-DESC Cross Reference 5962-8670404PASG1845Y-DESC Cross Reference 5962-8670404PX

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 SG1845 - 8.4 Volts
Low Shoot-Through Current <75mA Over Temperature

簡介

SG1845屬于集成電路（IC）的PMIC-穩(wěn)壓器-DCDC開關(guān)式控制器。由制造生產(chǎn)的SG1845DC-DC 開關(guān)控制器PMIC（電源管理集成電路）DC 到 DC 開關(guān)式控制器是用于高效率電路的穩(wěn)壓 IC，其配置為生成高于（突升或步升）或低于（突降或步降）輸入電源的輸出電源電壓。其他拓撲結(jié)構(gòu)可能包括：降壓-升壓、反激、正激、Cuk、SEPIC、全橋、半橋和推挽式。這些器件不同于需要最小電壓并“燒盡”多余電壓的線性穩(wěn)壓器。