描述 Description

The SG1525A/1527A series of pulse width modulator integrated circuits are designed to offer improved performance and lower external parts count when used to implement all types of switching power supplies. The on-chip +5.1 volt reference is trimmed to ±1% initial accuracy and the input common-mode range of the error amplifier includes the reference voltage, eliminating external potentiometers and divider resistors. A Sync input to the oscillator allows multiple units to be slaved together, or a single unit to be synchronized to an external system clock. A single resistor between the CT pin and the Discharge pin provides a wide range of dead-time adjustment. These devices also feature built-in soft-start circuitry with only a timing capacitor required externally. A Shutdown pin controls both the soft-start circuitry and the output stages, providing instantaneous turn-off with soft-start recycle for slow turn-on. These functions are also controlled by an under-voltage lockout which keeps the outputs off and the soft-start capacitor discharged for input voltages less than that required for normal operation. Another unique feature of these PWM circuits is a latch following the comparator. Once a PWM pulse has been terminated for any reason, the outputs will remain off for the duration of the period. The latch is reset with each clock pulse. The output stages are totem-pole designs capable of sourcing or sinking in excess of 200mA. The SG1525A output stage features NOR logic, giving a LOW output for an OFF state. The SG1527A utilizes OR logic which results in a HIGH output level when OFF.

特性 Features

·8V to 35V operation
·5.1V reference trimmed to ±1%
·100Hz to 500KHz oscillator range
·Separate oscillator sync terminal
·Adjustable dead-time control
·Internal soft-start
·Input under-voltage lockout
·Latching P.W.M. to prevent multiple pulses
·Dual source/sink output drivers

簡介

SG1525AL屬于集成電路（IC）的PMIC-穩(wěn)壓器-DCDC開關式控制器。由制造生產(chǎn)的SG1525ALDC-DC 開關控制器PMIC（電源管理集成電路）DC 到 DC 開關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。其他拓撲結構可能包括：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。