DESCRIPTION

The UC184xA family of control ICs provides all the necessary features to implement off-line fixed-frequency, current-mode switching power supplies with a minimum of external components. The current mode architecture demonstrates improved load regulation, pulse-by-pulse current limiting and inherent protection of the power supply output switch. The IC includes: A bandgap reference trimmed to ±1 accuracy, an error amplifier, a current sense comparator with internal clamp to 1V, a high current totem pole output stage for fast switching of power MOSFETs, and an externally programmable oscillator to set frequency and maximum duty cycle. The undervoltage lock-out is designed to operate with 250μA typ. start-up current, allowing an efficient bootstrap supply voltage design.

KEY FEATURES

■ LOW START-UP CURRENT. (0.5mA max.)

■ TRIMMED OSCILLATOR DISCHARGE CURRENT. (See Product Highlight)

■ OPTIMIZED FOR OFF-LINE AND DC-TO-DC CONVERTERS.

■ AUTOMATIC FEED FORWARD COMPENSATION.

■ PULSE-BY-PULSE CURRENT LIMITING.

■ ENHANCED LOAD RESPONSE CHARACTERISTICS.

■ UNDER-VOLTAGE LOCKOUT WITH HYSTERESIS.

■ DOUBLE PULSE SUPPRESSION.

■ HIGH-CURRENT TOTEM POLE OUTPUT.

■ INTERNALLY TRIMMED BANDGAP REFERENCE.

■ 500KHz OPERATION.

■ LOW RO ERROR AMPLIFIER.

APPLICATIONS

■ ECONOMICAL OFF-LINE FLYBACK OR FORWARD CONVERTERS.

■ DC-DC BUCK OR BOOST CONVERTERS.

■ LOW COST DC MOTOR CONTROL.

UC3845A屬于集成電路（IC） > DC-DC 開關(guān)控制器。美高森美公司制造生產(chǎn)的UC3845ADC-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?fù)浣Y(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。